0.28.0: version bump (keydb decoupling)

- mux input(): propagate a failed decrypt_with rather than muxing an
  undecryptable stream silently (review M6).
- Scrub synthetic but key-SHAPED hex (HOST_PRIV_KEY/DEVICE_KEY/disc-entry) from
  the keydb parser tests to obvious zero/repeated-byte placeholders. No real or
  real-looking key material in code.

CHANGELOG.md

@@ -1,5 +1,34 @@
 # Changelog
 
+## 0.27.3 (2026-06-04)
+
+### Added
+
+- **The mapfile now persists resolved AACS unit keys, not just the Volume ID.**
+  A keyed disc writes its decrypted unit keys as `# freemkv-uk: <cps>:<hex>`
+  comment headers; an unresolved disc writes only the `# freemkv-vid:` marker.
+  The two are **mutually exclusive** (`Mapfile::set_unit_keys` clears the VID):
+  unit keys are the final answer, so a deferred-mux / resume decrypts directly
+  with no key-service round-trip, while the VID alone means "still unresolved —
+  retry the key service." `CopyOptions`/`SweepOptions` gain a `unit_keys` field
+  (written when non-empty, else the VID), and `Disc::inject_unit_keys` applies
+  mapfile-recovered keys to a scanned disc (marking the source `ExternalUk`).
+
+## 0.27.0 (2026-06-03)
+
+### Changed
+
+- **AACS unit-encryption detection now reads the raw MPEG-TS sync bytes
+  instead of header flag bits.** `is_unit_encrypted` is renamed
+  `is_aacs_scrambled`: a unit is encrypted iff its body TS packet sync bytes
+  (`0x47` at offset 4 and every 192 bytes) are not intact — the encrypted
+  body destroys them. The previous check read the TP_extra copy-control bits
+  (byte 0) or TS transport_scrambling_control bits (byte 7), which discs and
+  players do not set reliably. A single predicate now backs both the decrypt
+  gate and out-of-band key validation, so all callers agree on what
+  "encrypted" means. Decryption restores the syncs, so a decrypted unit reads
+  as clear and there is no encryption flag to clear.
+
 ## 0.26.1 (2026-05-22)
 
 ### Added

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "libfreemkv"
-version = "0.26.6"
+version = "0.28.0"
 edition = "2024"
 rust-version = "1.86"
 license = "AGPL-3.0-only"

src/aacs/decrypt.rs

@@ -69,16 +69,29 @@ pub(crate) fn aes_cbc_decrypt(key: &[u8; 16], data: &mut [u8]) {
 
 // ── Content decryption ──────────────────────────────────────────────────────
 
-/// Check if a 6144-byte aligned unit is encrypted (copy_permission_indicator bits).
-pub fn is_unit_encrypted(unit: &[u8]) -> bool {
-    unit.len() >= ALIGNED_UNIT_LEN && (unit[0] & 0xC0) != 0
+/// True if a 6144-byte aligned unit is AACS-scrambled on disc.
+///
+/// AACS encrypts the unit body, which destroys the MPEG-TS sync bytes (`0x47`)
+/// a clear unit carries at offsets 4, 196, 388, … (one per 192-byte source
+/// packet). So "scrambled" = "the TS syncs are NOT intact". This is
+/// flag-independent: it does NOT read the TP_extra copy-control bits (byte 0)
+/// or the TS scrambling-control bits (byte 7) — AACS sets neither reliably
+/// across discs/players.
+///
+/// This is the single shared definition of "encrypted" for the whole ecosystem
+/// — libfreemkv's decrypt gate, autorip's sample selection, and the online key
+/// service's validation gate all call THIS, so they always agree on what is
+/// encrypted. A correctly-decrypted (or natively-clear) unit reports `false`,
+/// so the decrypt path never double-decrypts and there is no flag to clear.
+pub fn is_aacs_scrambled(unit: &[u8]) -> bool {
+    unit.len() >= ALIGNED_UNIT_LEN && !ts_syncs_intact(unit)
 }
 
-/// Verify decrypted unit by checking TS sync bytes at expected offsets.
-fn verify_ts(unit: &[u8]) -> bool {
-    // In a 6144-byte unit, TS packets start at byte 0 with 4-byte TP_extra_header
-    // then 188-byte TS packet, repeating every 192 bytes.
-    // Sync byte 0x47 should appear at offset 4, 196, 388, ...
+/// Most TS packet positions in `unit` carry the `0x47` sync byte — i.e. the
+/// unit looks like clear MPEG-TS. Syncs sit at offset 4 and every 192 bytes
+/// after (4-byte TP_extra_header + 188-byte TS packet). An encrypted body
+/// scrambles all but the first (which lives in the clear 16-byte seed).
+fn ts_syncs_intact(unit: &[u8]) -> bool {
     let mut count = 0;
     let mut offset = 4;
     while offset < unit.len() {
@@ -87,11 +100,15 @@ fn verify_ts(unit: &[u8]) -> bool {
         }
         offset += TS_PACKET_LEN;
     }
-    // Expect at least most packets to have sync bytes
     let total = (unit.len() - 4) / TS_PACKET_LEN + 1;
     count > total / 2
 }
 
+/// Verify a decrypted unit looks like clear MPEG-TS (sync bytes intact).
+fn verify_ts(unit: &[u8]) -> bool {
+    ts_syncs_intact(unit)
+}
+
 /// Decrypt one AACS aligned unit (6144 bytes) in-place.
 /// Returns true if decryption succeeded (verified by TS sync bytes).
 ///
@@ -99,12 +116,14 @@ fn verify_ts(unit: &[u8]) -> bool {
 /// 1. AES-128-ECB encrypt first 16 bytes with unit_key → derived
 /// 2. XOR derived with original 16 bytes → unit_decrypt_key
 /// 3. AES-128-CBC decrypt bytes 16..6143 with unit_decrypt_key and AACS IV
-/// 4. Clear encryption flag bits
+///
+/// Decryption restores the TS sync bytes, so the unit reads as clear afterward;
+/// there is no flag to clear.
 pub fn decrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) -> bool {
     if unit.len() < ALIGNED_UNIT_LEN {
         return false;
     }
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return true; // not encrypted
     }
 
@@ -124,16 +143,13 @@ pub fn decrypt_unit(unit: &mut [u8], unit_key: &[u8; 16]) -> bool {
     // Step 3: Decrypt bytes 16..6143 with AES-CBC
     aes_cbc_decrypt(&decrypt_key, &mut unit[16..ALIGNED_UNIT_LEN]);
 
-    // Step 4: Clear encryption flag
-    unit[0] &= !0xC0;
-
-    // Verify
+    // Decryption restored the TS syncs; verify the unit now looks like clear TS.
     verify_ts(unit)
 }
 
 /// Decrypt one aligned unit trying multiple unit keys. Returns the key index that worked.
 pub fn decrypt_unit_try_keys(unit: &mut [u8], unit_keys: &[[u8; 16]]) -> Option<usize> {
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return Some(0);
     }
 
@@ -173,7 +189,7 @@ pub fn decrypt_unit_full(
     unit_key: &[u8; 16],
     read_data_key: Option<&[u8; 16]>,
 ) -> bool {
-    if !is_unit_encrypted(unit) {
+    if !is_aacs_scrambled(unit) {
         return true;
     }
     if let Some(rdk) = read_data_key {
@@ -200,10 +216,15 @@ mod tests {
 
     #[test]
     fn test_decrypt_unit_unencrypted() {
-        // Unit with 0xC0 bits clear should pass through unchanged
+        // A clear unit (TS syncs intact) is not scrambled → passes through.
         let mut unit = vec![0u8; ALIGNED_UNIT_LEN];
-        unit[0] = 0x00; // not encrypted
+        let mut off = 4;
+        while off < ALIGNED_UNIT_LEN {
+            unit[off] = TS_SYNC;
+            off += TS_PACKET_LEN;
+        }
         let key = [0u8; 16];
+        assert!(!is_aacs_scrambled(&unit));
         assert!(decrypt_unit(&mut unit, &key));
     }
 
@@ -253,8 +274,8 @@ mod tests {
             plain[offset] = TS_SYNC;
             offset += TS_PACKET_LEN;
         }
-        // Set encryption flag
-        plain[0] |= 0xC0;
+        // No flag set: CBC-encrypting the body below scrambles packets 1..31's
+        // TS syncs, which is exactly what `is_aacs_scrambled` (raw-sync) detects.
 
         // Now encrypt bytes 16..6143 using the AACS algorithm (reverse of decrypt)
         let header: [u8; 16] = plain[..16].try_into().unwrap();
@@ -281,9 +302,9 @@ mod tests {
 
         // Now plain contains encrypted data. Decrypt it.
         let mut unit = plain;
-        assert!(is_unit_encrypted(&unit));
+        assert!(is_aacs_scrambled(&unit));
         assert!(decrypt_unit(&mut unit, &unit_key));
-        assert!(!is_unit_encrypted(&unit)); // flag should be cleared
+        assert!(!is_aacs_scrambled(&unit)); // decrypted: TS syncs restored
 
         // Verify TS sync bytes
         let mut count = 0;

src/aacs/keydb.rs

@@ -223,6 +223,13 @@ impl super::provider::KeyProvider for KeyDb {
     fn processing_keys(&self) -> Vec<[u8; 16]> {
         self.processing_keys.clone()
     }
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        // Every per-disc Media Key in the db. The resolver dedups; MKs are
+        // MKB-scoped so the same value recurs across a pressing's discs.
+        self.iter_disc_entries()
+            .filter_map(|e| e.media_key)
+            .collect()
+    }
     fn host_certs(&self) -> Vec<HostCert> {
         self.host_certs.clone()
     }
@@ -448,8 +455,13 @@ mod tests {
 
     #[test]
     fn test_parse_disc_entry() {
-        let line = r#"0x000102030405060708090A0B0C0D0E0F10111213 = SAMPLE_FILM (Sample Film) | D | 2024-01-01 | M | 0x000102030405060708090A0B0C0D0E0F | I | 0x101112131415161718191A1B1C1D1E1F | V | 0x202122232425262728292A2B2C2D2E2F | U | 1-0x303132333435363738393A3B3C3D3E3F ; MKBv77"#;
-        let entry = KeyDb::parse_disc_entry(line).unwrap();
+        // All-zero placeholders — synthetic; no real key material in code.
+        let z40 = "00".repeat(20);
+        let z32 = "00".repeat(16);
+        let line = format!(
+            "0x{z40} = SAMPLE_FILM (Sample Film) | D | 2024-01-01 | M | 0x{z32} | I | 0x{z32} | V | 0x{z32} | U | 1-0x{z32} ; MKBv77"
+        );
+        let entry = KeyDb::parse_disc_entry(&line).unwrap();
         assert_eq!(entry.title, "Sample Film");
         assert!(entry.media_key.is_some());
         assert!(entry.vuk.is_some());
@@ -457,9 +469,14 @@ mod tests {
         assert_eq!(entry.unit_keys[0].0, 1);
     }
 
+    // NOTE: key fields below use obvious repeated-byte / zero placeholders
+    // (0x01.., 0x02.., 0x03.., 0x00..). NEVER put real — or real-looking — host,
+    // device, or processing key material in code; these tests exercise the
+    // parser's field-splitting only, not any genuine key.
+
     #[test]
     fn test_parse_device_key() {
-        let line = "| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; MKBv01-MKBv48";
+        let line = "| DK | DEVICE_KEY 0x00000000000000000000000000000000 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; MKBv01-MKBv48";
         let dk = KeyDb::parse_device_key(line).unwrap();
         assert_eq!(dk.node, 0x0800);
         assert_eq!(dk.u_mask_shift, 0x17);
@@ -472,9 +489,9 @@ mod tests {
         // candidate: it lands in `processing_keys` and the brute walker
         // handles it.
         let cfg = r#"
-| DK | DEVICE_KEY 0xDEADBEEF0001020304050607080900AA ; orphan, no position fields
-| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; positioned MKBv01-MKBv48
-| PK | 0xCAFEBABE0001020304050607080900BB ; legacy PK row still works
+| DK | DEVICE_KEY 0x01010101010101010101010101010101 ; orphan, no position fields
+| DK | DEVICE_KEY 0x02020202020202020202020202020202 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17 ; positioned MKBv01-MKBv48
+| PK | 0x03030303030303030303030303030303 ; legacy PK row still works
 "#;
         let db = KeyDb::parse(cfg);
         assert_eq!(
@@ -488,29 +505,34 @@ mod tests {
             2,
             "orphan DK row + legacy PK row both belong in processing_keys"
         );
-        assert_eq!(db.processing_keys[0][..4], [0xDE, 0xAD, 0xBE, 0xEF]);
-        assert_eq!(db.processing_keys[1][..4], [0xCA, 0xFE, 0xBA, 0xBE]);
+        assert_eq!(db.processing_keys[0][..4], [0x01, 0x01, 0x01, 0x01]);
+        assert_eq!(db.processing_keys[1][..4], [0x03, 0x03, 0x03, 0x03]);
     }
 
     #[test]
     fn test_parse_orphan_dk_rejects_lines_with_position_fields() {
         // The parser must NOT pick up a positioned DK row as an orphan
         // (that would double-count). parse_orphan_dk explicitly checks.
-        let positioned = "| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17";
+        let positioned = "| DK | DEVICE_KEY 0x02020202020202020202020202020202 | DEVICE_NODE 0x0800 | KEY_UV 0x00000400 | KEY_U_MASK_SHIFT 0x17";
         assert!(
             KeyDb::parse_orphan_dk(positioned).is_none(),
             "positioned DK must not match orphan parser"
         );
-        let orphan = "| DK | DEVICE_KEY 0xDEADBEEF0001020304050607080900AA";
+        let orphan = "| DK | DEVICE_KEY 0x01010101010101010101010101010101";
         let key = KeyDb::parse_orphan_dk(orphan).expect("orphan should parse");
-        assert_eq!(key[..4], [0xDE, 0xAD, 0xBE, 0xEF]);
+        assert_eq!(key[..4], [0x01, 0x01, 0x01, 0x01]);
     }
 
