UnfairPlay

UnfairPlay recovers a FairPlay model from an enrolled Mac and uses it to decrypt personalized iOS IPAs. It is a standalone Go program.

It does not log in to Apple, buy apps, or download IPAs. You can use ipatool or another downloader for that part.

Legal and ethical use

Use UnfairPlay only with apps you lawfully acquired and accounts and devices you control. It is intended for interoperability, preservation, and authorized research. The authors do not condone piracy, credential theft, copyright infringement, or unauthorized distribution of decrypted apps.

Discord

Project discussion and support: UnfairPlay Discord.

Build

go build -o unfairplay ./cmd/unfairplay

Usage

First, sign in to the native Mac App Store. Install an iPhone or iPad app and open it once. Download a matching encrypted IPA with the same Apple Account.

Set up reusable decryption once:

sudo ./unfairplay setup \
  --app /Applications/App.app \
  --ipa App.ipa

Large enrollment databases print bounded recovery progress to standard error. The final JSON result remains on standard output.

The saved model is private. It is tied to the Mac App Store enrollment, not to one app, so it can decrypt other personalized IPAs from the same enrollment. Back it up only in encrypted storage and never share it.

Decrypt another IPA:

./unfairplay decrypt --input AnotherApp.ipa

The default model directory is inside the user configuration directory. Set UNFAIRPLAY_MODEL_DIR or pass --model to use another location.

IPAs with extensions and watch apps are decrypted in one pass.

The output keeps the input's SC_Info licenses and iTunesMetadata.plist, which identify the Store account. To create a redacted copy for private analysis or authorized collaboration, add --strip-account-data: it omits every SC_Info member and removes the Apple ID and purchaser fields from iTunesMetadata.plist. Redaction does not authorize redistributing the app; the legal and ethical use terms above still apply. Test without keeping plaintext with:

./unfairplay verify --input AnotherApp.ipa

The decryption path handles ARMv7, ARM64, and ARM64_32/watchOS slices. ARMv6/Thumb-1 parsing is experimental and those binaries are not supported. Available pre-encryption page hashes must match; a mismatch fails closed. Older executables without these tables can decrypt, but report plaintext_verified=false.

Convert an IPA for macOS

This requires an encrypted IPA personalized for the same Store enrollment as your saved model. Convert it with:

./unfairplay convert-ipa-macos \
  --input App.ipa \
  --model /private/path/fairplay-enrollment.bin

Omit --model to use the saved model. The default output is App.macos.ipa. Use --output to choose another path or --force to replace an existing output.

The command uses a saved version-2 enrollment model. You can instead use a matching private 16-byte credential:

chmod 600 credential.bin
./unfairplay convert-ipa-macos \
  --input App.ipa \
  --credential credential.bin

The conversion:

• decodes the current private record with the direct enrollment model;
• validates and rewrites the personalized SINF into the macOS layout;
• preserves its app key, signature, rights, and other private fields;
• adds every SINF copy declared by Apple for encrypted frameworks and

• leaves all Mach-O executables byte-identical and encrypted.

The result is still an IPA, not a macOS installer. A macOS iOS-app wrapper or compatible installer must preserve this basic layout:

App iOS.app/
  WrappedBundle -> Wrapper/App.app
  Wrapper/App.app
  Wrapper/iTunesMetadata.plist

The converted IPA and wrapper contain a private account license. Keep them private. This feature does not decrypt, modify, re-sign, or bypass checks inside the app. Apps may still reject macOS, require unavailable hardware, or depend on services that are not present on macOS.

Advanced commands

collect and recover expose the two setup stages for diagnostics and archived captures. doctor checks a capture, IPA, or model.

sudo ./unfairplay collect --app /Applications/App.app --ipa App.ipa --output App.capture
./unfairplay recover --capture App.capture --output App.recovery

FAQ

What is an enrollment?

An enrollment is the FairPlay state created when an Apple Account uses the Mac App Store on a Mac. It links the account, Mac, and FairPlay selector. setup turns that state into a reusable private model.

What are SINF, SUPF, SIDB, and SC Info?

