Library and CLI tool for working with Unreal Engine .pak files.
- Supports reading and writing a wide range of versions
- Easy to use API while providing low level control:
- Only parses index initially and reads file data upon request
- Can rewrite index in place to perform append or delete operations without rewriting entire pak
repak CLI
- Sane handling of mount points: defaults to
../../../but can be configured via flag - 2x faster unpacking over
UnrealPak - Unpacking is guarded against malicious pak that attempt to write to parent directories
$ repak --help Usage: repak [OPTIONS] <COMMAND> Commands: info Print .pak info list List .pak files hash-list List .pak files and the SHA256 of their contents. Useful for finding differences between paks unpack Unpack .pak file pack Pack directory into .pak file get Reads a single file to stdout help Print this message or the help of the given subcommand(s) Options: -a, --aes-key <AES_KEY> 256 bit AES encryption key as base64 or hex string if the pak is encrypted -h, --help Print help -V, --version Print version$ find mod mod mod/assets mod/assets/AssetA.uasset mod/assets/AssetA.uexp $ repak pack -v mod packing assets/AssetA.uasset packing assets/AssetA.uexp Packed 4 files to mod.pak $ repak list mod.pak assets/AssetA.uasset assets/AssetA.uexp$ repak --aes-key 0x12345678 unpack MyEncryptedGame.pak Unpacked 12345 files to MyEncryptedGame from MyEncryptedGame.pak| UE Version | Version | Version Feature | Read | Write |
|---|---|---|---|---|
| 1 | Initial | ❔ | ❔ | |
| 4.0-4.2 | 2 | NoTimestamps | ✔️ | ✔️ |
| 4.3-4.15 | 3 | CompressionEncryption | ✔️ | ✔️ |
| 4.16-4.19 | 4 | IndexEncryption | ✔️ | ✔️ |
| 4.20 | 5 | RelativeChunkOffsets | ✔️ | ✔️ |
| 6 | DeleteRecords | ❔ | ❔ | |
| 4.21 | 7 | EncryptionKeyGuid | ✔️ | ✔️ |
| 4.22 | 8A | FNameBasedCompression | ✔️ | ✔️ |
| 4.23-4.24 | 8B | FNameBasedCompression | ✔️ | ✔️ |
| 4.25 | 9 | FrozenIndex | ✔️ | ✔️1 |
| 10 | PathHashIndex | ❔ | ❔ | |
| 4.26-5.32 | 11 | Fnv64BugFix | ✔️ | ✔️ |
| Feature | Read | Write |
|---|---|---|
| Compression | ✔️ | 〰️3 |
| Encrypted Index | ✔️ | ❌ |
| Encrypted Data | ✔️ | ❌ |
Supports reading encrypted (both index and/or data) and compressed paks. Writing does not support compression or encryption yet.
As far as I can tell, the index is not necessarily written deterministically by UnrealPak. repak uses BTreeMap in place of HashMap to deterministically write the index and happens to rewrite the test paks in the same order, but this more likely than not stops happening on larger pak files.
UnrealPak includes a directory entry in the full directory index for all parent directories back to the pak root for a given file path regardless of whether those directories contain any files or just other directories. repak only includes directories that contain files. So far no functional differences have been observed as a result.
- unpak: original crate featuring read-only pak operations
- rust-u4pak's README detailing the pak file layout
- jieyouxu for serialization implementation of the significantly more complex V11 index
