dpapi-forensic

Parse and decrypt Windows DPAPI from raw bytes — DPAPI_BLOB, AES/3DES blob decryption given a master key, and Chrome/Edge v10/v20 cookie unwrap — with audited crypto and zero I/O.

DPAPI is one of the largest Windows credential-protection surfaces: Chrome/Edge saved passwords and the cookie key, Credential Manager, Vault, Wi-Fi keys, and the master-key files themselves. The blob format and the decrypt-given-key crypto are identical on disk and in live memory — so dpapi-core is a pure &[u8]-in library that both a memory tool and a disk tool can share.

Quick start

[dependencies]
dpapi-core = "0.1"

use dpapi_core::{parse_dpapi_blob, decrypt_dpapi_blob};

// `master_key` comes from your key source (LSASS cache in memory, or a
// master-key file + password derivation on disk).
let blob = parse_dpapi_blob(raw_blob_bytes)?;
let plaintext = decrypt_dpapi_blob(&blob, master_key)?;
# Ok::<(), dpapi_core::DpapiError>(())

Chrome/Edge cookies (Local State key already recovered):

use dpapi_core::{detect_chrome_cookie_encoding, decrypt_v10_cookie, ChromeCookieEncoding};

if let ChromeCookieEncoding::V10 { nonce, ciphertext } =
    detect_chrome_cookie_encoding(encrypted_value)
{
    let cookie = decrypt_v10_cookie(&nonce, &ciphertext, &aes_key)?;
}
# Ok::<(), dpapi_core::DpapiError>(())

What it does

dpapi-core (the library) is byte-oriented and performs no I/O:

• parse_dpapi_blob(&[u8]) — decode the DPAPI_BLOB wire format: version, master-key GUID, description, algorithm IDs, HMAC key, ciphertext, and HMAC.
• decrypt_dpapi_blob(blob, master_key) — derive the session key (HMAC-SHA1) and decrypt with AES-256-CBC or 3DES-CBC.
• detect_chrome_cookie_encoding / decrypt_v10_cookie — classify a Chrome/Edge encrypted_value (v10/v20/classic-DPAPI/raw) and unwrap the AES-256-GCM variants.

All cryptography uses audited RustCrypto crates (aes, aes-gcm, cbc, des, hmac, sha1, sha2). No primitive is hand-rolled. A bad key, IV length, or HMAC surfaces as a typed DpapiError — the library never fabricates plausible-but-wrong plaintext.

Status

Step 1 (this release) ships the byte-oriented dpapi-core primitives, validated by the unit tests carried over from memory-forensic. The dpapi-forensic crate is a stub that re-exports dpapi-core and documents the roadmap.

Step 2 (planned):

• masterkey.rs in dpapi-core — parse master-key files (%APPDATA%\Microsoft\Protect\<SID>\<GUID>) and derive the key-protection key from the user password (SHA1 → PBKDF2-HMAC) or the domain backup key.
• dpapi-forensic auditor — enumerate and decrypt Chrome/Edge passwords + cookie key, Credential Manager, Vault, and Wi-Fi keys on an acquired filesystem, emitting graded forensicnomicon findings.
• dpapi4n6 CLI per the fleet *4n6 pattern, plus a tag-driven release workflow.

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