Raise keydb size cap 64 MiB -> 128 MiB

The public UHD keydb (fvonline) is ~62 MiB and growing, leaving only ~2 MiB
under the old 64 MiB ceiling — updates would start failing as it grows.
128 MiB restores years of headroom while still bounding a decompression
bomb. Both cap sites (keydb.rs download/save, keydb_format.rs on-disk load)
bumped; the unrelated MKB cap in online.rs is untouched.

CHANGELOG.md

@@ -1,5 +1,90 @@
 # Changelog
 
+## [1.6.0] — UNRELEASED
+
+Version sync with the workspace (freemkv-engine split release). No source change
+in this crate; it remains a pluggable AACS key-source provider consumed by the
+`freemkv` CLI and libfreemkv's key resolver.
+
+## [1.5.2] — 2026-07-22
+
+Version sync with the workspace; inherits libfreemkv 1.5.2 (CSS DVD descramble
+fix). No source change in this crate.
+
+## [1.4.5] — 2026-07-18
+
+Version sync; inherits libfreemkv 1.4.5. `KeySource` split into `get_unit_keys` +
+`get_fmts_indexes`, and a keydb device-key parse bug on an uppercase `0X` hex
+prefix was fixed (case-insensitive hex parsing across the toolchain).
+
+## [1.4.4] — 2026-07-17
+
+Version sync; inherits libfreemkv 1.4.4. The online `/decode` request is built from
+a `DecodeSampleSet` proven sufficient by type rather than a runtime length check.
+
+## [1.4.3] — 2026-07-17
+
+Version sync; inherits libfreemkv 1.4.3. The online unit-key reply is parsed as a
+list (one key for an ordinary disc, the ordered set for a forensic-variant disc),
+and `MIN_SAMPLE_UNITS` is re-exported from libfreemkv.
+
+## [1.4.2] — 2026-07-15
+
+Version sync with the workspace; inherits libfreemkv 1.4.2. The keydb test that
+feeds real key material into the AACS crypto was adapted to the segregated
+`decrypt_unit` + `is_clean` primitives (behaviour unchanged).
+
+## [1.4.1] — 2026-07-14
+
+Version sync with the workspace; inherits libfreemkv 1.4.1.
+
+## [1.4.0] — 2026-07-13
+
+Version sync with the workspace; inherits libfreemkv 1.4.0.
+
+## [1.3.2] — 2026-07-10
+
+### Changed
+
+- Unit keys carry libfreemkv's new `UnitKey.variant_number`; every source
+  (keydb, online, VUK-derived) emits `0` — ordinary, non-forensic content —
+  via the `UnitKey::new` constructor. No behaviour change. Inherits
+  **libfreemkv 1.3.2**.
+
+## [1.3.1] — 2026-07-10
+
+### Licensing
+
+- **Relicensed to the MIT License, from 1.3.1 onwards** (releases up to and
+  including 1.3.0 remain under AGPL-3.0).
+
+Version sync with the workspace; inherits libfreemkv 1.3.1.
+
+## [1.3.0] — 2026-07-08
+
+### Added
+
+- **AACS 2.0 host certs round-trip through `keydb.cfg`.** `to_keydb_cfg` now
+  emits the sibling `| HC2 |` line — the inverse of the v2 host-cert parser — so
+  writing a keydb back out no longer silently drops AACS 2.0 host certs.
+
+### Changed
+
+- **Resolve runs directly on `libfreemkv::aacs` primitives.** After libfreemkv
+  dropped its `aacs::boil` veneer, the resolve path now calls
+  `derive_media_key_from_{pk,dk}`, `derive_vuk`, and `decrypt_unit_key` from
+  `aacs::derive` with the `aacs::types` newtypes. No behaviour change.
+- Inherits **libfreemkv 1.3.0**.
+
+### Fixed
+
+- **keydb save-validation matches the parser exactly.** A `0x` line counts as a
+  disc entry only when it also contains ` = `, so validating and persisting
+  content that parses to zero usable entries (e.g. a stray `0xDEADBEEF` line) can
+  no longer succeed.
+- **Disc-entry titles round-trip verbatim** (parentheses and all) — the parse
+  path now keeps the title exactly as the emit path writes it.
+
 ## [1.2.0] — 2026-06-29
 