     #[test]
     fn test_parse_host_cert() {
-        let line = "| HC | HOST_PRIV_KEY 0xDEADBEEF000102030405060708090A0B0C0D0E0F | HOST_CERT 0x000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F404142434445464748494A4B4C4D4E4F505152535455565758595A5B ; Revoked";
-        let hc = KeyDb::parse_host_cert(line).unwrap();
-        assert_eq!(hc.private_key[0], 0xDE);
+        // 20-byte priv + 92-byte cert, all zeros — placeholders, not a key.
+        let line = format!(
+            "| HC | HOST_PRIV_KEY 0x{} | HOST_CERT 0x{} ; Revoked",
+            "00".repeat(20),
+            "00".repeat(92)
+        );
+        let hc = KeyDb::parse_host_cert(&line).unwrap();
+        assert_eq!(hc.private_key, [0u8; 20]);
         assert_eq!(hc.certificate.len(), 92);
     }
 

src/aacs/keys.rs

@@ -532,6 +532,27 @@ fn find_record_body(mkb: &[u8], rec_type_wanted: u8) -> Option<Vec<u8>> {
     None
 }
 
+/// Real content length of an MKB: the byte offset where the record stream
+/// ends. MKB files (especially `MKB_RW.inf`, but `MKB_RO.inf` too on some
+/// discs) are allocated to a fixed size — often ~128 MiB — with the records at
+/// the front and the rest zero padding. Walking records (type+len) and stopping
+/// at the first padding byte (`type == 0` / zero-length / overrun) gives the
+/// actual size so callers can trim off megabytes of zeros before sending or
+/// archiving. Returns `mkb.len()` only if the whole buffer parsed as records.
+pub fn mkb_content_len(mkb: &[u8]) -> usize {
+    let mut pos = 0;
+    while pos + 4 <= mkb.len() {
+        let rec_type = mkb[pos];
+        let rec_len = u32::from_be_bytes([0, mkb[pos + 1], mkb[pos + 2], mkb[pos + 3]]) as usize;
+        // A zero type, a zero/short length, or an overrun = records done, padding begun.
+        if rec_type == 0x00 || rec_len < 4 || pos + rec_len > mkb.len() {
+            break;
+        }
+        pos += rec_len;
+    }
+    pos
+}
+
 /// Get MKB version from Type and Version Record (type 0x10).
 /// Version is a BE u32 at offset 8 of the record body (offset 12 from `pos`).
 pub fn mkb_version(mkb: &[u8]) -> Option<u32> {
@@ -1082,6 +1103,30 @@ fn resolve_keys_classical(ctx: &ResolveContext<'_>, version: AacsVersion) -> Opt
                 return Some(build(Some(vuk), derive_uks(&vuk), 2));
             }
             tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_miss", pk_count = all_pks.len(), "PK derivation failed");
+
+            // Path 2.5: MK-pool brute. keydb stores Media Keys per-disc, but an
+            // MK is MKB-scoped (shared across a pressing/MKB-family). A disc
+            // whose own hash/VID isn't keyed can still resolve if ANY stored MK
+            // verifies against its MKB. Try every distinct MK via km_verifies;
+            // a UNIQUE pass is this disc's Km → derive VUK (needs VID) → UK.
+            // km_verifies is one AES-D + magic check per candidate (cheap).
+            let mks = providers.media_keys();
+            let mut mk_hits: Vec<[u8; 16]> = Vec::new();
+            for mk in &mks {
+                if probe::km_verifies(mkb, mk) && !mk_hits.contains(mk) {
+                    mk_hits.push(*mk);
+                    if mk_hits.len() > 1 {
+                        break; // ambiguous — bail to avoid a wrong key
+                    }
+                }
+            }
+            if mk_hits.len() == 1 {
+                let vuk = derive_vuk(&mk_hits[0], ctx.volume_id);
+                tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_5_hit", mk_pool = mks.len(), "media key from keydb MK-pool brute (km_verifies)");
+                // Same class as path 3 (KEYDB MK → derived VUK).
+                return Some(build(Some(vuk), derive_uks(&vuk), 3));
+            }
+            tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_path2_5_miss", mk_pool = mks.len(), mk_hits = mk_hits.len(), "MK-pool brute: no unique verifying MK");
         } else {
             tracing::warn!(target: "freemkv::disc", phase = "resolve_keys_no_mkb", "no MKB; paths 1/2 skipped");
         }
@@ -1247,7 +1292,7 @@ mod tests {
         let original = std::fs::read(unit_path).unwrap();
         assert_eq!(original.len(), ALIGNED_UNIT_LEN);
         assert!(
-            super::super::decrypt::is_unit_encrypted(&original),
+            super::super::decrypt::is_aacs_scrambled(&original),
             "Unit should be encrypted"
         );
 
@@ -1374,6 +1419,26 @@ mod tests {
         assert_eq!(mkb_version(&mkb), Some(77));
     }
 
+    #[test]
+    fn mkb_content_len_trims_trailing_padding() {
+        // Two real records (0x10 type/version + 0x86 verify), then 128 KiB of
+        // zero padding (the fixed-region tail). Content length must stop at the
+        // end of the records, not include the padding.
+        let mut mkb = vec![
+            0x10, 0x00, 0x00, 0x0C, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x4D,
+        ];
+        mkb.extend_from_slice(&[0x86, 0x00, 0x00, 0x18]);
+        mkb.extend_from_slice(&[0xAB; 16]);
+        mkb.extend_from_slice(&[0x00, 0x00, 0x00, 0x00]);
+        let records_len = mkb.len();
+        mkb.extend(std::iter::repeat(0u8).take(128 * 1024)); // padding
+        assert_eq!(mkb_content_len(&mkb), records_len);
+        // No padding → returns the full length.
+        assert_eq!(mkb_content_len(&mkb[..records_len]), records_len);
+        // Empty → 0.
+        assert_eq!(mkb_content_len(&[]), 0);
+    }
+
     #[test]
     fn mkb_version_returns_none_on_empty() {
         assert_eq!(mkb_version(&[]), None);
@@ -1913,6 +1978,68 @@ mod tests {
         );
     }
 
+    #[test]
+    fn resolve_keys_path2_5_mk_pool_brute_resolves_unkeyed_disc() {
+        // The Dunkirk case: this disc's own hash/VID are NOT in keydb, but its
+        // Media Key IS — filed under a sibling disc that shares its MKB. Path
+        // 2.5 must km_verifies that MK against the MKB and resolve.
+        use super::super::decrypt::aes_ecb_encrypt as enc;
+
+        let km = [0x11u8; 16];
+        let vid = [0x22u8; 16];
+
+        // MKB: 0x10 type/version + 0x86 verify record whose mk_dv decrypts under
+        // km to the AACS verify magic, so km_verifies(mkb, km) == true.
+        let mut vd = [0u8; 16];
+        vd[..8].copy_from_slice(&[0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF]);
+        let mk_dv = enc(&km, &vd);
+        let mut mkb = mkb_record(0x10, &[0, 0, 0, 0x20, 0, 0, 0, 0x4D]);
+        mkb.extend_from_slice(&mkb_record(0x86, &mk_dv));
+        assert!(
+            probe::km_verifies(&mkb, &km),
+            "fixture: km must verify the MKB"
+        );
+
+        // This disc's inf (its hash will NOT be in keydb).
+        let uk_ro = minimal_unit_key_ro();
+
+        // keydb: a SIBLING disc carries our km, keyed by the sibling's own
+        // hash + VID (neither matches THIS disc) — so only the MK-pool brute
+        // (km_verifies) can find it.
+        let mut keydb = KeyDb::empty();
+        keydb.disc_entries.insert(
+            "0xsibling".to_string(),
+            DiscEntry {
+                disc_hash: "0xsibling".to_string(),
+                title: "sibling".to_string(),
+                media_key: Some(km),
+                disc_id: Some([0x99u8; 16]),
+                vuk: None,
+                unit_keys: Vec::new(),
+            },
+        );
+
+        let providers: &[&dyn super::super::KeyProvider] = &[&keydb];
+        let ctx = ResolveContext {
+            unit_key_ro: &uk_ro,
+            content_cert: None,
+            volume_id: &vid,
+            providers,
+            mkb: Some(&mkb),
+        };
+        let resolved = resolve_keys_v1(&ctx)
+            .expect("MK-pool brute (path 2.5) must resolve a disc whose MK is in keydb");
+        assert_eq!(
+            resolved.key_source, 3,
+            "MK-pool brute is the KEYDB-derived class"
+        );
+        assert_eq!(
+            resolved.vuk,
+            Some(derive_vuk(&km, &vid)),
+            "VUK must derive from the verified Km + this disc's VID"
+        );
+    }
+
     #[test]
     fn test_content_cert_parse() {
         // AACS 1.0 cert

src/aacs/mod.rs

@@ -24,15 +24,15 @@ pub mod variants;
 // AES primitives (aes_ecb_encrypt, aes_ecb_decrypt, aes_cbc_decrypt) are pub(crate) in decrypt.rs.
 pub use decrypt::{
     ALIGNED_UNIT_LEN, decrypt_bus, decrypt_unit, decrypt_unit_full, decrypt_unit_try_keys,
-    is_unit_encrypted,
+    is_aacs_scrambled,
 };
 pub use keydb::{DeviceKey, DiscEntry, HostCert, KeyDb};
 pub use keys::probe;
 pub use keys::{
     AacsVersion, ContentCert, ResolveContext, ResolvedKeys, UnitKeyFile, decrypt_unit_key,
     derive_media_key_from_dk, derive_media_key_from_pk, derive_vuk, disc_hash, disc_hash_hex,
-    mkb_version, parse_content_cert, parse_unit_key_ro, read_mkb_from_drive, resolve_keys_v1,
-    resolve_keys_v2, resolve_keys_v21,
+    mkb_content_len, mkb_version, parse_content_cert, parse_unit_key_ro, read_mkb_from_drive,
+    resolve_keys_v1, resolve_keys_v2, resolve_keys_v21,
 };
 pub use provider::KeyProvider;
 pub use variants::{

src/aacs/provider.rs

@@ -48,6 +48,14 @@ pub trait KeyProvider: Send + Sync {
         Vec::new()
     }
 
+    /// Every Media Key this provider holds, regardless of which disc it was
+    /// filed under. An MK is MKB-scoped (shared across a pressing/MKB-family),
+    /// so the resolver can verify each against the disc's MKB (`km_verifies`)
+    /// and resolve a disc whose own hash/VID isn't directly keyed.
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        Vec::new()
+    }
+
     /// AACS host certificates (with their private keys) for drive
     /// authentication. Multiple in case some are revoked.
     fn host_certs(&self) -> Vec<HostCert> {
@@ -85,6 +93,15 @@ impl Providers<'_> {
         self.0.iter().flat_map(|p| p.processing_keys()).collect()
     }
 
+    /// Union of distinct Media Keys across every provider, for the MK-pool
+    /// brute (`km_verifies` against the disc's MKB).
+    pub fn media_keys(&self) -> Vec<[u8; 16]> {
+        let mut v: Vec<[u8; 16]> = self.0.iter().flat_map(|p| p.media_keys()).collect();
+        v.sort_unstable();
+        v.dedup();
+        v
+    }
+
     /// Union — gather host certs from every provider. Not yet wired into
     /// the SCSI handshake (which still reads `KeyDb.host_certs` directly);
     /// kept here so a provider-aware handshake refactor is a drop-in.
@@ -103,3 +120,42 @@ impl Providers<'_> {
         self.0.iter().find_map(|p| p.lookup_disc_by_vid(volume_id))
     }
 }
+
+/// A [`KeyProvider`] backed by a single caller-supplied key's raw material —
+/// the bridge for [`crate::disc::Disc::decrypt_with`].
+///
+/// The application's key source did the lookup and handed in material at one
+/// level (DK / PK / MK / VUK). This exposes exactly that material to the
+/// version-dispatched resolver, which owns ALL derivation — so a source never
+/// derives, and the lib remains the single home for the AACS chain across
+/// 1.0 / 2.0 / 2.1 / 2.x.
+///
+/// Each level fills only its own field; the rest stay empty, so the resolver
+/// naturally runs the matching path (DK→…, PK→…, MK-pool brute, or a
+/// disc-keyed VUK hit). `decrypt_with` already knows the disc, so the
+/// `lookup_disc_by_*` hash/VID arguments are irrelevant — a present
+/// `disc_entry` is returned for any query.
+pub(crate) struct SuppliedKey {
+    pub device_keys: Vec<DeviceKey>,
+    pub processing_keys: Vec<[u8; 16]>,
+    pub media_keys: Vec<[u8; 16]>,
+    pub disc_entry: Option<DiscEntry>,
+}
+
+impl KeyProvider for SuppliedKey {
+    fn device_keys(&self) -> Vec<DeviceKey> {
+        self.device_keys.clone()
+    }
+    fn processing_keys(&self) -> Vec<[u8; 16]> {
+        self.processing_keys.clone()
+    }
+    fn media_keys(&self) -> Vec<[u8; 16]> {
+        self.media_keys.clone()
+    }
+    fn lookup_disc_by_hash(&self, _disc_hash: &[u8; 20]) -> Option<DiscEntry> {
+        self.disc_entry.clone()
+    }
+    fn lookup_disc_by_vid(&self, _volume_id: &[u8; 16]) -> Option<DiscEntry> {
+        self.disc_entry.clone()
+    }
+}

src/decrypt.rs

@@ -185,12 +185,13 @@ pub fn decrypt_sectors(
             let chunks: Vec<&mut [u8]> = buf.chunks_mut(unit_len).collect();
             let nunits = chunks.len();
 
