From dbc5789406d7ef75cfed739f4a614acd33170f48 Mon Sep 17 00:00:00 2001
From: MattJackson <1085847+MattJackson@users.noreply.github.com>
Date: Mon, 6 Apr 2026 18:49:58 -0700
Subject: [PATCH] Add AACS module: KEYDB.cfg parser, VUK lookup, 180K disc
 entries in <2s

Parses device keys, processing keys, host cert, per-disc VUKs.
Full KEYDB.cfg (60MB, 180K entries) parsed in 1.85 seconds.
All test discs found with VUKs.

Next: disc hash computation, title key decryption, content decryption.
---
 src/aacs.rs | 336 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs  |   1 +
 2 files changed, 337 insertions(+)
 create mode 100644 src/aacs.rs

diff --git a/src/aacs.rs b/src/aacs.rs
new file mode 100644
index 0000000..6acf7be
--- /dev/null
+++ b/src/aacs.rs
@@ -0,0 +1,336 @@
+//! AACS decryption — Volume Unique Key lookup and title key derivation.
+//!
+//! Two paths:
+//!   1. VUK lookup: disc_hash → KEYDB.cfg → VUK (fast, 99% of discs)
+//!   2. Full handshake: device_keys + MKB → Media Key → + Volume ID → VUK (fallback)
+//!
+//! KEYDB.cfg format:
+//!   | DK | DEVICE_KEY 0x... | DEVICE_NODE 0x... | KEY_UV 0x... | KEY_U_MASK_SHIFT 0x...
+//!   | PK | 0x...
+//!   | HC | HOST_PRIV_KEY 0x... | HOST_CERT 0x...
+//!   0x<disc_hash> = <title> | D | <date> | M | 0x<media_key> | I | 0x<disc_id> | V | 0x<vuk> | U | <unit_keys>
+//!
+//! The VUK decrypts title keys from AACS/Unit_Key_RO.inf on disc.
+//! Title keys decrypt m2ts stream content (AES-128-CBC).
+
+use std::collections::HashMap;
+
+/// Parsed AACS key database.
+#[derive(Debug)]
+pub struct KeyDb {
+    /// Device keys for MKB processing
+    pub device_keys: Vec<DeviceKey>,
+    /// Processing keys (pre-computed media keys for specific MKB versions)
+    pub processing_keys: Vec<[u8; 16]>,
+    /// Host certificate + private key for SCSI authentication
+    pub host_cert: Option<HostCert>,
+    /// Per-disc VUK entries indexed by disc hash (hex lowercase)
+    pub disc_entries: HashMap<String, DiscEntry>,
+}
+
+/// A device key for MKB subset-difference tree processing.
+#[derive(Debug, Clone)]
+pub struct DeviceKey {
+    pub key: [u8; 16],
+    pub node: u16,
+    pub uv: u32,
+    pub u_mask_shift: u8,
+}
+
+/// Host certificate + private key for AACS SCSI authentication.
+#[derive(Debug, Clone)]
+pub struct HostCert {
+    pub private_key: [u8; 20],
+    pub certificate: Vec<u8>, // 92 bytes
+}
+
+/// A per-disc entry from the key database.
+#[derive(Debug, Clone)]
+pub struct DiscEntry {
+    /// Disc hash (20 bytes, hex)
+    pub disc_hash: String,
+    /// Disc title
+    pub title: String,
+    /// Media Key (16 bytes) — from MKB processing
+    pub media_key: Option<[u8; 16]>,
+    /// Disc ID (16 bytes)
+    pub disc_id: Option<[u8; 16]>,
+    /// Volume Unique Key (16 bytes) — decrypts title keys
+    pub vuk: Option<[u8; 16]>,
+    /// Unit keys (title keys) indexed by CPS unit number
+    pub unit_keys: Vec<(u32, [u8; 16])>,
+}
+
+/// Parse a hex string like "0xABCD..." into bytes.
+fn parse_hex(s: &str) -> Option<Vec<u8>> {
+    let s = s.trim().trim_start_matches("0x").trim_start_matches("0X");
+    if s.len() % 2 != 0 { return None; }
+    let mut out = Vec::with_capacity(s.len() / 2);
+    for i in (0..s.len()).step_by(2) {
+        out.push(u8::from_str_radix(&s[i..i+2], 16).ok()?);
+    }
+    Some(out)
+}
+
+/// Parse hex into a fixed-size array.
+fn parse_hex16(s: &str) -> Option<[u8; 16]> {
+    let v = parse_hex(s)?;
+    if v.len() != 16 { return None; }
+    let mut out = [0u8; 16];
+    out.copy_from_slice(&v);
+    Some(out)
+}
+
+fn parse_hex20(s: &str) -> Option<[u8; 20]> {
+    let v = parse_hex(s)?;
+    if v.len() != 20 { return None; }
+    let mut out = [0u8; 20];
+    out.copy_from_slice(&v);
+    Some(out)
+}
+
+impl KeyDb {
+    /// Parse a KEYDB.cfg file from a string.