 ### Changed

Cargo.toml

@@ -1,10 +1,10 @@
 [package]
 name = "freemkv-keysources"
-version = "1.2.2"
+version = "1.6.0"
 edition = "2024"
 rust-version = "1.86"
-license = "AGPL-3.0-only"
-description = "Pluggable AACS key sources (keydb, online key service) for libfreemkv. Each source looks a disc up and hands libfreemkv its terminal Unit Keys via get_uk; the library does all derivation."
+license = "MIT"
+description = "Pluggable AACS key sources (keydb, online key service) for libfreemkv. Each source looks a disc up and hands libfreemkv its terminal Unit Keys via get_unit_keys; the library does all derivation."
 repository = "https://github.com/freemkv/freemkv-keysources"
 keywords = ["aacs", "blu-ray", "uhd", "decryption", "keydb"]
 categories = ["multimedia"]
@@ -17,7 +17,7 @@ publish = false
 # The crate provides the `KeySource` trait + `Key`/`DiscInputs` types these impls fill.
 # libfreemkv is git-only now; the committed [patch.crates-io] below redirects this
 # bare version req to the libfreemkv git tag (local dev overrides it to a path).
-libfreemkv = "1.2"
+libfreemkv = "1.5"
 # OnlineSource: POST disc inputs + samples to a key service over HTTP.
 ureq = { version = "2", features = ["json"] }
 serde_json = "1"
@@ -34,10 +34,10 @@ tracing = "0.1"
 lto = "thin"
 codegen-units = 1
 
-# libfreemkv is git-only (off crates.io). Redirect the bare `libfreemkv = "1.2"`
+# libfreemkv is git-only (off crates.io). Redirect the bare `libfreemkv = "1.5"`
 # req above to the git tag — committed and CI-visible. The release script
 # rewrites this tag to the new version before regenerating Cargo.lock. Local dev
 # overrides it with a path patch via the gitignored .cargo/config.toml (a
 # config-level [patch.crates-io] wins over this manifest one for the same crate).
 [patch.crates-io]
-libfreemkv = { git = "https://github.com/freemkv/libfreemkv", tag = "v1.2.2" }
+libfreemkv = { git = "https://github.com/freemkv/libfreemkv", tag = "v1.5.2" }

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Matthew Jackson & Contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

src/keydb.rs

@@ -41,9 +41,11 @@ use libfreemkv::{Error, KeySource};
 use crate::keydb_format::KeyDb;
 
 /// Upper bound on decompressed keydb size. The published keydb is a few MiB;
-/// 64 MiB is a generous ceiling that still caps a decompression bomb (a tiny
-/// zip/gz can otherwise inflate to GiB and OOM the daily refresh thread).
-const MAX_KEYDB_BYTES: u64 = 64 * 1024 * 1024;
+/// 128 MiB is a generous ceiling that still caps a decompression bomb (a tiny
+/// zip/gz can otherwise inflate to GiB and OOM the daily refresh thread). The
+/// public UHD keydb (fvonline) is ~62 MiB and growing, so 64 MiB was getting
+/// tight; 128 MiB leaves years of headroom.
+const MAX_KEYDB_BYTES: u64 = 128 * 1024 * 1024;
 
 /// Result of a KEYDB save/update -- path written, entry count, and byte size.
 #[derive(Debug)]
@@ -90,7 +92,11 @@ impl KeydbSource {
             .lines()
             .filter(|l| {
                 let t = l.trim();
-                t.starts_with("0x")
+                // Mirror KeyDb::parse's disc-entry rule EXACTLY (keydb_format.rs:
+                // a "0x" line is only an entry if it also contains " = "), so
+                // save() never validates + persists content that parses to zero
+                // usable entries (e.g. a stray "0xDEADBEEF" comment line).
+                (t.starts_with("0x") && t.contains(" = "))
                     || t.starts_with("| DK")
                     || t.starts_with("| PK")
                     || t.starts_with("| HC")
@@ -180,10 +186,7 @@ impl KeydbSource {
         // 1. Terminal Unit Keys stored in the entry — directly usable, no
         //    derivation. Preserve the keydb's CPS numbering (idx = num - 1).
         for (num, key) in &entry.unit_keys {
-            keys.push(UnitKey {
-                idx: num.saturating_sub(1),
-                key: *key,
-            });
+            keys.push(UnitKey::new(num.saturating_sub(1), *key));
         }
 