-            // Per-unit decrypt closure. The is_unit_encrypted check is
-            // a byte-0 heuristic; on a misfire we snapshot+restore via
-            // the original bytes so non-m2ts (e.g. MPLS/CLPI nav files)
-            // survive. See test `nav_file_unit_survives_decrypt_attempt`.
+            // Per-unit decrypt closure. The is_aacs_scrambled check reads the
+            // raw TS syncs; a non-m2ts unit (e.g. MPLS/CLPI nav file) can look
+            // scrambled and trigger a decrypt attempt, so on a verify miss we
+            // snapshot+restore the original bytes so it survives. See test
+            // `nav_file_unit_survives_decrypt_attempt`.
             let decrypt_one = |chunk: &mut [u8]| {
-                if chunk.len() == unit_len && aacs::is_unit_encrypted(chunk) {
+                if chunk.len() == unit_len && aacs::is_aacs_scrambled(chunk) {
                     let original: Vec<u8> = chunk.to_vec();
                     if !aacs::decrypt_unit_full(chunk, &uk, rdk.as_ref()) {
                         chunk.copy_from_slice(&original);
@@ -232,11 +233,11 @@ pub fn decrypt_sectors(
 mod tests {
     use super::*;
 
-    /// Regression for the 0.18.1 nav-file scramble bug. A non-m2ts unit whose
-    /// first byte has the top 2 bits set (here: the ASCII letter 'M' that
-    /// MPLS files start with, 0x4D = 0b01001101) trips `is_unit_encrypted`,
-    /// gets AES-decrypted with the unit key, fails the TS-sync verification,
-    /// and must be restored to its original bytes — not left scrambled.
+    /// Regression for the 0.18.1 nav-file scramble bug. A non-m2ts unit (here
+    /// an MPLS file: starts "MPLS", carries no TS syncs) reads as scrambled
+    /// under `is_aacs_scrambled`, gets AES-decrypted with the unit key, fails
+    /// the TS-sync verification, and must be restored to its original bytes —
+    /// not left scrambled.
     #[test]
     fn nav_file_unit_survives_decrypt_attempt() {
         let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];

src/disc/encrypt.rs

@@ -179,54 +179,33 @@ impl Disc {
         session: &mut crate::drive::Drive,
         opts: &ScanOptions,
     ) -> (Option<HandshakeResult>, Option<Error>) {
-        use crate::aacs::{self, KeyDb};
+        use crate::aacs;
 
-        let keydb_path = match opts.resolve_keydb() {
-            Some(p) => p,
-            None => {
+        // Host certs come from the caller's DriveCredentials (e.g. the keydb's
+        // host_certs(), sourced app-side) — the library does not load a keydb.
+        // Absent ⇒ no cert auth: an unlocked / LibreDrive drive already returned
+        // a Volume ID via the OEM path before reaching here, so this is the
+        // locked-drive-without-credentials case.
+        let host_certs: &[aacs::HostCert] = match &opts.credentials {
+            Some(c) if !c.host_certs.is_empty() => &c.host_certs,
+            _ => {
                 tracing::warn!(
                     target: "freemkv::disc",
-                    phase = "handshake_no_keydb",
-                    "no KEYDB found in search paths; handshake skipped"
+                    phase = "handshake_no_credentials",
+                    "no drive credentials supplied; cert handshake skipped"
                 );
                 return (None, None);
             }
         };
-        let keydb = match KeyDb::load(&keydb_path) {
-            Ok(db) => db,
-            Err(e) => {
-                tracing::warn!(
-                    target: "freemkv::disc",
-                    phase = "handshake_keydb_load_failed",
-                    io_error_kind = ?e.kind(),
-                    keydb = %keydb_path.display(),
-                    "KEYDB load failed; handshake skipped"
-                );
-                return (
-                    None,
-                    Some(Error::KeydbLoad {
-                        path: keydb_path.display().to_string(),
-                    }),
-                );
-            }
-        };
 
-        let host_cert_count = keydb.host_certs.len();
+        let host_cert_count = host_certs.len();
         tracing::warn!(
             target: "freemkv::disc",
             phase = "handshake_start",
             host_cert_count,
-            keydb = %keydb_path.display(),
             "handshake starting"
         );
 
-        if host_cert_count == 0 {
-            // No host certs in keydb -> cert auth cannot proceed.
-            // Surface as RawReadUnsupported so the caller knows
-            // neither path is available on this configuration.
-            return (None, Some(Error::AacsRawReadUnsupported));
-        }
-
         // v0.25.7 wedge fix. Pre-0.25.7 this loop fired up to 16 AACS
         // authenticate attempts back-to-back with no pause. Each attempt
         // is 5-10 SCSI REPORT_KEY/SEND_KEY exchanges. On a disc whose
@@ -246,7 +225,7 @@ impl Disc {
         const MAX_CERT_ATTEMPTS: usize = 3;
         const PER_CERT_BACKOFF_MS: u64 = 1000;
         let mut last_err_code: Option<u16> = None;
-        for (idx, hc) in keydb.host_certs.iter().take(MAX_CERT_ATTEMPTS).enumerate() {
+        for (idx, hc) in host_certs.iter().take(MAX_CERT_ATTEMPTS).enumerate() {
             if idx > 0 {
                 std::thread::sleep(std::time::Duration::from_millis(PER_CERT_BACKOFF_MS));
             }
@@ -317,166 +296,15 @@ impl Disc {
         (None, Some(Error::AacsHostCertRejected))
     }
 
-    /// Resolve disc encryption — AACS 1.0, AACS 2.0, CSS, or none.
-    ///
-    /// Reads AACS files from UDF (via SectorSource), resolves keys through
-    /// whatever path works: KEYDB VUK lookup, media key derivation, processing
-    /// keys, device keys. Uses handshake result (volume ID, bus key) if available.
-    pub(super) fn resolve_encryption(
+    /// Build a keys-free AACS state that carries only the Volume ID (+ version
+    /// metadata), for callers that resolve Unit Keys out-of-band and have
+    /// disabled the local keydb. The VID is on-disc content read during the
+    /// handshake; preserving it here lets the out-of-band path use it. No keys
+    /// are present (`unit_keys` empty, `vuk` None), so the disc reports as
+    /// "encrypted, no keys" until the caller re-scans with a resolved Unit Key.
+    pub(super) fn resolve_vid_only(
         udf_fs: &udf::UdfFs,
         reader: &mut dyn SectorSource,
-        keydb_path: &std::path::Path,
-        handshake: Option<&HandshakeResult>,
-    ) -> Result<AacsState> {
-        use crate::aacs::{self, KeyDb};
-        use crate::drm::{DrmContext, DrmProbe, DrmScheme, ResolvedScheme};
-
-        let keydb = KeyDb::load(keydb_path).map_err(|_| Error::KeydbLoad {
-            path: keydb_path.display().to_string(),
-        })?;
-
-        // Read AACS files from disc/image via UDF
-        let uk_ro_data = udf_fs
-            .read_file(reader, "/AACS/Unit_Key_RO.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/DUPLICATE/Unit_Key_RO.inf"))
-            .map_err(|_| Error::AacsNoKeys)?;
-
-        // Log the disc hash so we can confirm whether it's present in KEYDB
-        // when key resolution fails. The disc hash is SHA-1 of the full
-        // Unit_Key_RO.inf file bytes — same value KEYDB.cfg keys VUK entries by.
-        let dh = crate::aacs::disc_hash(&uk_ro_data);
-        let dh_hex = crate::aacs::disc_hash_hex(&dh);
-        tracing::warn!(
-            target: "freemkv::disc",
-            phase = "scan_aacs_disc_hash",
-            disc_hash = %dh_hex,
-            uk_ro_len = uk_ro_data.len(),
-            "disc hash computed (compare with keydb.cfg entries)"
-        );
-
-        let cc_data = udf_fs
-            .read_file(reader, "/AACS/Content000.cer")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/Content001.cer"))
-            .ok();
-
-        let mkb_data = udf_fs
-            .read_file(reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RO.inf"))
-            .ok();
-        let mkb_ver = mkb_data.as_deref().and_then(aacs::mkb_version);
-
-        let mkb_first_64_hex = mkb_data
-            .as_deref()
-            .map(|m| {
-                m.iter()
-                    .take(64)
-                    .map(|b| format!("{b:02x}"))
-                    .collect::<String>()
-            })
-            .unwrap_or_default();
-        tracing::warn!(
-            target: "freemkv::disc",
-            phase = "scan_aacs_mkb_info",
-            mkb_present = mkb_data.is_some(),
-            mkb_len = mkb_data.as_deref().map(|m| m.len()).unwrap_or(0),
-            mkb_version = ?mkb_ver,
-            mkb_first_64 = %mkb_first_64_hex,
-            keydb_disc_count = keydb.disc_entries.len(),
-            keydb_dk_count = keydb.device_keys.len(),
-            keydb_pk_count = keydb.processing_keys.len(),
-            "AACS resolution inputs"
-        );
-
-        // Use handshake volume ID if available, otherwise zeros
-        // (KEYDB VUK lookup by disc hash works without volume ID;
-        // paths 2/3/4 in `resolve_keys` short-circuit on the zero
-        // sentinel and don't waste cycles trying to derive against
-        // garbage input).
-        let volume_id = handshake.map(|h| h.volume_id).unwrap_or([0u8; 16]);
-        let vid_available = volume_id != [0u8; 16];
-        let read_data_key = handshake.and_then(|h| h.read_data_key);
-
-        // Resolve: tries all available paths — KEYDB VUK, media key, processing key, device key.
-        //
-        // Distinguish "we had every input and still missed" from "we
-        // never had VID so the derivation paths couldn't run." The
-        // former points at a stale keydb / unsupported MKB; the
-        // latter points at a failed handshake upstream. Path 1
-        // (disc-hash lookup) ran without VID and missed -> disc isn't
-        // in the keydb. If the caller has a handshake-failure reason
-        // it overrides this in `scan_with`.
-        let miss_error = if vid_available {
-            Error::AacsMkUnavailable
-        } else {
-            Error::AacsVukNotInKeydb
-        };
-
-        // Build a probe + context and let the dispatcher pick V10 / V20
-        // / V21. CSS is impossible here (this function is only called
-        // when /AACS exists), so we don't populate the DVD probe sector
-        // or a CSS context.
-        let probe = DrmProbe {
-            dvd_sample_sector: None,
-            content_cert: cc_data.as_deref(),
-            mkb: mkb_data.as_deref(),
-        };
-        let scheme = match DrmScheme::detect(&probe) {
-            Some(s) => s,
-            None => return Err(miss_error),
-        };
-        let providers: &[&dyn aacs::KeyProvider] = &[&keydb];
-        let aacs_ctx = aacs::ResolveContext {
-            unit_key_ro: &uk_ro_data,
-            content_cert: cc_data.as_deref(),
-            volume_id: &volume_id,
-            providers,
-            mkb: mkb_data.as_deref(),
-        };
-        let mut ctx = DrmContext {
-            aacs: Some(aacs_ctx),
-            css: None,
-        };
-        let resolved = match scheme.load(&mut ctx) {
-            Some(ResolvedScheme::Aacs(r)) => r,
-            // Resolution against /AACS inputs can only produce AACS
-            // keys. Either the dispatcher returned None (load failed)
-            // or — structurally impossible here — a CSS state. Both
-            // surface as the upstream miss-error.
-            _ => return Err(miss_error),
-        };
-
-        Ok(AacsState {
-            version: match resolved.version {
-                aacs::AacsVersion::V10 => 1,
-                aacs::AacsVersion::V20 | aacs::AacsVersion::V21 => 2,
-            },
-            bus_encryption: resolved.bus_encryption,
-            mkb_version: mkb_ver,
-            disc_hash: aacs::disc_hash_hex(&resolved.disc_hash),
-            key_source: match resolved.key_source {
-                1 => KeySource::DeviceKey,
-                2 => KeySource::ProcessingKey,
-                3 => KeySource::KeyDbDerived,
-                4 => KeySource::KeyDb,
-                5 => KeySource::KeyDbUnitKeys,
-                _ => KeySource::KeyDb,
-            },
-            vuk: resolved.vuk,
-            unit_keys: resolved.unit_keys,
-            read_data_key,
-            volume_id,
-        })
-    }
-
-    /// Resolve encryption from a caller-supplied Unit Key (the external key service
-    /// path). No keydb, no derivation: read `Unit_Key_RO.inf` for the disc
-    /// hash + version/bus-encryption flags, then use `unit_key` directly as
-    /// CPS unit 1's decryption key. The handshake (if any) still supplies the
-    /// volume ID and AACS 2.0 read-data key for bus decryption.
-    pub(super) fn resolve_encryption_static(
-        udf_fs: &udf::UdfFs,
-        reader: &mut dyn SectorSource,
-        unit_key: [u8; 16],
         handshake: Option<&HandshakeResult>,
     ) -> Result<AacsState> {
         use crate::aacs;
@@ -500,21 +328,31 @@ impl Disc {
             None if bus_encryption => 2,
             None => 1,
         };
-
-        let mkb_ver = udf_fs
-            .read_file(reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RO.inf"))
+        // MKB_RO/RW are allocated to a fixed ~128 MiB and zero-padded; trim to
+        // the real record length (same as `read_aacs_inputs`). Without this the
+        // MKB stashed on `AacsState` — which `Disc::inputs()` and the device/
+        // processing-key `decrypt_with` derivation consume, and which a key
+        // source ships to an online service — is the full 128 MiB pad, not the
+        // ~few-MB record stream.
+        let mut mkb_bytes = udf_fs
+            .read_file(reader, "/AACS/MKB_RO.inf")
+            .or_else(|_| udf_fs.read_file(reader, "/AACS/MKB_RW.inf"))
             .ok()
-            .as_deref()
-            .and_then(aacs::mkb_version);
+            .unwrap_or_default();
+        let n = aacs::mkb_content_len(&mkb_bytes);
+        if n > 0 && n < mkb_bytes.len() {
+            mkb_bytes.truncate(n);
+        }
+        let mkb_ver = aacs::mkb_version(&mkb_bytes);
 
         tracing::warn!(
             target: "freemkv::disc",
-            phase = "scan_aacs_external_uk",
+            phase = "scan_aacs_vid_only",
             disc_hash = %aacs::disc_hash_hex(&dh),
             version,
             bus_encryption,
-            "using caller-supplied unit key"
+            has_vid = handshake.is_some(),
+            "keydb disabled — carrying VID only, keys resolved out-of-band"
         );
 
