evolve-pak

Command-line tool for inspecting, extracting, auditing, and repacking Evolve .pak (.m2k) archives.

Pak format

Evolve pak files are ZIP archives where all entry data is encrypted with Twofish in CTR mode (little-endian 128-bit counter). Each file uses a unique key and IV stored in the ZIP End-of-Central-Directory comment as 16 RSA-1024 PKCS#1 OAEP-SHA256 encrypted blocks. The vanilla game ships with an embedded RSA-1024 public key; the revival project generates its own keypair to sign custom pak files.

The ZIP local file header is itself the first four encrypted bytes of the stream — there is no plaintext magic at byte 0. File data resets the CTR counter to the IV (it does not continue from the header stream).

Commands

evolve-pak list <file.pak>
    List all entries with compressed size, uncompressed size, and path.

evolve-pak extract <file.pak> [outdir]
    Extract all entries. Defaults to a directory named after the pak file.

evolve-pak inspect <file.pak>
    Show pak header info (magic variant, file size).

evolve-pak audit <game-dir>
    Size breakdown across all pak files in a game directory.
      --contents, -c    Break down by file category inside each pak.

evolve-pak perf <game-dir>
    List the largest entries across all openable pak files.
      --top, -n N       Number of entries to show (default 20).

evolve-pak keygen
    Generate an RSA-1024 keypair (revival.priv, revival.pub).
      --out-dir <dir>   Output directory (default: current directory).
      --force           Overwrite existing key files.

evolve-pak pack <dir> <out.pak>
    Pack a directory into an encrypted pak file.
      --privkey <path>  Path to revival.priv (required).

evolve-pak rekey <game-dir>
    Validate or re-sign all pak EOCD comments with the revival key.
      --privkey <path>  Path to revival.priv (required with --in-place).
      --in-place        Write new EOCD comments back to the pak files.

evolve-pak keyfind <Evolve.exe> <any.pak>
    Scan Evolve.exe for the Twofish key that decrypts a given pak file.

Build

Requires Go 1.21+.

go build -o evolve-pak ./cmd

Examples

List a pak:

evolve-pak list Scripts.pak

Extract to a directory:

evolve-pak extract Scripts.pak ./out

Generate a revival keypair and rekey all game pak files:

evolve-pak keygen --out-dir ./keys
evolve-pak rekey /path/to/Evolve --privkey ./keys/revival.priv --in-place

Create a custom pak from a directory:

evolve-pak pack ./my-scripts custom.pak --privkey ./keys/revival.priv

After rekeying, place revival.pub and the dbghelp.dll injector in bin64_SteamRetail/ so the game can verify the new signatures at load time.

Related

• injector — dbghelp proxy that patches the vanilla RSA key in game memory at load time