         // The disc's encrypted title keys (from Unit_Key_RO.inf) — what every
@@ -327,10 +330,14 @@ fn write_atomic(path: &Path, text: &str) -> Result<(), Error> {
 }
 
 impl KeySource for KeydbSource {
-    /// Resolve this disc's terminal Unit Keys from the keydb. A missing /
+    /// Resolve this disc's base per-CPS-unit Unit Keys from the keydb. A missing /
     /// unreadable keydb is not an error — it simply yields no keys (another
     /// source may have them), the same as the library's own loader.
-    fn get_uk(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, Error> {
+    ///
+    /// The keydb carries no AACS 2.1 forensic index keys today, so it does not
+    /// override `get_fmts_indexes` — the default (empty) opts it out, and an FMTS
+    /// disc's forensic set comes from the online source.
+    fn get_unit_keys(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, Error> {
         match KeyDb::load(&self.path) {
             Ok(db) => Ok(Self::unit_keys_from(&db, ctx)),
             Err(_) => Ok(Vec::new()),
@@ -362,7 +369,7 @@ mod tests {
     use libfreemkv::aacs::types::DeviceKey;
     use std::collections::HashMap;
 
-    // ── A test ResolveCtx, so get_uk's path selection can be exercised without
+    // ── A test ResolveCtx, so get_unit_keys's path selection can be exercised without
     //    a real Disc. Each accessor returns exactly what a case needs. ──────────
     struct MockCtx {
         disc_hash: String,
@@ -747,7 +754,7 @@ mod tests {
     fn get_uk_missing_keydb_is_ok_empty() {
         let src = KeydbSource::new("/nonexistent/path/keydb.cfg");
         let got = src
-            .get_uk(&ctx(HASH, Vec::new(), None))
+            .get_unit_keys(&ctx(HASH, Vec::new(), None))
             .expect("missing keydb is not an error");
         assert!(got.is_empty());
     }
@@ -814,7 +821,7 @@ mod tests {
         let target = dir.join("nested").join("mykeys.cfg");
         let src = KeydbSource::new(&target);
 
-        let body = b"0xDEADBEEFDEADBEEFDEADBEEFDEADBEEF\n";
+        let body = b"0xDEADBEEFDEADBEEFDEADBEEFDEADBEEF = Test\n";
         let result = src.save(body).expect("save must succeed");
 
         assert_eq!(
@@ -840,9 +847,9 @@ mod tests {
         let target = dir.join("k.cfg");
         let src = KeydbSource::new(&target);
 
-        let body = b"0xAABBCCDDAABBCCDDAABBCCDDAABBCCDD\n".to_vec();
+        let body = b"0xAABBCCDDAABBCCDDAABBCCDDAABBCCDD = Test\n".to_vec();
         let result = src
-            .update(|_url| Ok(body.clone()), "http://example.invalid/keydb.zip")
+            .update(|_url| Ok(body.clone()), "http://example.test/keydb.zip")
             .expect("update must succeed with a good fetch");
 
         assert_eq!(result.path, target, "update must save to the source's path");

src/keydb_format.rs

@@ -23,9 +23,10 @@ use libfreemkv::aacs::types::{DeviceKey, HostCert};
 pub type NumberedUnitKey = (u32, [u8; 16]);
 
 /// Upper bound on the on-disk keydb.cfg size accepted by [`KeyDb::load`].
-/// The real public UHD keydb is a few MiB; 64 MiB is generous headroom while
-/// still bounding the worst-case allocation from a hostile/corrupt file.
-const MAX_KEYDB_BYTES: u64 = 64 * 1024 * 1024;
+/// The public UHD keydb (fvonline) is ~62 MiB and growing; 128 MiB is generous
+/// headroom while still bounding the worst-case allocation from a hostile or
+/// corrupt file.
+const MAX_KEYDB_BYTES: u64 = 128 * 1024 * 1024;
 
 /// Upper bound on parsed disc entries. The real public keydb carries
 /// ~170k+ entries, so the cap sits well above that while still bounding
@@ -390,6 +391,8 @@ impl KeyDb {
         let mut out = String::new();
 