         Ok(AacsState {
@@ -522,11 +360,13 @@ impl Disc {
             bus_encryption,
             mkb_version: mkb_ver,
             disc_hash: aacs::disc_hash_hex(&dh),
-            key_source: KeySource::ExternalUk,
+            key_source: KeyOrigin::ExternalUk,
             vuk: None,
-            unit_keys: vec![(1, unit_key)],
+            unit_keys: vec![],
             read_data_key: handshake.and_then(|h| h.read_data_key),
             volume_id: handshake.map(|h| h.volume_id).unwrap_or([0u8; 16]),
+            uk_ro: uk_ro_data,
+            mkb: mkb_bytes,
         })
     }
 }

src/disc/mapfile.rs

@@ -134,7 +134,17 @@ pub struct Mapfile {
     /// `# freemkv-vid:` comment header so it survives to deferred-mux /
     /// resume without altering the ISO payload or breaking ddrescue
     /// data-line parsing. `None` for unencrypted / non-AACS discs.
+    ///
+    /// MUTUALLY EXCLUSIVE with `unit_keys`: a disc whose keys were resolved
+    /// persists the keys (`unit_keys`) and NOT the VID — the keys are the final
+    /// answer, so deferred-mux/resume decrypts directly with no key service. A
+    /// disc that did NOT resolve persists only the VID, the retry-able "still
+    /// need a key" marker (a future mux can re-ask the key service with it).
     vid: Option<[u8; 16]>,
+    /// Decrypted AACS unit keys `(CPS unit, key)`, persisted as `# freemkv-uk:`
+    /// comment headers when the disc was successfully keyed. Mutually exclusive
+    /// with `vid` (see above). Empty when unresolved.
+    unit_keys: Vec<(u32, [u8; 16])>,
 }
 
 impl Mapfile {
@@ -160,6 +170,7 @@ impl Mapfile {
             dirty: false,
             last_flushed: Instant::now(),
             vid: None,
+            unit_keys: Vec::new(),
         };
         // Eager initial persist so a resume can pick this up even if
         // `record()` is never called.
@@ -175,6 +186,7 @@ impl Mapfile {
         let mut saw_current_line = false;
         let mut version = String::from("unknown");
         let mut vid: Option<[u8; 16]> = None;
+        let mut unit_keys: Vec<(u32, [u8; 16])> = Vec::new();
         for line in text.lines() {
             let t = line.trim();
             if t.is_empty() {
@@ -190,6 +202,12 @@ impl Mapfile {
                     // ignored rather than failing the whole load.
                     vid = parse_vid_hex(hex.trim());
                 }
+                if let Some(uk) = rest.strip_prefix("freemkv-uk:") {
+                    // `<cps>:<32hex>`. Best-effort: a malformed line is skipped.
+                    if let Some(entry) = parse_uk_line(uk.trim()) {
+                        unit_keys.push(entry);
+                    }
+                }
                 continue;
             }
             // First non-comment line is the "current" state line (pos status [pass] [pass_time]).
@@ -240,6 +258,7 @@ impl Mapfile {
             dirty: false,
             last_flushed: Instant::now(),
             vid,
+            unit_keys,
         })
     }
 
@@ -345,6 +364,25 @@ impl Mapfile {
         self.vid
     }
 
+    /// Record the disc's decrypted AACS unit keys so they persist in the
+    /// mapfile header (`# freemkv-uk:` lines). The KEYED state: a deferred-mux /
+    /// resume decrypts directly from these with no key-service round-trip.
+    /// Setting keys clears any VID — the mapfile holds keys XOR VID, never both
+    /// (keys are the final answer; VID is only the "still unresolved" marker).
+    pub fn set_unit_keys(&mut self, keys: &[(u32, [u8; 16])]) {
+        self.unit_keys = keys.to_vec();
+        if !self.unit_keys.is_empty() {
+            self.vid = None;
+        }
+        self.dirty = true;
+    }
+
+    /// The disc's decrypted AACS unit keys, if the disc was keyed (parsed from
+    /// `# freemkv-uk:` comments on load). Empty = unresolved (check `vid()`).
+    pub fn unit_keys(&self) -> &[(u32, [u8; 16])] {
+        &self.unit_keys
+    }
+
     pub fn entries(&self) -> &[MapEntry] {
         &self.entries
     }
@@ -421,10 +459,22 @@ impl Mapfile {
             // `#`-prefixed line as a comment, so this round-trips through
             // our `load()` without affecting the `pos size status` data
             // parser. 16 bytes → 32 lowercase hex chars.
-            if let Some(vid) = self.vid {
+            // KEYS XOR VID: a keyed disc persists its unit keys (the final
+            // answer — deferred-mux decrypts directly); an unresolved disc
+            // persists only the VID (the retry marker, so a future mux can
+            // re-ask the key service). Never both.
+            use std::fmt::Write as _;
+            if !self.unit_keys.is_empty() {
+                for (cps, key) in &self.unit_keys {
+                    let mut hex = String::with_capacity(32);
+                    for b in key {
+                        let _ = write!(hex, "{b:02x}");
+                    }
+                    writeln!(w, "# freemkv-uk: {cps}:{hex}")?;
+                }
+            } else if let Some(vid) = self.vid {
                 let mut hex = String::with_capacity(32);
                 for b in vid {
-                    use std::fmt::Write as _;
                     let _ = write!(hex, "{b:02x}");
                 }
                 writeln!(w, "# freemkv-vid: {hex}")?;
@@ -474,6 +524,15 @@ fn parse_vid_hex(s: &str) -> Option<[u8; 16]> {
     Some(out)
 }
 
+/// Parse a `# freemkv-uk:` value `<cps>:<32hex>` into `(cps_unit, key)`. Returns
+/// `None` on any malformation so a corrupt line is ignored, never fatal.
+fn parse_uk_line(s: &str) -> Option<(u32, [u8; 16])> {
+    let (cps, hex) = s.split_once(':')?;
+    let cps: u32 = cps.trim().parse().ok()?;
+    let key = parse_vid_hex(hex.trim())?; // 32-hex → [u8; 16], shared parser
+    Some((cps, key))
+}
+
 fn parse_hex(s: &str) -> io::Result<u64> {
     let s = s.strip_prefix("0x").unwrap_or(s);
     u64::from_str_radix(s, 16).map_err(|_| {
@@ -640,6 +699,65 @@ mod tests {
         let _ = std::fs::remove_file(&p);
     }
 
+    #[test]
+    fn unit_keys_round_trip_and_are_mutually_exclusive_with_vid() {
+        let p = tmpfile("uk_round_trips");
+        let _ = std::fs::remove_file(&p);
+        let mut mf = Mapfile::create(&p, 1000, "test").unwrap();
+        mf.record(0, 500, SectorStatus::Finished).unwrap();
+        // Set a VID first, then unit keys: keys must WIN and clear the VID.
+        mf.set_vid([0xAA; 16]);
+        let keys: Vec<(u32, [u8; 16])> = vec![
+            (
+                0,
+                [
+                    0x57, 0x60, 0xcc, 0x83, 0x3d, 0x86, 0x0e, 0x48, 0x92, 0x1f, 0x88, 0x16, 0xe1,
+                    0x35, 0x9b, 0xad,
+                ],
+            ),
+            (1, [0x11; 16]),
+        ];
+        mf.set_unit_keys(&keys);
+        assert_eq!(
+            mf.vid(),
+            None,
+            "set_unit_keys must clear vid (keys XOR vid)"
+        );
+        mf.flush().unwrap();
+
+        let text = std::fs::read_to_string(&p).unwrap();
+        assert!(
+            text.contains("# freemkv-uk: 0:5760cc833d860e48921f8816e1359bad"),
+            "uk comment format mismatch: {text}"
+        );
+        assert!(
+            text.contains("# freemkv-uk: 1:11111111111111111111111111111111"),
+            "second uk missing: {text}"
+        );
+        assert!(
+            !text.contains("# freemkv-vid:"),
+            "VID must NOT be written when keys are present: {text}"
+        );
+
+        // load() recovers the unit keys (and no VID).
+        let loaded = Mapfile::load(&p).unwrap();
+        assert_eq!(loaded.unit_keys(), keys.as_slice());
+        assert_eq!(loaded.vid(), None);
+        assert_eq!(loaded.entries(), mf.entries());
+
+        // VID-only path (no keys) still persists the VID as the retry marker.
+        let p2 = tmpfile("uk_vid_only");
+        let _ = std::fs::remove_file(&p2);
+        let mut mf2 = Mapfile::create(&p2, 1000, "test").unwrap();
+        mf2.set_vid([0xBB; 16]);
+        mf2.flush().unwrap();
+        let loaded2 = Mapfile::load(&p2).unwrap();
+        assert_eq!(loaded2.vid(), Some([0xBB; 16]));
+        assert!(loaded2.unit_keys().is_empty());
+        let _ = std::fs::remove_file(&p);
+        let _ = std::fs::remove_file(&p2);
+    }
+
     #[test]
     fn vid_round_trips_and_data_lines_unaffected() {
         let p = tmpfile("vid_round_trips");

src/disc/mod.rs

@@ -882,9 +882,9 @@ pub struct AacsState {
     /// Disc hash (SHA1 of Unit_Key_RO.inf) -- hex string with 0x prefix
     pub disc_hash: String,
     /// How keys were resolved
-    pub key_source: KeySource,
+    pub key_source: KeyOrigin,
     /// Volume Unique Key (16 bytes). `None` when keys were resolved
-    /// via the [`KeySource::KeyDbUnitKeys`] path — that source delivers
+    /// via the [`KeyOrigin::KeyDbUnitKeys`] path — that source delivers
     /// pre-decrypted unit keys without a VUK to derive them from.
     pub vuk: Option<[u8; 16]>,
     /// Decrypted unit keys (CPS unit number, key)
@@ -893,6 +893,13 @@ pub struct AacsState {
     pub read_data_key: Option<[u8; 16]>,
     /// Volume ID (16 bytes) -- from SCSI handshake
     pub volume_id: [u8; 16],
+    /// Raw `Unit_Key_RO.inf` bytes (encrypted unit keys + CPS map). Stashed at
+    /// scan so an external resolver (key-resolver) can derive the unit keys
+    /// from a VUK without re-reading the disc. Empty when not captured.
+    pub uk_ro: Vec<u8>,
+    /// Raw MKB bytes (`MKB_RO.inf`). Stashed at scan so an external resolver can
+    /// walk it (device/processing key → media key). Empty when not captured.
+    pub mkb: Vec<u8>,
 }
 
 /// How AACS keys were resolved. Variants are ordered root-of-trust →
@@ -900,7 +907,7 @@ pub struct AacsState {
 /// attempts derivation from the strongest input it has first and falls
 /// back toward pre-computed per-disc material.
 #[derive(Debug, Clone, Copy, PartialEq)]
-pub enum KeySource {
+pub enum KeyOrigin {
     /// MKB + device keys → subset-difference tree → VUK
     DeviceKey,
     /// MKB + processing keys → media key → VUK
@@ -917,74 +924,46 @@ pub enum KeySource {
     ExternalUk,
 }
 
-impl KeySource {
+impl KeyOrigin {
     pub fn name(&self) -> &'static str {
         match self {
-            KeySource::DeviceKey => "MKB + device key",
-            KeySource::ProcessingKey => "MKB + processing key",
-            KeySource::KeyDbDerived => "KEYDB (derived)",
-            KeySource::KeyDb => "KEYDB",
-            KeySource::KeyDbUnitKeys => "KEYDB (unit keys)",
-            KeySource::ExternalUk => "external UK",
+            KeyOrigin::DeviceKey => "MKB + device key",
+            KeyOrigin::ProcessingKey => "MKB + processing key",
+            KeyOrigin::KeyDbDerived => "KEYDB (derived)",
+            KeyOrigin::KeyDb => "KEYDB",
+            KeyOrigin::KeyDbUnitKeys => "KEYDB (unit keys)",
+            KeyOrigin::ExternalUk => "external UK",
         }
     }
 }
 