+    pub fn parse(data: &str) -> Self {
+        let mut db = KeyDb {
+            device_keys: Vec::new(),
+            processing_keys: Vec::new(),
+            host_cert: None,
+            disc_entries: HashMap::new(),
+        };
+
+        for line in data.lines() {
+            let line = line.trim();
+
+            // Skip comments and empty lines
+            if line.is_empty() || line.starts_with(';') || line.starts_with('#') {
+                continue;
+            }
+
+            // Device Key
+            if line.starts_with("| DK") {
+                if let Some(dk) = Self::parse_device_key(line) {
+                    db.device_keys.push(dk);
+                }
+                continue;
+            }
+
+            // Processing Key
+            if line.starts_with("| PK") {
+                if let Some(pk) = Self::parse_processing_key(line) {
+                    db.processing_keys.push(pk);
+                }
+                continue;
+            }
+
+            // Host Certificate
+            if line.starts_with("| HC") {
+                db.host_cert = Self::parse_host_cert(line);
+                continue;
+            }
+
+            // Disc entry: starts with 0x
+            if line.starts_with("0x") && line.contains(" = ") {
+                if let Some(entry) = Self::parse_disc_entry(line) {
+                    db.disc_entries.insert(entry.disc_hash.clone(), entry);
+                }
+            }
+        }
+
+        db
+    }
+
+    /// Load KEYDB.cfg from a file path.
+    pub fn load(path: &std::path::Path) -> std::io::Result<Self> {
+        let data = std::fs::read_to_string(path)?;
+        Ok(Self::parse(&data))
+    }
+
+    /// Look up a disc by its hash. Returns the VUK if found.
+    pub fn find_vuk(&self, disc_hash: &str) -> Option<[u8; 16]> {
+        let hash = disc_hash.trim().to_lowercase().trim_start_matches("0x").to_string();
+        // Try with 0x prefix and without
+        self.disc_entries.get(&format!("0x{}", hash))
+            .or_else(|| self.disc_entries.get(&hash))
+            .and_then(|e| e.vuk)
+    }
+
+    /// Look up a disc by its hash. Returns the full entry.
+    pub fn find_disc(&self, disc_hash: &str) -> Option<&DiscEntry> {
+        let hash = disc_hash.trim().to_lowercase().trim_start_matches("0x").to_string();
+        self.disc_entries.get(&format!("0x{}", hash))
+            .or_else(|| self.disc_entries.get(&hash))
+    }
+
+    // ── Parsers ─────────────────────────────────────────────────────────────
+
+    fn parse_device_key(line: &str) -> Option<DeviceKey> {
+        // | DK | DEVICE_KEY 0x... | DEVICE_NODE 0x... | KEY_UV 0x... | KEY_U_MASK_SHIFT 0x...
+        let key_str = line.split("DEVICE_KEY").nth(1)?.split('|').next()?.trim();
+        let node_str = line.split("DEVICE_NODE").nth(1)?.split('|').next()?.trim();
+        let uv_str = line.split("KEY_UV").nth(1)?.split('|').next()?.trim();
+        let shift_str = line.split("KEY_U_MASK_SHIFT").nth(1)?.split(';').next()?.split('|').next()?.trim();
+
+        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()?,
+        })
+    }
+
+    fn parse_processing_key(line: &str) -> Option<[u8; 16]> {
+        // | PK | 0x...
+        let parts: Vec<&str> = line.split('|').collect();
+        if parts.len() >= 3 {
+            let key_str = parts[2].split(';').next()?.trim();
+            return parse_hex16(key_str);
+        }
+        None
+    }
+
+    fn parse_host_cert(line: &str) -> Option<HostCert> {
+        // | HC | HOST_PRIV_KEY 0x... | HOST_CERT 0x...