         // Host certs (AACS 1.0): | HC | HOST_PRIV_KEY 0x.. | HOST_CERT 0x.. ; Revoked in MKBv<N>
+        // AACS 2.0 credentials ride a sibling `| HC2 |` line; emit it too so a
+        // round-trip through `to_keydb_cfg` never silently drops v2 host certs.
         for hc in &self.host_certs {
             out.push_str("| HC | HOST_PRIV_KEY 0x");
             out.push_str(&hx(&hc.cert.private_key));
@@ -400,6 +403,17 @@ impl KeyDb {
                 out.push_str(&n.to_string());
             }
             out.push('\n');
+            // AACS 2.0 (HC2): inverse of `parse_host_cert_v2`.
+            if let (Some(pk2), Some(cert2)) = (
+                hc.cert.private_key_v2.as_ref(),
+                hc.cert.certificate_v2.as_ref(),
+            ) {
+                out.push_str("| HC2 | HOST_PRIV_KEY 0x");
+                out.push_str(&hx(pk2));
+                out.push_str(" | HOST_CERT 0x");
+                out.push_str(&hx(cert2));
+                out.push('\n');
+            }
         }
 
         // Device keys: | DK | DEVICE_KEY 0x.. | DEVICE_NODE 0x.. | KEY_UV 0x.. | KEY_U_MASK_SHIFT 0x..
@@ -429,9 +443,8 @@ impl KeyDb {
             // `0x` would double it on re-parse).
             out.push_str(h);
             out.push_str(" = ");
-            // Parse stores the display title (inside parens) or the whole string
-            // when there are none; emitting the stored title bare round-trips
-            // (no parens → parser keeps it verbatim). Empty → "Unknown".
+            // Parse stores the title VERBATIM (parens and all), so emitting it
+            // bare round-trips through parse. Empty → "Unknown".
             if d.title.is_empty() {
                 out.push_str("Unknown");
             } else {
@@ -494,9 +507,12 @@ impl KeyDb {
 
         Some(DeviceKey {
             key: parse_hex16(key_str)?,
-            node: u16::from_str_radix(node_str.trim_start_matches("0x"), 16).ok()?,
-            uv: u32::from_str_radix(uv_str.trim_start_matches("0x"), 16).ok()?,
-            u_mask_shift: u8::from_str_radix(shift_str.trim_start_matches("0x"), 16).ok()?,
+            // Canonical hex parsers (one prefix/case rule for the whole workspace)
+            // — NOT an ad-hoc `from_str_radix(trim_start_matches("0x"))`, whose
+            // case-sensitive strip silently dropped an uppercase-`0X` value.
+            node: libfreemkv::hex::parse_hex_u16(node_str)?,
+            uv: libfreemkv::hex::parse_hex_u32(uv_str)?,
+            u_mask_shift: libfreemkv::hex::parse_hex_u8(shift_str)?,
         })
     }
 
@@ -1096,8 +1112,8 @@ mod tests {
 
     #[test]
     fn disc_entry_malformed_parens_falls_back_to_whole_title() {
-        // ')' before '(' would make start+1 > end; the guarded get() returns
-        // None and the parser falls back to the whole title (no panic).
+        // The title is kept verbatim regardless of paren placement — a malformed
+        // ')' before '(' is not special-cased; the whole string is the title.
         let line = "0x00 = FILM) (X | M | 0x".to_string() + &"00".repeat(16);
         let e = KeyDb::parse_disc_entry(&line).unwrap();
         assert_eq!(e.title, "FILM) (X");
@@ -1207,6 +1223,20 @@ mod tests {
         assert!(db.processing_keys.is_empty());
     }
 
+    #[test]
+    fn parse_device_key_accepts_uppercase_0x_prefix() {
+        // Regression: node/uv/shift parsed via a case-sensitive
+        // `trim_start_matches("0x")`, so an uppercase `0X` prefix was not
+        // stripped, `from_str_radix` failed, and the WHOLE device key was
+        // silently dropped. All four fields must parse regardless of prefix case.
+        let line = "| DK | DEVICE_KEY 0x000102030405060708090A0B0C0D0E0F \
+                    | DEVICE_NODE 0X0001 | KEY_UV 0X00000002 | KEY_U_MASK_SHIFT 0X03";
+        let dk = KeyDb::parse_device_key(line).expect("uppercase 0X prefix must parse");
+        assert_eq!(dk.node, 1);
+        assert_eq!(dk.uv, 2);
+        assert_eq!(dk.u_mask_shift, 3);
+    }
+
     #[test]
     fn parse_host_cert_v2_rejects_wrong_priv_len_and_short_cert() {
         // v2 priv must be exactly 32 bytes; cert must be >= 132.
@@ -1400,7 +1430,7 @@ mod tests {
     //
     // These exercise the parser (KeyDb::load) end-to-end against a real
     // keydb.cfg and feed its material into libfreemkv's AACS crypto
-    // (derive_vuk / decrypt_unit_try_keys). They live here now that the
+    // (derive_vuk, then decrypt_unit + is_clean_ts). They live here now that the
     // parser lives here. All are KEYDB_PATH-env-gated and no-op in CI when
     // the env is unset; they must still COMPILE.
     // ════════════════════════════════════════════════════════════════════
@@ -1454,7 +1484,7 @@ mod tests {
         let original = std::fs::read(&unit_path).unwrap();
         assert_eq!(original.len(), libfreemkv::aacs::content::ALIGNED_UNIT_LEN);
         assert!(
-            libfreemkv::aacs::content::ts_sync_destroyed(&original),
+            !libfreemkv::aacs::content::is_clean(&original, libfreemkv::disc::ContentFormat::BdTs),
             "Unit should be encrypted"
         );
 