 // ─── Disc scanning ──────────────────────────────────────────────────────────
 
-/// Standard KEYDB.cfg search locations (compatible with libaacs).
-const KEYDB_SEARCH_PATHS: &[&str] = &[
-    ".config/aacs/KEYDB.cfg",    // libaacs standard path
-    ".config/freemkv/keydb.cfg", // freemkv download path
-];
-const KEYDB_SYSTEM_PATH: &str = "/etc/aacs/KEYDB.cfg";
-
-/// Options for disc scanning.
-#[derive(Default)]
-pub struct ScanOptions {
-    /// Path to KEYDB.cfg for AACS key lookup.
-    /// If None, searches standard locations ($HOME/.config/aacs/ and /etc/aacs/).
-    pub keydb_path: Option<std::path::PathBuf>,
-    /// Caller-supplied Unit Key — an alternative to keydb lookup. When set,
-    /// libfreemkv skips keydb lookup and all derivation and uses this key
-    /// directly to decrypt; it takes precedence over `keydb_path`. The caller
-    /// obtains the key however it likes; libfreemkv stays free of any network
-    /// dependency.
-    pub unit_key: Option<[u8; 16]>,
-    /// Disable KEYDB entirely: skip both the explicit `keydb_path` and the
-    /// standard-location search, so no keydb is loaded for this scan. A caller
-    /// that resolves keys out-of-band (e.g. a remote key service) sets this so
-    /// a keydb that merely happens to sit in a default location does not shadow
-    /// the out-of-band path. `unit_key` still takes precedence over everything.
-    pub disable_keydb: bool,
+/// AACS host credentials for the live-drive authenticated handshake.
+///
+/// Optional and source-agnostic: an unlocked / LibreDrive drive uses the OEM
+/// Volume-ID path and needs none, and an ISO scan has no handshake at all. The
+/// caller supplies the host cert(s) from wherever it likes — today the keydb's
+/// `host_certs()`, tomorrow a cert file or built-in. Decoupled from the key
+/// source: a locked drive needs the cert to unlock even when the decryption key
+/// comes from an online service.
+#[derive(Default, Clone)]
+pub struct DriveCredentials {
+    /// Host certificate(s) + private key(s) for the SCSI AACS handshake.
+    pub host_certs: Vec<crate::aacs::HostCert>,
 }
 
-impl ScanOptions {
-    /// Resolve KEYDB path: explicit path first, then standard locations.
-    /// Returns `None` when `disable_keydb` is set — no keydb is consulted.
-    fn resolve_keydb(&self) -> Option<std::path::PathBuf> {
-        if self.disable_keydb {
-            return None;
-        }
-        if let Some(p) = &self.keydb_path {
-            if p.exists() {
-                return Some(p.clone());
-            }
-        }
-        if let Some(home) = std::env::var_os("HOME").or_else(|| std::env::var_os("USERPROFILE")) {
-            for relative in KEYDB_SEARCH_PATHS {
-                let p = std::path::PathBuf::from(&home).join(relative);
-                if p.exists() {
-                    return Some(p);
-                }
-            }
-        }
-        let p = std::path::PathBuf::from(KEYDB_SYSTEM_PATH);
-        if p.exists() {
-            return Some(p);
-        }
-        None
-    }
+/// Options for disc scanning.
+///
+/// libfreemkv is lookup-free — it resolves no keys. The caller resolves a key
+/// out-of-band (a key source) and applies it via [`Disc::decrypt_with`]. The
+/// only scan input is the optional drive credentials for the live-drive
+/// authenticated handshake.
+#[derive(Default)]
+pub struct ScanOptions {
+    /// Host credentials for the live-drive AACS handshake. `None` for an
+    /// unlocked / LibreDrive drive (OEM Volume-ID path) and for ISO scans.
+    pub credentials: Option<DriveCredentials>,
 }
 
 /// Quick disc identification — name, format, capacity. No title/stream parsing.
@@ -1173,10 +1152,18 @@ impl Disc {
             .read_file(&mut reader, "/AACS/Unit_Key_RO.inf")
             .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/DUPLICATE/Unit_Key_RO.inf"))
             .map_err(|_| Error::AacsNoKeys)?;
-        let mkb = udf_fs
-            .read_file(&mut reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/MKB_RO.inf"))
+        // Prefer MKB_RO, fall back to MKB_RW, then TRIM to the real record
+        // length. Both files are allocated to a fixed ~128 MiB and zero-padded,
+        // so reading either ships up to ~124 MiB of nothing — trim to the
+        // record stream so callers send/store a few MB, not 128 MiB.
+        let mut mkb = udf_fs
+            .read_file(&mut reader, "/AACS/MKB_RO.inf")
+            .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/MKB_RW.inf"))
             .map_err(|_| Error::AacsNoKeys)?;
+        let n = crate::aacs::mkb_content_len(&mkb);
+        if n > 0 && n < mkb.len() {
+            mkb.truncate(n);
+        }
         Ok((inf, mkb))
     }
 
@@ -1191,10 +1178,18 @@ impl Disc {
             .read_file(&mut reader, "/AACS/Unit_Key_RO.inf")
             .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/DUPLICATE/Unit_Key_RO.inf"))
             .map_err(|_| Error::AacsNoKeys)?;
-        let mkb = udf_fs
-            .read_file(&mut reader, "/AACS/MKB_RW.inf")
-            .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/MKB_RO.inf"))
+        // Prefer MKB_RO, fall back to MKB_RW, then TRIM to the real record
+        // length. Both files are allocated to a fixed ~128 MiB and zero-padded,
+        // so reading either ships up to ~124 MiB of nothing — trim to the
+        // record stream so callers send/store a few MB, not 128 MiB.
+        let mut mkb = udf_fs
+            .read_file(&mut reader, "/AACS/MKB_RO.inf")
+            .or_else(|_| udf_fs.read_file(&mut reader, "/AACS/MKB_RW.inf"))
             .map_err(|_| Error::AacsNoKeys)?;
+        let n = crate::aacs::mkb_content_len(&mkb);
+        if n > 0 && n < mkb.len() {
+            mkb.truncate(n);
+        }
         Ok((inf, mkb))
     }
 
@@ -1210,7 +1205,7 @@ impl Disc {
         capacity: u32,
         handshake: Option<HandshakeResult>,
         handshake_error: Option<Error>,
-        opts: &ScanOptions,
+        _opts: &ScanOptions,
         udf_fs: udf::UdfFs,
     ) -> Result<Self> {
         // 2. Resolve encryption (AACS, CSS, or none)
@@ -1219,60 +1214,16 @@ impl Disc {
 
         let (aacs, aacs_error) = if !encrypted {
             (None, None)
-        } else if let Some(unit_key) = opts.unit_key {
-            // Second key source: caller supplied the Unit Key directly
-            // (external Unit Key). Skip keydb entirely.
-            match Self::resolve_encryption_static(&udf_fs, reader, unit_key, handshake.as_ref()) {
-                Ok(state) => (Some(state), None),
-                Err(e) => (None, Some(e)),
-            }
         } else {
-            match opts.resolve_keydb() {
-                Some(keydb_path) => {
-                    match Self::resolve_encryption(&udf_fs, reader, &keydb_path, handshake.as_ref())
-                    {
-                        Ok(state) => (Some(state), None),
-                        Err(e) => {
-                            // When the handshake itself failed AND resolution
-                            // bottomed out at "no keys", surface the upstream
-                            // handshake failure — it's more actionable than
-                            // the generic AacsNoKeys.
-                            let final_err = match (&e, handshake_error.as_ref()) {
-                                (
-                                    Error::AacsNoKeys
-                                    | Error::AacsVukNotInKeydb
-                                    | Error::AacsVidUnavailable,
-                                    Some(_),
-                                ) => handshake_error.unwrap(),
-                                _ => e,
-                            };
-                            tracing::warn!(
-                                target: "freemkv::disc",
-                                phase = "scan_aacs_resolve_failed",
-                                error_code = final_err.code(),
-                                keydb = %keydb_path.display(),
-                                handshake_ok = handshake.is_some(),
-                                "AACS key resolution failed"
-                            );
-                            (None, Some(final_err))
-                        }
-                    }
-                }
-                None => {
-                    tracing::warn!(
-                        target: "freemkv::disc",
-                        phase = "scan_aacs_no_keydb",
-                        "encrypted disc but no KEYDB found in search paths"
-                    );
-                    // Sentinel path string lets autorip's message switch
-                    // distinguish "no keydb found anywhere" from "keydb at
-                    // <path> failed to parse".
-                    let final_err =
-                        handshake_error.unwrap_or_else(|| crate::error::Error::KeydbLoad {
-                            path: String::from("<no keydb in search paths>"),
-                        });
-                    (None, Some(final_err))
-                }
+            // Lookup-free: capture the disc's AACS inputs (MKB, VID,
+            // Unit_Key_RO.inf) but resolve NO key. The caller resolves a Key
+            // from a key source and applies it via `Disc::decrypt_with`. The
+            // disc reports "encrypted, no keys" until then.
+            match Self::resolve_vid_only(&udf_fs, reader, handshake.as_ref()) {
+                Ok(state) => (Some(state), None),
+                // A handshake failure (no VID) is more actionable than the
+                // generic capture error, so surface it when present.
+                Err(e) => (None, Some(handshake_error.unwrap_or(e))),
             }
         };
 
@@ -1451,11 +1402,60 @@ impl Disc {
     }
 }
 
+/// A decryption key handed to libfreemkv by the caller.
+///
+/// libfreemkv is **lookup-free**: it never reads a keydb, never talks to a key
+/// server, never searches paths. The application resolves a key from whatever
+/// source it likes (a local keydb, an online key service, a mapfile cache) and
+/// hands it in here; libfreemkv uses it to decrypt, deriving any remaining
+/// AACS-chain steps it can from disc-read inputs (MKB / VID / `Unit_Key_RO.inf`).
+///
+/// `#[non_exhaustive]`: AACS is a derivation chain
+/// (`DK →(MKB)→ MK →(VID)→ VK →(Unit_Key_RO)→ UK`). Each variant is an entry
+/// point at one level of that chain; [`Disc::decrypt_with`] derives down from
+/// it to the per-CPS unit keys. New levels can be added without breaking
+/// callers.
+#[derive(Debug, Clone)]
+#[non_exhaustive]
+pub enum Key {
+    /// Device key(s) (AACS DK, positioned). libfreemkv walks the MKB
+    /// (subset-difference tree) to find the one that applies → media key →
+    /// VUK → unit keys. A source hands in its FULL device-key set, because
+    /// choosing which one applies *is* the MKB walk (derivation), and all
+    /// derivation lives here — never in a source.
+    Device(Vec<crate::aacs::keydb::DeviceKey>),
+    /// Processing key(s) (AACS PK). libfreemkv applies each against the MKB
+    /// → media key → VUK → unit keys.
+    Processing(Vec<[u8; 16]>),
+    /// Media key candidate(s) (Km). A source hands its full pool because an MK
+    /// is MKB-scoped (shared across a pressing/MKB family) — picking the one
+    /// that applies is `km_verifies` against this disc's MKB, which is
+    /// derivation, so it lives here. libfreemkv verifies, then derives the VUK
+    /// via the Volume ID and the per-CPS-unit keys.
+    Media(Vec<[u8; 16]>),
+    /// Volume Unique Key (VK / VUK). libfreemkv decrypts `Unit_Key_RO.inf`
+    /// into the per-CPS-unit keys. NOT terminal — the chain continues to the
+    /// unit keys.
+    Volume([u8; 16]),
+    /// Final per-CPS-unit AACS keys (`(cps_unit, 16-byte key)`). A key source
+    /// (keydb / key server) resolved these, or they were cached in the mapfile
+    /// at sweep; libfreemkv decrypts directly with no further derivation. This
+    /// is the terminal level every other variant derives down into.
+    Unit(Vec<(u32, [u8; 16])>),
+}
+
 impl Disc {
     /// Get the resolved decryption keys for this disc.
     /// Used by disc-to-ISO and other full-disc operations.
     pub fn decrypt_keys(&self) -> crate::decrypt::DecryptKeys {
         if let Some(ref aacs) = self.aacs {
+            // An AACS state with NO unit keys is "encrypted, no keys" — e.g.
+            // the VID-only state from out-of-band resolution before a Unit Key
+            // is supplied. Report None so callers treat it as missing keys
+            // (not a usable, empty key set).
+            if aacs.unit_keys.is_empty() {
+                return crate::decrypt::DecryptKeys::None;
+            }
             crate::decrypt::DecryptKeys::Aacs {
                 unit_keys: aacs.unit_keys.clone(),
                 read_data_key: aacs.read_data_key,
@@ -1469,6 +1469,152 @@ impl Disc {
         }
     }
 