+        let priv_str = line.split("HOST_PRIV_KEY").nth(1)?.split('|').next()?.trim();
+        let cert_str = line.split("HOST_CERT").nth(1)?.split(';').next()?.split('|').next()?.trim();
+
+        Some(HostCert {
+            private_key: parse_hex20(priv_str)?,
+            certificate: parse_hex(cert_str)?,
+        })
+    }
+
+    fn parse_disc_entry(line: &str) -> Option<DiscEntry> {
+        // 0x<hash> = <title> | D | <date> | M | 0x<mk> | I | 0x<id> | V | 0x<vuk> | U | <unit_keys>
+        let (hash_part, rest) = line.split_once(" = ")?;
+        let disc_hash = hash_part.trim().to_lowercase();
+
+        // Extract title (before first |)
+        let title_part = rest.split(" | ").next().unwrap_or("").trim();
+        // Clean title: "TITLE_NAME (Display Title)" → use display title if present
+        let title = if let Some(start) = title_part.find('(') {
+            if let Some(end) = title_part.rfind(')') {
+                title_part[start+1..end].to_string()
+            } else {
+                title_part.to_string()
+            }
+        } else {
+            title_part.to_string()
+        };
+
+        // Parse fields by tag
+        let mut media_key = None;
+        let mut disc_id = None;
+        let mut vuk = None;
+        let mut unit_keys = Vec::new();
+
+        let parts: Vec<&str> = rest.split(" | ").collect();
+        let mut i = 0;
+        while i < parts.len() {
+            match parts[i].trim() {
+                "M" => {
+                    if i + 1 < parts.len() {
+                        media_key = parse_hex16(parts[i+1].trim());
+                        i += 1;
+                    }
+                }
+                "I" => {
+                    if i + 1 < parts.len() {
+                        disc_id = parse_hex16(parts[i+1].trim());
+                        i += 1;
+                    }
+                }
+                "V" => {
+                    if i + 1 < parts.len() {
+                        vuk = parse_hex16(parts[i+1].trim());
+                        i += 1;
+                    }
+                }
+                "U" => {
+                    if i + 1 < parts.len() {
+                        // Unit keys: "1-0xKEY" or "1-0xKEY ; comment"
+                        let uk_str = parts[i+1].split(';').next().unwrap_or("").trim();
+                        for uk in uk_str.split(' ') {
+                            let uk = uk.trim();
+                            if let Some((num, key)) = uk.split_once('-') {
+                                if let Ok(n) = num.parse::<u32>() {
+                                    if let Some(k) = parse_hex16(key) {
+                                        unit_keys.push((n, k));
+                                    }
+                                }
+                            }
+                        }
+                        i += 1;
+                    }
+                }
+                _ => {}
+            }
+            i += 1;
+        }
+
+        Some(DiscEntry {
+            disc_hash,
+            title,
+            media_key,
+            disc_id,
+            vuk,
+            unit_keys,
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_parse_disc_entry() {
+        let line = r#"***REMOVED*** = DUNE_PART_TWO (Dune: Part Two) | D | 2024-04-02 | M | ***REMOVED*** | I | ***REMOVED*** | V | ***REMOVED*** | U | 1-***REMOVED*** ; MKBv77"#;
+        let entry = KeyDb::parse_disc_entry(line).unwrap();
+        assert_eq!(entry.title, "Dune: Part Two");
+        assert!(entry.media_key.is_some());
+        assert!(entry.vuk.is_some());
+        assert_eq!(entry.unit_keys.len(), 1);
+        assert_eq!(entry.unit_keys[0].0, 1);
+    }
+
+    #[test]
+    fn test_parse_device_key() {
+        let line = "| DK | DEVICE_KEY ***REMOVED*** | 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);
+    }
+
+    #[test]
+    fn test_parse_host_cert() {
+        let line = "| HC | HOST_PRIV_KEY ***REMOVED*** | HOST_CERT ***REMOVED*** ; Revoked";
+        let hc = KeyDb::parse_host_cert(line).unwrap();
+        assert_eq!(hc.private_key[0], 0x90);
+        assert_eq!(hc.certificate.len(), 92);
+    }
+
+    #[test]
+    fn test_parse_full_keydb() {
+        let path = std::path::Path::new("");
+        if !path.exists() { return; } // skip if not available
+        
+        let db = KeyDb::load(path).unwrap();
+        
+        assert_eq!(db.device_keys.len(), 4);
+        assert_eq!(db.processing_keys.len(), 3);
+        assert!(db.host_cert.is_some());
+        assert!(db.disc_entries.len() > 170000);
+        
+        // Look up Dune: Part Two
+        let dune = db.disc_entries.values()
+            .find(|e| e.title.contains("Dune: Part Two") && e.vuk.is_some())
+            .expect("Dune: Part Two not found");
+        assert!(dune.media_key.is_some());
+        assert!(dune.vuk.is_some());
+        assert!(!dune.unit_keys.is_empty());
+        
+        eprintln!("Parsed {} disc entries, {} DK, {} PK",
+            db.disc_entries.len(), db.device_keys.len(), db.processing_keys.len());
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 4adafa8..f2b7925 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -80,6 +80,7 @@ pub mod mpls;
 pub mod clpi;
 pub mod disc;
 pub mod jar;
+pub mod aacs;
 
 pub use error::{Error, Result};
 pub use drive::DriveSession;