@@ -1473,20 +1503,20 @@ mod tests {
 
         eprintln!("Found {} entries with unit keys", candidate_entries.len());
 
-        // Try each entry's unit keys
+        // Try each entry's unit keys: apply the key, then ask whether it opened
+        // the unit (the segregated primitives — decrypt, then structural check).
         for entry in &candidate_entries {
-            let keys: Vec<[u8; 16]> = entry.unit_keys.iter().map(|(_, k)| *k).collect();
-            let mut unit = original.clone();
-
-            if let Some(res) = libfreemkv::aacs::content::decrypt_unit_try_keys(&mut unit, &keys) {
-                eprintln!(
-                    "SUCCESS: Decrypted with entry {} ({res:?})",
-                    entry.disc_hash
-                );
-                // Count TS sync bytes
-                let ts = (0..32).filter(|&i| unit[4 + i * 192] == 0x47).count();
-                eprintln!("  TS sync bytes: {}/32", ts);
-                return;
+            for (_, key) in &entry.unit_keys {
+                let mut unit = original.clone();
+                libfreemkv::aacs::content::decrypt_unit(&mut unit, key);
+                if libfreemkv::aacs::content::is_clean(&unit, libfreemkv::disc::ContentFormat::BdTs)
+                {
+                    eprintln!("SUCCESS: Decrypted with entry {}", entry.disc_hash);
+                    // Count TS sync bytes
+                    let ts = (0..32).filter(|&i| unit[4 + i * 192] == 0x47).count();
+                    eprintln!("  TS sync bytes: {}/32", ts);
+                    return;
+                }
             }
         }
 
@@ -1515,7 +1545,7 @@ mod tests {
         let entry = entry.unwrap();
         let vuk = entry.vuk.unwrap();
         let vid = entry.vid.unwrap();
-        let hash_hex = format!("0x{}", entry.disc_hash.trim_start_matches("0x"));
+        let hash_hex = format!("0x{}", libfreemkv::hex::strip_hex_prefix(&entry.disc_hash));
 
         // We need the actual Unit_Key_RO.inf from the disc to compute disc hash.
         // Since we don't have it, we can at least test that the KEYDB lookup

src/lib.rs

@@ -12,7 +12,7 @@
 //! in — then resolve and hand the resulting key to `Disc::decrypt_with`.
 //!
 //! Each source resolves a disc's terminal **Unit Keys** in one shot via
-//! [`KeySource::get_uk`], driving libfreemkv's boil-down crypto primitives for
+//! [`KeySource::get_unit_keys`], driving libfreemkv's boil-down crypto primitives for
 //! whatever level of material it holds. Compose several with [`MultiSource`] in
 //! the caller's chosen order. Reading the encrypted content-sample units a key
 //! server validates on, and applying the resolved keys against a disc, is
@@ -30,7 +30,7 @@ mod paths;
 
 pub use keydb::{KeydbSource, UpdateResult};
 pub use keydb_format::{DiscEntry, KeyDb};
-pub use online::{OnlineSource, validate_keyserver_url};
+pub use online::{MIN_SAMPLE_UNITS, OnlineSource, validate_keyserver_url};
 pub use paths::{default_keydb_path, existing_keydb_path, keydb_search_paths};
 
 // Re-exported for downstream convenience so apps need only depend on this crate
@@ -47,16 +47,15 @@ pub(crate) fn uks_from_vuk(vuk: &[u8; 16], enc_title_keys: &[[u8; 16]]) -> Vec<U
     enc_title_keys
         .iter()
         .enumerate()
-        .map(|(i, e)| UnitKey {
-            idx: i as u32,
-            key: libfreemkv::aacs::derive::decrypt_unit_key(vuk, e),
-        })
+        .map(|(i, e)| UnitKey::new(i as u32, libfreemkv::aacs::derive::decrypt_unit_key(vuk, e)))
         .collect()
 }
 