+    /// Inject pre-resolved AACS unit keys into a scanned disc — the deferred-mux
+    /// / resume path. The keys come from the mapfile's `# freemkv-uk:` header
+    /// (persisted at sweep time when the disc was keyed), so the mux decrypts
+    /// directly with NO key-service round-trip. Populates `self.aacs.unit_keys`
+    /// so [`decrypt_keys`] returns them and marks the source `ExternalUk`.
+    ///
+    /// If the scan built no AACS state (`self.aacs == None`) — which happens
+    /// when the keydb was absent at scan time (`scan_aacs_no_keydb` →
+    /// `aacs_error = KeydbLoad`) — this synthesizes a minimal `ExternalUk`
+    /// state for an encrypted AACS disc. A Unit Key is the FINAL per-title
+    /// decryption key; the keydb is only needed to *derive* it, and that
+    /// derivation already happened at sweep (the UK is in the mapfile). So a UK
+    /// alone is sufficient to decrypt the on-disk ISO — AACS 2.0 bus decryption
+    /// was applied by the drive at read time, so `read_data_key` is unused for
+    /// file-backed mux. Without this, a keyed disc swept without a keydb would
+    /// recover its UK yet still report E8005 (no usable `decrypt_keys`) at
+    /// remux. No-op for an unencrypted or CSS (DVD) disc.
+    pub fn inject_unit_keys(&mut self, keys: Vec<(u32, [u8; 16])>) {
+        if let Some(aacs) = self.aacs.as_mut() {
+            aacs.unit_keys = keys;
+            aacs.key_source = KeyOrigin::ExternalUk;
+        } else if self.encrypted && self.css.is_none() {
+            self.aacs = Some(AacsState {
+                version: if self.format == DiscFormat::Uhd { 2 } else { 1 },
+                bus_encryption: self.format == DiscFormat::Uhd,
+                mkb_version: None,
+                disc_hash: String::new(),
+                key_source: KeyOrigin::ExternalUk,
+                vuk: None,
+                unit_keys: keys,
+                read_data_key: None,
+                volume_id: [0u8; 16],
+                uk_ro: Vec::new(),
+                mkb: Vec::new(),
+            });
+            // The prior resolution error (e.g. KeydbLoad) is now moot — we have
+            // the decryption key. Clear it so callers don't treat the disc as
+            // keyless on the stale error.
+            self.aacs_error = None;
+        }
+    }
+
+    /// The public AACS inputs for this disc, for a [`crate::KeySource`] to look
+    /// a key up. `None` when the disc carries no AACS state (unencrypted, CSS,
+    /// or AACS inputs not captured at scan). Contains no secrets — just disc
+    /// identity plus the on-disc AACS structures.
+    pub fn inputs(&self) -> Option<crate::keysource::DiscInputs> {
+        self.aacs.as_ref().map(|a| crate::keysource::DiscInputs {
+            disc_hash: a.disc_hash.clone(),
+            volume_id: a.volume_id,
+            mkb: a.mkb.clone(),
+            unit_key_ro: a.uk_ro.clone(),
+            // Content samples need the disc reader, which scan does not retain;
+            // the caller fills these for sources that validate against ciphertext.
+            samples: Vec::new(),
+        })
+    }
+
+    /// Apply a caller-resolved [`Key`] so [`Self::decrypt_keys`] yields usable
+    /// decryption state. **Lookup-free**: no keydb, no network — the caller
+    /// (an application, via a key source) does all resolution and hands the key
+    /// in here. For [`Key::Unit`] this is the deferred-mux / resume path: the
+    /// unit keys came from a key source or the mapfile cache, and libfreemkv
+    /// decrypts directly (see [`Self::inject_unit_keys`]).
+    pub fn decrypt_with(&mut self, key: Key) -> Result<()> {
+        // Unit keys are terminal — no derivation. Inject directly (resume /
+        // mapfile cache / a source that already had the final UKs).
+        if let Key::Unit(keys) = key {
+            self.inject_unit_keys(keys);
+            return Ok(());
+        }
+
+        // Every higher level derives DOWN to the unit keys, reusing the
+        // version-dispatched resolver — the single home for all AACS
+        // derivation (1.0 / 2.0 / 2.1 / 2.x). It needs the AACS inputs
+        // (Unit_Key_RO.inf, MKB, VID) stashed on the disc at scan time.
+        let aacs = self.aacs.as_ref().ok_or(crate::error::Error::AacsNoKeys)?;
+        if aacs.uk_ro.is_empty() {
+            // Scan captured no Unit_Key_RO.inf — nothing to derive into.
+            return Err(crate::error::Error::AacsNoKeys);
+        }
+
+        // Map the supplied Key -> raw material. The source handed in material
+        // at exactly one level; choosing/applying it is the resolver's job.
+        let mut supplied = crate::aacs::provider::SuppliedKey {
+            device_keys: Vec::new(),
+            processing_keys: Vec::new(),
+            media_keys: Vec::new(),
+            disc_entry: None,
+        };
+        match key {
+            Key::Device(dks) => supplied.device_keys = dks,
+            Key::Processing(pks) => supplied.processing_keys = pks,
+            Key::Media(mks) => supplied.media_keys = mks,
+            Key::Volume(vuk) => {
+                supplied.disc_entry = Some(crate::aacs::DiscEntry {
+                    disc_hash: aacs.disc_hash.clone(),
+                    title: String::new(),
+                    media_key: None,
+                    disc_id: None,
+                    vuk: Some(vuk),
+                    unit_keys: Vec::new(),
+                });
+            }
+            Key::Unit(_) => unreachable!("Key::Unit handled above"),
+        }
+
+        // Snapshot inputs (releases the &self borrow before the &mut below).
+        let volume_id = aacs.volume_id;
+        let mkb = aacs.mkb.clone();
+        let uk_ro = aacs.uk_ro.clone();
+        let version_u8 = aacs.version;
+
+        let provider_refs: [&dyn crate::aacs::KeyProvider; 1] = [&supplied];
+        let ctx = crate::aacs::ResolveContext {
+            unit_key_ro: &uk_ro,
+            content_cert: None,
+            volume_id: &volume_id,
+            providers: &provider_refs,
+            mkb: if mkb.is_empty() { None } else { Some(&mkb) },
+        };
+
+        // Version dispatch — V10 uses the classical resolver at 48-byte
+        // stride; V20/V21 share the 64-byte stride, so try the classical V20
+        // paths first and fall back to the 2.1 variant chain.
+        let resolved = match version_u8 {
+            1 => crate::aacs::resolve_keys_v1(&ctx),
+            _ => crate::aacs::resolve_keys_v2(&ctx).or_else(|| crate::aacs::resolve_keys_v21(&ctx)),
+        }
+        .ok_or(crate::error::Error::AacsKeyRejected)?;
+
+        if resolved.unit_keys.is_empty() {
+            return Err(crate::error::Error::AacsKeyRejected);
+        }
+
+        let a = self.aacs.as_mut().expect("aacs present (checked above)");
+        a.unit_keys = resolved.unit_keys;
+        if resolved.vuk.is_some() {
+            a.vuk = resolved.vuk;
+        }
+        a.key_source = KeyOrigin::ExternalUk;
+        // A prior scan-time resolution error (e.g. keyless scan) is now moot.
+        self.aacs_error = None;
+        Ok(())
+    }
+
     /// Copy disc sectors to an ISO image file.
     ///
     /// NOT a stream operation. Copies sectors byte-for-byte producing a valid
@@ -1554,6 +1700,7 @@ impl Disc {
             progress: opts.progress,
             halt: opts.halt.clone(),
             vid: opts.vid,
+            unit_keys: opts.unit_keys.clone(),
         };
         self.sweep(reader, path, &sweep_opts)
     }
@@ -1652,12 +1799,14 @@ impl Disc {
         )
         .map_err(|e| Error::IoError { source: e })?;
 
-        // Persist the disc's AACS Volume ID into the mapfile header so it
-        // survives to deferred-mux / resume. ddrescue-safe (comment line);
-        // does not touch the ISO payload. On a resume-load the VID is
-        // already present, but re-setting it (idempotent) covers the case
-        // where Pass 1 created the mapfile before the VID was known.
-        if let Some(vid) = opts.vid {
+        // Persist the disc's decryption state into the mapfile header so it
+        // survives to deferred-mux / resume. ddrescue-safe (comment lines);
+        // does not touch the ISO payload. KEYS XOR VID: a keyed disc writes its
+        // unit keys (the final answer — deferred-mux decrypts directly, no key
+        // service); an unresolved disc writes only the VID (the retry marker).
+        if !opts.unit_keys.is_empty() {
+            map.set_unit_keys(&opts.unit_keys);
+        } else if let Some(vid) = opts.vid {
             map.set_vid(vid);
         }
 
@@ -2136,7 +2285,15 @@ pub struct CopyOptions<'a> {
     /// Pass 1 so it survives to deferred-mux / resume. `None` for
     /// unencrypted / non-AACS discs. Caller wires this from
     /// `Disc::aacs.volume_id`.
+    ///
+    /// Persisted ONLY when `unit_keys` is empty (the disc didn't resolve a
+    /// key): the VID is the "still unresolved, retry-able" marker.
     pub vid: Option<[u8; 16]>,
+    /// Resolved AACS unit keys `(CPS unit, key)` to persist into the mapfile
+    /// during Pass 1. When non-empty these are written (the final answer, so
+    /// deferred-mux/resume decrypts directly) and the VID is NOT — keys XOR VID.
+    /// Caller wires this from `Disc::aacs.unit_keys`.
+    pub unit_keys: Vec<(u32, [u8; 16])>,
 }
 
 #[derive(Debug, Clone, Copy)]
@@ -2159,8 +2316,12 @@ pub struct SweepOptions<'a> {
     pub progress: Option<&'a dyn crate::progress::Progress>,
     pub halt: Option<std::sync::Arc<std::sync::atomic::AtomicBool>>,
     /// AACS Volume ID (16 bytes) persisted into the mapfile when the
-    /// sweep creates / opens it. `None` for unencrypted discs.
+    /// sweep creates / opens it. `None` for unencrypted discs. Written ONLY
+    /// when `unit_keys` is empty (keys XOR VID — the VID is the retry marker).
     pub vid: Option<[u8; 16]>,
+    /// Resolved AACS unit keys persisted into the mapfile when the sweep
+    /// creates / opens it. When non-empty these win over `vid`.
+    pub unit_keys: Vec<(u32, [u8; 16])>,
 }
 
 /// Options for [`Disc::patch`] (Pass N retry pass over bad ranges).
@@ -2655,6 +2816,229 @@ mod tests {
         }
     }
 
+    #[test]
+    fn inject_unit_keys_synthesizes_aacs_state_when_scan_built_none() {
+        // Regression (E8005 deferred-mux loop): a keyed AACS disc swept WITHOUT a
+        // keydb scans to aacs=None + aacs_error=KeydbLoad, but its UK is persisted
+        // in the mapfile. At remux the UK is recovered and injected — that MUST
+        // yield usable decrypt keys. Before the fix, inject_unit_keys no-op'd
+        // (no aacs to mutate), decrypt_keys stayed None, and the mux deferred
+        // forever with "No keys available (E8005)" despite holding the UK.
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        disc.aacs_error = Some(crate::error::Error::KeydbLoad {
+            path: "<no keydb in search paths>".into(),
+        });
+        assert!(
+            matches!(disc.decrypt_keys(), crate::decrypt::DecryptKeys::None),
+            "precondition: encrypted disc with no aacs state => no decrypt keys"
+        );
+
+        let uk = vec![(0u32, [0x11u8; 16])];
+        disc.inject_unit_keys(uk.clone());
+
+        match disc.decrypt_keys() {
+            crate::decrypt::DecryptKeys::Aacs {
+                unit_keys,
+                read_data_key,
+            } => {
+                assert_eq!(unit_keys, uk, "injected UK must be the decrypt key");
+                assert_eq!(read_data_key, None, "ISO mux needs no bus key");
+            }
+            _ => panic!("expected Aacs decrypt keys after injecting a UK"),
+        }
+        assert!(
+            disc.aacs_error.is_none(),
+            "stale KeydbLoad must be cleared once a UK is in hand"
+        );
+        assert_eq!(
+            disc.aacs.as_ref().unwrap().key_source,
+            KeyOrigin::ExternalUk
+        );
+    }
+
+    /// Build an AacsState carrying the given unit keys (other fields are inert
+    /// defaults — these tests only exercise the unit-key/decrypt-keys plumbing).
+    fn aacs_with(unit_keys: Vec<(u32, [u8; 16])>) -> AacsState {
+        AacsState {
+            version: 2,
+            bus_encryption: true,
+            mkb_version: None,
+            disc_hash: String::new(),
+            key_source: KeyOrigin::DeviceKey,
+            vuk: None,
+            unit_keys,
+            read_data_key: None,
+            volume_id: [0u8; 16],
+            uk_ro: Vec::new(),
+            mkb: Vec::new(),
+        }
+    }
+
+    #[test]
+    fn decrypt_keys_none_when_aacs_present_but_unit_keys_empty() {
+        // VID-only state (resolved but no Unit Key yet) must read as None, not
+        // an empty-but-usable key set — callers treat it as "keys missing".
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        disc.aacs = Some(aacs_with(Vec::new()));
+        assert!(matches!(
+            disc.decrypt_keys(),
+            crate::decrypt::DecryptKeys::None
+        ));
+    }
+
+    #[test]
+    fn decrypt_with_replaces_existing_aacs_unit_keys_and_marks_external() {
+        // When scan DID build an AACS state, decrypt_with must overwrite its
+        // unit keys (not append) and mark the source ExternalUk.
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        disc.aacs = Some(aacs_with(vec![(0, [0x01; 16])]));
+        let new = vec![(0u32, [0x77u8; 16]), (1, [0x88; 16])];
+        disc.decrypt_with(Key::Unit(new.clone())).unwrap();
+        match disc.decrypt_keys() {
+            crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } => {
+                assert_eq!(unit_keys, new, "must replace, preserving every CPS unit");
+            }
+            _ => panic!("expected Aacs decrypt keys"),
+        }
+        assert_eq!(
+            disc.aacs.as_ref().unwrap().key_source,
+            KeyOrigin::ExternalUk
+        );
+    }
+
+    /// Build a minimal valid `Unit_Key_RO.inf` carrying the given encrypted
+    /// unit keys at the V20 (64-byte) stride. Header is inert (no titles); only
+    /// the key-storage area matters for `parse_unit_key_ro`.
+    fn uk_ro_v20(enc_keys: &[[u8; 16]]) -> Vec<u8> {
+        let uk_pos = 32usize;
+        let keys_start = uk_pos + 48;
+        let stride = 64usize;
+        let mut data = vec![0u8; keys_start + enc_keys.len().max(1) * stride];
+        data[0..4].copy_from_slice(&(uk_pos as u32).to_be_bytes());
+        data[uk_pos..uk_pos + 2].copy_from_slice(&(enc_keys.len() as u16).to_be_bytes());
+        for (i, k) in enc_keys.iter().enumerate() {
+            let off = keys_start + i * stride;
+            data[off..off + 16].copy_from_slice(k);
+        }
+        data
+    }
+
+    #[test]
+    fn decrypt_with_volume_derives_per_cps_unit_keys() {
+        // A Volume key (VUK) is NOT terminal — the lib must decrypt
+        // Unit_Key_RO.inf into ONE unit key per CPS unit. Oracle = the lib's
+        // own decrypt_unit_key, so this pins the derive-down WIRING (Volume →
+        // per-CPS Unit), not the cipher.
+        let vuk = [0x5au8; 16];
+        let enc0 = [0x12u8; 16];
+        let enc1 = [0x34u8; 16];
+        let exp0 = crate::aacs::decrypt_unit_key(&vuk, &enc0);
+        let exp1 = crate::aacs::decrypt_unit_key(&vuk, &enc1);
+
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        let mut a = aacs_with(Vec::new());
+        a.uk_ro = uk_ro_v20(&[enc0, enc1]);
+        disc.aacs = Some(a);
+
+        disc.decrypt_with(Key::Volume(vuk)).unwrap();
+        match disc.decrypt_keys() {
+            crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } => {
+                assert_eq!(
+                    unit_keys,
+                    vec![(1u32, exp0), (2u32, exp1)],
+                    "VUK must decrypt EACH CPS unit's encrypted key (does not stop at VK)"
+                );
+            }
+            _ => panic!("expected Aacs decrypt keys after Volume-key derive-down"),
+        }
+        assert_eq!(
+            disc.aacs.as_ref().unwrap().key_source,
+            KeyOrigin::ExternalUk
+        );
+    }
+
+    #[test]
+    fn decrypt_with_higher_key_without_inputs_errors() {
+        // A non-Unit key needs the AACS inputs (Unit_Key_RO.inf) stashed at
+        // scan. Without them the lib cannot derive — surfaces AacsNoKeys, not a
+        // panic and not a silent keyless "success".
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        disc.aacs = Some(aacs_with(Vec::new())); // uk_ro empty
+        assert!(matches!(
+            disc.decrypt_with(Key::Volume([0x11u8; 16])).unwrap_err(),
+            crate::error::Error::AacsNoKeys
+        ));
+
+        // No AACS state at all → same.
+        let mut disc2 = make_test_disc(1000, "UHD");
+        disc2.encrypted = true;
+        assert!(matches!(
+            disc2
+                .decrypt_with(Key::Media(vec![[0x22u8; 16]]))
+                .unwrap_err(),
+            crate::error::Error::AacsNoKeys
+        ));
+    }
+
+    #[test]
+    fn decrypt_with_volume_yielding_no_units_is_rejected() {
+        // A key that produces zero unit keys (here: an empty key-storage area)
+        // is a rejection, not a silent empty success.
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        let mut a = aacs_with(Vec::new());
+        a.uk_ro = uk_ro_v20(&[]); // num_uk = 0
+        disc.aacs = Some(a);
+        assert!(matches!(
+            disc.decrypt_with(Key::Volume([0x11u8; 16])).unwrap_err(),
+            crate::error::Error::AacsKeyRejected
+        ));
+    }
+
+    #[test]
+    fn decrypt_with_unit_key_yields_decrypt_keys() {
+        // The public lookup-free entry point: hand libfreemkv a Key::Unit and
+        // decrypt_keys() must return usable AACS state (same path as the
+        // deferred-mux resume — autorip resolves the UK and passes it in).
+        let mut disc = make_test_disc(1000, "UHD");
+        disc.encrypted = true;
+        let uk = vec![(0u32, [0x44u8; 16])];
+        disc.decrypt_with(Key::Unit(uk.clone())).unwrap();
+        match disc.decrypt_keys() {
+            crate::decrypt::DecryptKeys::Aacs { unit_keys, .. } => {
+                assert_eq!(unit_keys, uk);
+            }
+            _ => panic!("expected Aacs decrypt keys after decrypt_with(Key::Unit)"),
+        }
+    }
+
+    #[test]
+    fn inject_unit_keys_is_noop_without_aacs_on_unencrypted_or_css() {
+        // Unencrypted disc: nothing to inject into, stays None.
+        let mut plain = make_test_disc(1000, "PLAIN");
+        plain.inject_unit_keys(vec![(0, [0x22; 16])]);
+        assert!(plain.aacs.is_none());
+        assert!(matches!(
+            plain.decrypt_keys(),
+            crate::decrypt::DecryptKeys::None
+        ));
+
+        // Encrypted CSS (DVD): an AACS UK must NOT synthesize an AACS state.
+        let mut dvd = make_test_disc(1000, "DVD");
+        dvd.format = DiscFormat::Dvd;
+        dvd.encrypted = true;
+        dvd.css = Some(crate::css::CssState {
+            title_key: [0u8; 5],
+        });
+        dvd.inject_unit_keys(vec![(0, [0x33; 16])]);
+        assert!(dvd.aacs.is_none(), "CSS disc must not gain an AACS state");
+    }
+
     #[test]
     fn sweep_to_dev_null_no_enodev() {
         let tmp = tempfile::tempdir().unwrap();
@@ -2672,6 +3056,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let result = disc.copy(&mut reader, &iso_path, &opts);
         assert!(
@@ -2697,6 +3082,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let result = disc.copy(&mut reader, std::path::Path::new("/dev/null"), &opts);
         assert!(
@@ -2728,6 +3114,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let result = disc.copy(&mut reader, std::path::Path::new("/dev/null"), &opts);
         assert!(
@@ -2758,6 +3145,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let sweep_result = disc.copy(&mut reader, &iso_path, &sweep_opts);
         assert!(
@@ -2776,6 +3164,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let patch_result = disc.copy(&mut reader2, &iso_path, &patch_opts);
         assert!(
@@ -2809,6 +3198,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let _sweep_result = disc.copy(&mut reader, &iso_path, &sweep_opts).unwrap();
 
@@ -2822,6 +3212,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let patch_result = disc.copy(&mut reader2, std::path::Path::new("/dev/null"), &patch_opts);
         assert!(
@@ -2855,6 +3246,7 @@ mod tests {
             progress: None,
             halt: None,
             vid: None,
+            unit_keys: Vec::new(),
         };
         let result = disc.copy(&mut reader, &iso_path, &opts);
         let r = result.expect("100-batch clean sweep should succeed");

src/keysource.rs

@@ -0,0 +1,69 @@
+//! Key sources — the lookup layer that hands libfreemkv a [`Key`].
+//!
+//! libfreemkv performs NO key lookup. An application resolves a key for a disc
+//! through one or more [`KeySource`]s, each a dumb adapter over a backing store
+//! (a keydb file, a key server, the mapfile cache): given the disc's
+//! [`DiscInputs`] it returns the raw [`Key`] at whatever level it holds. The
+//! library then derives down and decrypts via `Disc::decrypt_with`.
+//!
+//! Source implementations are published in the companion `freemkv-keysources`
+//! crate — keeping all key *policy* (which store, which order, online vs local)
+//! out of the library while all key *mechanism* (the AACS derivation chain)
+//! stays in it.
+
+use crate::disc::Key;
+use crate::error::Result;
+
+/// The public AACS inputs a key source needs to look a disc up. Captured at
+/// scan; contains no secrets — only the disc identity and the on-disc AACS
+/// structures a source or key server may key on.
+#[derive(Debug, Clone)]
+pub struct DiscInputs {
+    /// SHA-1 of `Unit_Key_RO.inf`, `0x`-prefixed hex. The value a keydb keys
+    /// its per-disc entries by, and a key server identifies the disc with.
+    pub disc_hash: String,
+    /// Volume ID (16 bytes). `[0u8; 16]` when no authenticated handshake ran
+    /// (e.g. an ISO/mapfile flow), which disables VID-keyed lookups.
+    pub volume_id: [u8; 16],
+    /// Raw MKB bytes. Empty when not captured.
+    pub mkb: Vec<u8>,
+    /// Raw `Unit_Key_RO.inf` bytes. Empty when not captured.
+    pub unit_key_ro: Vec<u8>,
+    /// Encrypted on-disc content sample units (each a 6144-byte aligned unit),
+    /// for sources that validate a key server-side against real ciphertext
+    /// (e.g. an online key service). Empty for sources that don't need them
+    /// (a local keydb). Populated by the application — reading content requires
+    /// the disc reader, which the library's scan does not retain — so
+    /// [`crate::Disc::inputs`] leaves it empty for the caller to fill.
+    pub samples: Vec<Vec<u8>>,
+}
+
+/// A key source: given a disc's [`DiscInputs`], offer candidate [`Key`]s.
+///
+/// Dumb by contract — a source queries its backing store and enumerates the raw
+/// material it holds as candidate keys at whatever level it has (device /
+/// processing / media / volume / unit). It performs NO AACS derivation and NO
+/// validation; `Disc::decrypt_with` derives down, and the caller validates by
+/// decrypting a sample. That keeps every derivation step in one place (the
+/// library) across AACS 1.0 / 2.0 / 2.1 / 2.x.
+///
+/// A source returns *multiple ordered candidates* because a single store can
+/// hold material for several derivation paths (a keydb has a per-disc VUK *and*
+/// a device-key pool *and* a media-key pool — the source can't know which
+/// applies without the MKB walk, which is derivation). The caller tries the
+/// candidates in order and keeps the first that decrypts (validate-before-
+/// return). A source that resolves server-side (an online key service) or holds
+/// a cached final key (the mapfile) simply returns one candidate.
+pub trait KeySource {
+    /// Candidate keys for this disc, most-specific first. Empty = this source
+    /// has nothing; `Err(_)` = the source itself failed (I/O, network, parse).
+    fn resolve(&self, inputs: &DiscInputs) -> Result<Vec<Key>>;
+
+    /// Whether this source needs [`DiscInputs::samples`] populated (encrypted
+    /// content samples) — true for a source that validates against ciphertext
+    /// server-side, false for one that keys purely on disc identity. The caller
+    /// reads samples (an extra disc read) only when some source needs them.
+    fn needs_samples(&self) -> bool {
+        false
+    }
+}

src/lib.rs

@@ -85,6 +85,7 @@ pub(crate) mod identity;
 pub(crate) mod ifo;
 pub mod io;
 pub mod keydb;
+pub mod keysource;
 pub mod labels;
 pub(crate) mod mpls;
 pub mod mux;
@@ -170,10 +171,11 @@ pub use decrypt::{DecryptKeys, decrypt_sectors, decrypt_threads, set_decrypt_thr
 // prefix at the crate root to keep both addressable.
 pub use disc::{
     AacsState, AudioChannels, AudioStream, Clip, Codec, ColorSpace, ContentFormat, DamageSeverity,
-    Disc, DiscFormat, DiscId, DiscTitle, Extent, FrameRate, HdrFormat, KeySource, LabelPurpose,
-    LabelQualifier, PatchOptions, PatchOutcome, Resolution, SampleRate, ScanOptions, Stream,
-    SubtitleStream, SweepOptions, VideoStream, classify_damage,
+    Disc, DiscFormat, DiscId, DiscTitle, DriveCredentials, Extent, FrameRate, HdrFormat, Key,
+    KeyOrigin, LabelPurpose, LabelQualifier, PatchOptions, PatchOutcome, Resolution, SampleRate,
+    ScanOptions, Stream, SubtitleStream, SweepOptions, VideoStream, classify_damage,
 };
+pub use keysource::{DiscInputs, KeySource};
 
 // ─── Streams ────────────────────────────────────────────────────────────────
 //

src/mux/resolve.rs

@@ -162,10 +162,11 @@ fn validate_network_addr(addr: &str) -> io::Result<()> {
 /// Options for opening an input stream.
 #[derive(Default)]
 pub struct InputOptions {
-    pub keydb_path: Option<String>,
-    /// Caller-supplied Unit Key (external Unit Key) — the second, mutually
-    /// exclusive key source. Takes precedence over `keydb_path`.
-    pub unit_key: Option<[u8; 16]>,
+    /// Caller-resolved per-CPS-unit AACS keys to apply to the scanned disc
+    /// (`(cps_unit, 16-byte key)`). Empty for an unencrypted disc or when the
+    /// caller has no key. The library does no lookup — a key source resolves
+    /// these and the caller passes them here.
+    pub unit_keys: Vec<(u32, [u8; 16])>,
     pub title_index: Option<usize>,
     /// Skip decryption — return raw encrypted bytes.
     pub raw: bool,
@@ -184,11 +185,6 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
         }
         StreamUrl::Iso { ref path } => {
             validate_file_path(path, "iso")?;
-            let scan_opts = crate::disc::ScanOptions {
-                keydb_path: opts.keydb_path.as_ref().map(Into::into),
-                unit_key: opts.unit_key,
-                ..Default::default()
-            };
             // FileSectorSource is the sole file-backed sector source.
             // It carries the platform-tuned SEQUENTIAL fadvise hint
             // (so the kernel readahead window widens) and the periodic
@@ -196,8 +192,19 @@ pub fn input(url: &str, opts: &InputOptions) -> io::Result<Box<dyn crate::pes::S
             // when the mux output is being written to the same disk.
             let mut reader = crate::io::file_sector_source::FileSectorSource::open(path)?;
             let capacity = reader.capacity_sectors();
-            let disc = crate::disc::Disc::scan_image(&mut reader, capacity, &scan_opts)
-                .map_err(|e| -> io::Error { e.into() })?;
+            let mut disc = crate::disc::Disc::scan_image(
+                &mut reader,
+                capacity,
+                &crate::disc::ScanOptions::default(),
+            )
+            .map_err(|e| -> io::Error { e.into() })?;
+            // Apply the caller-resolved keys (lookup-free); decrypt_keys() then
+            // yields them for the stream below. Propagate a failed application
+            // rather than silently muxing an undecryptable stream.
+            if !opts.unit_keys.is_empty() {
+                disc.decrypt_with(crate::disc::Key::Unit(opts.unit_keys.clone()))
+                    .map_err(|e| -> io::Error { e.into() })?;
+            }
             if disc.titles.is_empty() {
                 return Err(crate::error::Error::NoStreams.into());
             }

tests/crypto_tests.rs

@@ -89,8 +89,8 @@ fn aacs_decrypt_unit_roundtrip() {
         plain[offset] = 0x47; // TS sync byte
         offset += 192;
     }
-    // Set encryption flag (bits 6-7 of byte 0)
-    plain[0] |= 0xC0;
+    // No flag set: CBC-encrypting the body below scrambles packets 1..31's TS
+    // syncs, which is exactly what `is_aacs_scrambled` (raw-sync) detects.
 