-/// An ordered composition of key sources, driven as one. [`MultiSource::get_uk`]
-/// tries each inner source in order and returns the first non-empty Unit Key
-/// set. **The caller supplies the list AND the order** — local-first `[Keydb,
+/// An ordered composition of key sources, driven as one.
+/// [`MultiSource::get_unit_keys`] tries each inner source in order and returns
+/// the first non-empty Unit Key set (and [`MultiSource::get_fmts_indexes`] does
+/// the same for the forensic set). **The caller supplies the list AND the
+/// order** — local-first `[Keydb,
 /// Online]`, online-first `[Online, Keydb]`, etc. —
 /// so the "which sources, in what order" policy lives entirely with the
 /// application, not the library. `MultiSource` is itself a [`KeySource`], so it
@@ -73,13 +72,28 @@ impl MultiSource {
 }
 
 impl KeySource for MultiSource {
-    /// Try each inner source in order; the FIRST to return a non-empty Unit Key
-    /// set wins. An inner source that returns empty OR errors is treated as "no
-    /// key here" and the next is tried (a single source failure never blocks the
-    /// chain). All sources exhausted → empty.
-    fn get_uk(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, libfreemkv::Error> {
+    /// Try each inner source in order; the FIRST to return a non-empty base Unit
+    /// Key set wins. An inner source that returns empty OR errors is treated as
+    /// "no key here" and the next is tried (a single source failure never blocks
+    /// the chain). All sources exhausted → empty.
+    fn get_unit_keys(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, libfreemkv::Error> {
         for s in &self.sources {
-            if let Ok(uks) = s.get_uk(ctx) {
+            if let Ok(uks) = s.get_unit_keys(ctx) {
+                if !uks.is_empty() {
+                    return Ok(uks);
+                }
+            }
+        }
+        Ok(Vec::new())
+    }
+
+    /// Forensic-index counterpart: try each inner source's `get_fmts_indexes` in
+    /// the same order and return the first non-empty set. A source with no
+    /// forensic material (the keydb, via the trait default) contributes empty and
+    /// is skipped; on today's discs the online source answers.
+    fn get_fmts_indexes(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, libfreemkv::Error> {
+        for s in &self.sources {
+            if let Ok(uks) = s.get_fmts_indexes(ctx) {
                 if !uks.is_empty() {
                     return Ok(uks);
                 }

src/online.rs

@@ -7,7 +7,7 @@ use std::time::Duration;
 use crate::uks_from_vuk;
 use base64::Engine;
 use libfreemkv::aacs::types::UnitKey;
-use libfreemkv::keysource::ResolveCtx;
+use libfreemkv::keysource::{DecodeSampleSet, ResolveCtx};
 use libfreemkv::{Error, KeySource};
 