     // Save original plaintext for comparison
     let expected = plain.clone();
@@ -126,8 +126,8 @@ fn aacs_decrypt_unit_roundtrip() {
         prev.copy_from_slice(&plain[off..off + 16]);
     }
 
-    // Verify it looks encrypted
-    assert!(aacs::is_unit_encrypted(&plain));
+    // Verify it looks encrypted (body TS syncs scrambled)
+    assert!(aacs::is_aacs_scrambled(&plain));
 
     // Now decrypt
     let result = aacs::decrypt_unit(&mut plain, &unit_key);
@@ -136,8 +136,8 @@ fn aacs_decrypt_unit_roundtrip() {
         "decrypt_unit should return true on valid encrypted unit"
     );
     assert!(
-        !aacs::is_unit_encrypted(&plain),
-        "encryption flag should be cleared"
+        !aacs::is_aacs_scrambled(&plain),
+        "decrypted unit should read as clear (TS syncs restored)"
     );
 
     // Verify TS sync bytes at expected positions (flag byte is cleared by decrypt)
@@ -156,17 +156,11 @@ fn aacs_decrypt_unit_roundtrip() {
         sync_count, expected_syncs
     );
 
-    // Compare all bytes except byte 0 (encryption flag cleared)
+    // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(
-        &plain[1..aacs::ALIGNED_UNIT_LEN],
-        &expected[1..aacs::ALIGNED_UNIT_LEN],
-        "decrypted unit body does not match original"
-    );
-    // Byte 0: original had 0xC0 set, decrypted has it cleared
-    assert_eq!(
-        plain[0] & !0xC0,
-        expected[0] & !0xC0,
-        "byte 0 mismatch ignoring flag"
+        &plain[..],
+        &expected[..],
+        "decrypted unit does not match original plaintext"
     );
 }
 
@@ -260,49 +254,65 @@ fn aacs_vuk_derivation_roundtrip() {
     assert_eq!(vuk, vuk2, "derive_vuk not deterministic");
 }
 
-/// Test: aacs_is_unit_encrypted detects encryption flags correctly.
+/// Test: aacs_is_aacs_scrambled detects scrambled units via the raw TS syncs.
 #[test]
-fn aacs_is_unit_encrypted_detection() {
-    let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];
-
+fn aacs_is_aacs_scrambled_detection() {
+    // A clear unit: TS sync (0x47) intact at every 192-byte packet → not
+    // scrambled. (Flag bits play no role.)
+    let mut clear = vec![0u8; aacs::ALIGNED_UNIT_LEN];
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        clear[off] = 0x47;
+        off += 192;
+    }
     assert!(
-        !aacs::is_unit_encrypted(&unit),
-        "zero unit should not be encrypted"
+        !aacs::is_aacs_scrambled(&clear),
+        "clear unit (syncs intact) must not be scrambled"
     );
 
-    unit[0] = 0x40; // bit 6 set
-    assert!(aacs::is_unit_encrypted(&unit));
+    // Flag bits do NOT make a synced unit look scrambled.
+    let mut flagged = clear.clone();
+    flagged[0] = 0xC0; // copy-control bits
+    flagged[7] = 0xC0; // TSC bits
+    assert!(
+        !aacs::is_aacs_scrambled(&flagged),
+        "flag bits must not be read as encryption"
+    );
 
-    unit[0] = 0x80; // bit 7 set
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    unit[0] = 0xC0; // both bits set
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    unit[0] = 0x3F; // bits 6-7 clear
-    assert!(!aacs::is_unit_encrypted(&unit));
+    // A scrambled body (syncs destroyed) → scrambled.
+    let scrambled = vec![0x99u8; aacs::ALIGNED_UNIT_LEN];
+    assert!(
+        aacs::is_aacs_scrambled(&scrambled),
+        "unit with no intact TS syncs must read as scrambled"
+    );
 
     // Too short
-    let short = vec![0xC0u8; 100];
+    let short = vec![0xFFu8; 100];
     assert!(
-        !aacs::is_unit_encrypted(&short),
+        !aacs::is_aacs_scrambled(&short),
         "short buffer should not be detected"
     );
 }
 
 /// Test: aacs_decrypt_unit_unencrypted_passthrough
 ///
-/// A unit without encryption flags should pass through decrypt_unit unchanged.
+/// A clear unit (TS syncs intact) should pass through decrypt_unit unchanged.
 #[test]
 fn aacs_decrypt_unit_unencrypted_passthrough() {
     let mut unit = vec![0x42u8; aacs::ALIGNED_UNIT_LEN];
-    unit[0] = 0x00; // no encryption flag
+    // Intact TS syncs every 192 bytes → not scrambled → passthrough.
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        unit[off] = 0x47;
+        off += 192;
+    }
     let original = unit.clone();
     let key = [0xAA; 16];
 
+    assert!(!aacs::is_aacs_scrambled(&unit));
     let result = aacs::decrypt_unit(&mut unit, &key);
-    assert!(result, "unencrypted unit should return true");
-    assert_eq!(unit, original, "unencrypted unit should be unchanged");
+    assert!(result, "clear unit should return true");
+    assert_eq!(unit, original, "clear unit should be unchanged");
 }
 
 // ── AACS cross-validation with independent AES implementation ──────────────
@@ -369,8 +379,7 @@ fn aacs_cross_validation_encrypt_then_decrypt() {
             plaintext[i] = (i % 251) as u8;
         }
     }
-    // Set encryption flag
-    plaintext[0] = 0xC0;
+    // No flag set: the CBC-encrypted body scrambles the packet syncs.
 
     let expected = plaintext.clone();
 
@@ -401,14 +410,11 @@ fn aacs_cross_validation_encrypt_then_decrypt() {
         ok,
         "decrypt_unit returned false (TS sync verification failed)"
     );
-    assert_eq!(plaintext[0] & 0xC0, 0x00, "encryption flag not cleared");
 
-    // Compare (byte 0 flag was cleared)
-    let mut expected_cleared = expected.clone();
-    expected_cleared[0] &= !0xC0;
+    // Decryption clears no flag, so the unit round-trips byte-for-byte.
     assert_eq!(
-        &plaintext[1..aacs::ALIGNED_UNIT_LEN],
-        &expected_cleared[1..aacs::ALIGNED_UNIT_LEN],
+        &plaintext[..],
+        &expected[..],
         "decrypted unit does not match original plaintext"
     );
 }
@@ -428,7 +434,7 @@ fn aacs_cross_validation_alternate_key() {
         plaintext[off] = 0x47;
         off += 192;
     }
-    plaintext[0] = 0xC0;
+    // No flag set: the CBC-encrypted body scrambles the packet syncs.
     let expected = plaintext.clone();
 
     let mut header = [0u8; 16];
@@ -446,12 +452,8 @@ fn aacs_cross_validation_alternate_key() {
 
     assert!(aacs::decrypt_unit(&mut plaintext, &unit_key));
 
-    let mut expected_cleared = expected;
-    expected_cleared[0] &= !0xC0;
-    assert_eq!(
-        &plaintext[1..aacs::ALIGNED_UNIT_LEN],
-        &expected_cleared[1..aacs::ALIGNED_UNIT_LEN],
-    );
+    // Decryption clears no flag, so the unit round-trips byte-for-byte.
+    assert_eq!(&plaintext[..], &expected[..]);
 }
 
 /// Verify that `decrypt_bus` correctly reverses AES-CBC encryption applied

tests/disc_tests.rs

@@ -126,31 +126,19 @@ fn disc_title_total_sectors() {
 // ── ScanOptions tests ──────────────────────────────────────────────────────
 
 #[test]
-fn scan_options_default() {
+fn scan_options_default_has_no_credentials() {
+    // Lookup-free: the only scan input is the optional live-drive credentials.
     let opts = ScanOptions::default();
-    assert!(opts.keydb_path.is_none());
+    assert!(opts.credentials.is_none());
 }
 
 #[test]
-fn scan_options_with_keydb() {
+fn scan_options_with_credentials() {
     let opts = ScanOptions {
-        keydb_path: Some(("/tmp/KEYDB.cfg").into()),
-        ..Default::default()
+        credentials: Some(libfreemkv::DriveCredentials::default()),
     };
-    assert_eq!(
-        opts.keydb_path.as_ref().unwrap().to_str().unwrap(),
-        "/tmp/KEYDB.cfg"
-    );
-}
-
-#[test]
-fn scan_options_with_keydb_pathbuf() {
-    let path = std::path::PathBuf::from("/home/user/.config/aacs/KEYDB.cfg");
-    let opts = ScanOptions {
-        keydb_path: Some(path.clone()),
-        ..Default::default()
-    };
-    assert_eq!(opts.keydb_path.unwrap(), path);
+    assert!(opts.credentials.is_some());
+    assert!(opts.credentials.unwrap().host_certs.is_empty());
 }
 
 // ── detect_format integration tests ───────────────────────────────────────
@@ -511,21 +499,16 @@ fn batch_count_max_batch_sizes() {
 }
 
 #[test]
-fn resolve_encryption_no_keydb() {
-    // A UDF image with /AACS directory but no keydb path -> aacs is None
+fn scan_encrypted_resolves_no_keys() {
+    // A UDF image with an /AACS directory: the lookup-free scan detects
+    // encryption and captures inputs, but resolves NO key on its own — a
+    // caller applies one later via Disc::decrypt_with.
     let mut reader = MockSectorReader::new();
     build_udf_with_aacs_dir(&mut reader);
 
-    // No keydb configured and no standard keydb on the system
-    let opts = ScanOptions {
-        keydb_path: Some(("/nonexistent/path/KEYDB.cfg").into()),
-        ..Default::default()
-    };
-    let disc = Disc::scan_image(&mut reader, 1000, &opts).unwrap();
+    let disc = Disc::scan_image(&mut reader, 1000, &ScanOptions::default()).unwrap();
 
-    // The disc detects encryption but can't resolve keys without a keydb
-    assert!(
-        disc.aacs.is_none(),
-        "aacs should be None when keydb is unavailable"
-    );
+    // No unit keys without an external key (the mock has no Unit_Key_RO.inf to
+    // capture, so the keyless state isn't even built) — either way, no keys.
+    assert!(matches!(disc.decrypt_keys(), libfreemkv::DecryptKeys::None));
 }

tests/pass_n_patch_fix.rs

@@ -82,22 +82,24 @@ fn decrypt_sectors_with_css_keys_works() {
 /// Test: AACS unit encryption detection works.
 #[test]
 fn aacs_encryption_flag_detection() {
+    // A clear unit: TS syncs (0x47) intact at every 192-byte packet.
     let mut unit = vec![0u8; aacs::ALIGNED_UNIT_LEN];
+    let mut off = 4;
+    while off < aacs::ALIGNED_UNIT_LEN {
+        unit[off] = 0x47;
+        off += 192;
+    }
+    // Encryption is the scrambled body (TS syncs destroyed), NOT a flag bit.
+    assert!(!aacs::is_aacs_scrambled(&unit));
 
-    // No encryption flag
-    assert!(!aacs::is_unit_encrypted(&unit));
-
-    // Set bit 6
-    unit[0] |= 0x40;
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    // Set bit 7
-    unit[0] = 0x80;
-    assert!(aacs::is_unit_encrypted(&unit));
-
-    // Both bits set
+    // Flag bits on a synced unit do not make it look encrypted.
     unit[0] = 0xC0;
-    assert!(aacs::is_unit_encrypted(&unit));
+    unit[7] = 0xC0;
+    assert!(!aacs::is_aacs_scrambled(&unit));
+
+    // Scrambled body (syncs gone) → encrypted.
+    let scrambled = vec![0x99u8; aacs::ALIGNED_UNIT_LEN];
+    assert!(aacs::is_aacs_scrambled(&scrambled));
 }
 
 /// Test: DecryptKeys::is_encrypted() correctly identifies encrypted state.