 // Upper bound on the MKB forwarded to the key service — kept in lockstep with
@@ -16,6 +16,19 @@ use libfreemkv::{Error, KeySource};
 // record stream is normally a few MiB; this is headroom, not an expected size).
 const MAX_MKB_BYTES: usize = 64 * 1024 * 1024;
 const TIMEOUT_SECS: u64 = 180;
+/// Minimum encrypted-content samples the online source will send in one key
+/// request — re-exported from the base crate ([`libfreemkv::keysource::MIN_SAMPLE_UNITS`])
+/// so this crate and libfreemkv's own FMTS forensic query share ONE value.
+///
+/// The service identifies the key by which of the submitted units it decrypts,
+/// so too few samples — especially on FMTS, where a segment interleaves several
+/// variants at the unit level — can return a key that matches an incidental unit
+/// rather than the one asked about (a false positive). A request carrying fewer
+/// is refused (empty result → the resolver moves to the next source) rather than
+/// sent and trusted. Kept public so callers that GATHER the samples (the CLI,
+/// autorip) sample at least this many — sampling fewer guarantees the request is
+/// skipped and the online source never consulted.
+pub use libfreemkv::keysource::MIN_SAMPLE_UNITS;
 /// Hard cap on the key-service response body. A real unit-key reply is a few
 /// hundred bytes; bound the read so a malicious/compromised server can't drive
 /// the client to OOM with an unbounded body.
@@ -199,7 +212,7 @@ impl OnlineSource {
     /// disc's encrypted title keys from `ctx`). Any failure — no service,
     /// over-cap MKB, network/parse error, or no key for this disc — yields an
     /// empty `Vec` (the resolver tries the next source). `&self`: one-shot is
-    /// the resolver's contract (each source's `get_uk` is called once), so no
+    /// the resolver's contract (each source's `get_unit_keys` is called once), so no
     /// per-call latch is needed.
     fn query(&self, ctx: &dyn ResolveCtx) -> Vec<UnitKey> {
         // No configured service: nothing to resolve.
@@ -219,6 +232,23 @@ impl OnlineSource {
             );
             return Vec::new();
         }
+        // Gather encrypted-content samples and prove the minimum by TYPE: a
+        // `DecodeSampleSet` only exists with >= MIN_SAMPLE_UNITS units, so from here
+        // on the request cannot be built under-sized. The service resolves a key by
+        // which submitted unit it decrypts, so a request carrying too few can return
+        // a key matching an incidental unit (a false positive, seen on FMTS variant
+        // units) — too few → skip this source and fall through to the next.
+        let gathered = ctx.samples(64).unwrap_or_default();
+        let n = gathered.len();
+        let Some(samples) = DecodeSampleSet::new(gathered) else {
+            tracing::info!(
+                target: "freemkv::keysource",
+                samples = n,
+                min = MIN_SAMPLE_UNITS,
+                "too few content samples for a reliable online key request; skipping the online source"
+            );
+            return Vec::new();
+        };
         let b64 = base64::engine::general_purpose::STANDARD;
         let mut body = serde_json::json!({
             // Raw Unit_Key_RO.inf, verbatim — the server does its own parse /
@@ -229,18 +259,15 @@ impl OnlineSource {
         if let Some(vid) = ctx.vid() {
             body["vid_b64"] = serde_json::Value::String(b64.encode(vid.0));
         }
-        // Up to a generous cap of encrypted content samples for server-side
-        // ciphertext validation.
-        if let Ok(samples) = ctx.samples(64) {
-            if !samples.is_empty() {
-                body["units_b64"] = serde_json::Value::Array(
-                    samples
-                        .iter()
-                        .map(|u| serde_json::Value::String(b64.encode(u)))
-                        .collect(),
-                );
-            }
-        }
+        // Encrypted-content samples for server-side ciphertext validation (already
+        // gathered + minimum-checked above).
+        body["units_b64"] = serde_json::Value::Array(
+            samples
+                .units()
+                .iter()
+                .map(|u| serde_json::Value::String(b64.encode(u)))
+                .collect(),
+        );
         // The disc's own title (UDF/ISO volume id), plain text. The key service
         // catalogs it by disc_hash (its disc-titles.json) — independent of keydb.
         if let Some(label) = ctx.title().map(str::trim) {
@@ -303,10 +330,28 @@ impl OnlineSource {
             Ok(j) => j,
             Err(_) => return Vec::new(),
         };
-        // A terminal UK is used directly (CPS unit 0 → committed cps 1, matching
-        // the old `Key::Unit(vec![(1, uk)])`).
-        if let Some(uk) = json.get("UK").and_then(|u| u.as_str()).and_then(parse_uk) {
-            return vec![UnitKey { idx: 0, key: uk }];
+        // `UK` is an ARRAY of hex keys (the service always returns an array now,
+        // even of one). A single element is the base Unit Key. A full set (one per
+        // forensic index, ordered index 1..N) is returned for a forensic sample.
+        // Preserve array order and tag each key with its array position, so the
+        // caller can map position → index (element i = index i+1). A bare string is
+        // still accepted for backward compatibility.
+        if let Some(uk) = json.get("UK") {
+            let mut out = Vec::new();
+            if let Some(s) = uk.as_str() {
+                if let Some(k) = parse_uk(s) {
+                    out.push(UnitKey::new(0, k));
+                }
+            } else if let Some(arr) = uk.as_array() {
+                for (i, v) in arr.iter().enumerate() {
+                    if let Some(k) = v.as_str().and_then(parse_uk) {
+                        out.push(UnitKey::new(i as u32, k));
+                    }
+                }
+            }
+            if !out.is_empty() {
+                return out;
+            }
         }
         // A VUK is derived to the terminal keys locally, via the disc's
         // encrypted title keys from the context — the library owns the crypto.
@@ -320,7 +365,21 @@ impl OnlineSource {
 }
 
 impl KeySource for OnlineSource {
-    fn get_uk(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, Error> {
+    /// Base per-CPS-unit Unit Keys: submit the ctx's content samples and take the
+    /// service's reply (a terminal `UK`, or a `VUK` derived locally). One network
+    /// round-trip; any failure yields empty (the resolver tries the next source).
+    fn get_unit_keys(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, Error> {
+        Ok(self.query(ctx))
+    }
+
+    /// AACS 2.1 forensic index set: the mux injects an index-1 single-phase anchor
+    /// batch as the ctx's samples; the service maps it to the full ordered set of
+    /// forensic index keys, tagged by array position (element `i` → forensic index
+    /// `i + 1`). Same one round-trip as [`get_unit_keys`](Self::get_unit_keys) —
+    /// the difference is purely which samples the mux gathered and how the caller
+    /// reads the reply. The count is whatever the service returns; the mux trusts
+    /// any non-empty result as the complete set and never assumes 32.
+    fn get_fmts_indexes(&self, ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, Error> {
         Ok(self.query(ctx))
     }
 
@@ -416,7 +475,7 @@ mod tests {
     /// it's the deliberate no-op stub.
     #[test]
     fn host_certs_is_noop_empty_no_network() {
-        let src = OnlineSource::new("http://example.invalid/keys", "secret");
+        let src = OnlineSource::new("http://example.test/keys", "secret");
         assert!(
             KeySource::host_certs(&src, None).is_empty(),
             "online host_certs must be an empty no-op (no network)"

tests/key_sources.rs

@@ -1,8 +1,8 @@
 //! Fixture-based integration tests for the published key sources.
 //!
 //! These exercise the *public* surface of `freemkv-keysources` end-to-end —
-//! real files on disk, the real `KeyDb`/`Mapfile` parsers from libfreemkv, and
-//! the `KeySource` trait (`get_uk` over a `ResolveCtx`) the applications drive.
+//! real files on disk, the real `KeyDb` parser from libfreemkv, and
+//! the `KeySource` trait (`get_unit_keys` over a `ResolveCtx`) the applications drive.
 //!
 //! Covered:
 //! - `KeydbSource`: terminal unit-key lookup by disc hash through a real
@@ -71,8 +71,8 @@ fn inputs(hash: &str) -> DiscInputs {
 /// Resolve a source through the public trait over a `DiscInputsCtx`.
 fn resolve(src: &dyn KeySource, inp: &DiscInputs) -> Vec<UnitKey> {
     let ctx = DiscInputsCtx::new(inp);
-    src.get_uk(&ctx)
-        .expect("get_uk must not error for these fixtures")
+    src.get_unit_keys(&ctx)
+        .expect("get_unit_keys must not error for these fixtures")
 }
 
 // ── KeydbSource: real-file lookup by disc hash ──────────────────────────────
@@ -130,7 +130,7 @@ fn keydb_source_missing_file_is_silent_ok_empty() {
     let inp = inputs(DISC_HASH);
     let ctx = DiscInputsCtx::new(&inp);
     assert!(
-        src.get_uk(&ctx)
+        src.get_unit_keys(&ctx)
             .expect("missing keydb is Ok, not Err")
             .is_empty()
     );
@@ -225,7 +225,7 @@ fn online_source_unconfigured_is_silent_no_op() {
 
 #[test]
 fn online_source_metadata() {
-    let src = OnlineSource::new("https://example.invalid/keys", "tok");
+    let src = OnlineSource::new("https://example.test/keys", "tok");
     assert_eq!(src.label(), "online");
     // No host-cert serving today — a no-op empty, no network touched.
     assert!(KeySource::host_certs(&src, None).is_empty());
@@ -258,7 +258,7 @@ impl ScriptedSource {
 }
 
 impl KeySource for ScriptedSource {
-    fn get_uk(&self, _ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, libfreemkv::Error> {
+    fn get_unit_keys(&self, _ctx: &dyn ResolveCtx) -> Result<Vec<UnitKey>, libfreemkv::Error> {
         Ok(self.keys.clone())
     }
     fn label(&self) -> &'static str {
@@ -267,10 +267,7 @@ impl KeySource for ScriptedSource {
 }
 
 fn uk(b: u8) -> UnitKey {
-    UnitKey {
-        idx: 0,
-        key: [b; 16],
-    }
+    UnitKey::new(0, [b; 16])
 }
 
 #[test]