• Personalized SINF: an app license created for one Store enrollment. It

• SUPF/SUPP: signed per-executable records used to derive keys and IVs for

• SC_Info: the directory inside an installed app or IPA that contains its

• System SC Info: the private Mac FairPlay state directory. Its SIDB and

These files are private. Do not publish or share them.

Do I need to run setup for every app?

No. One model can decrypt different IPAs personalized for the same enrollment. Each app still has its own key inside its personalized SINF.

Why might another macOS build fail?

Apple can change enrollment state layouts or semantic tables. UnfairPlay follows explicit SIDB version, state-slot, root-cursor, and selector rules. An unmapped format or tag-constructor path stops recovery with an error. It never publishes a model until the matching IPA decrypts and passes the applicable validation checks; missing plaintext hashes remain explicitly unverified.

Patches and test reports are welcome. Include the macOS build, UnfairPlay commit, and a redacted error. Keep app identities, identifying IPA measurements and private paths out of public reports. Never share SIDB, SINF, hardware identity, enrollment models, decrypted apps, or Apple credentials.

Can decryption run on another operating system?

Yes. Collection must start on an enrolled Mac. You can either run setup on that Mac and securely copy the resulting model, or copy a complete private collect bundle and run recover elsewhere. The bundle contains the installed license files, system SC Info state, built-in IOMACAddress, matching IPA, and macOS build metadata.

The recovered model and personalized IPAs can then be used on macOS or Linux; the native fairplayd daemon is never launched by this tool. Windows builds compile, but Windows decryption is not enabled until equivalent private-file permission checks are implemented.

Support

Recovery follows the mapped current-container and tree format. It derives one state slot, a hardware-dependent root cursor and tag codebook, then selects the SINF's exact user/key path and authenticates its single value. It does not try other records or windows when that value fails authentication. Only the mapped tree format is supported.

The hardware tag constructor uses a byte mixer followed by AES-CBC and an affine map of each output word. Selection-state derivation processes the selected prefix with AES-CBC and a final AES key transform. All constants are part of the mapped algorithm. Production loads no native executable or constructor profile. Support is determined by format and authenticated route; unknown versions, tags and selected-route geometry fail closed. SINF authentication, complete IPA processing, and every applicable validation check remain mandatory. Older IPAs without pre-encryption hashes remain explicitly unverified rather than being reported as verified.

IPA decryption uses explicit SC_Info/Manifest.plist SINF replication paths, or the executable's adjacent SINF when no mapping is declared. Paired legacy and v5 SUPFs must have identical architecture and page records; a legacy SUPF's signature-blob hash must match its executable. Conflicts within the selected page-key class fail closed. Recovery uses one canonical set of runtime inputs without a broader license retry. Thin Mach-O images can also use signed .supp/.v4.supp page tables, indexed from file offset zero. The encrypted page records are selected by the declared encryption range, and legacy signature-blob bindings are checked. SUPP-only fat images are unsupported. Architecture-indexed SUPF files take precedence when present; a malformed selected class never triggers a retry with the other class. SINF manifests must declare exactly one source; existing replicas must match that source. Multi-source manifests are unsupported.

Plaintext validation checks every CodeDirectory pre-encryption hash slot that intersects an encrypted range. Instruction scoring and sampled-page checks are not used. Every available pre-encryption table is checked. Older directories or a zero pre-encryption offset mean no table; a malformed nonzero table fails closed.

Images with no table report validation as unavailable, and the overall plaintext_verified flag is false if any image lacks coverage. These checks establish consistency with the embedded hashes, not Apple CMS signature trust. Unencrypted pages outside those ranges are not covered by this plaintext check. Decryption reports use unfairplay-decryption-v2; consumers of the removed instruction-audit fields must migrate to the plaintext validation fields.

macOS arm64 and Linux amd64/arm64 are supported. Windows is compile-tested but cannot yet enforce the required private-file permissions.

During setup, the installed app, matching IPA, Mac state, and hardware identity must belong to the same enrollment. The resulting model can then decrypt other IPAs personalized for that enrollment. Account or selector mismatches are rejected.

Keep capture and model files private. Do not share SIDB, SINF, hardware data, recovery models, or decrypted apps. Decrypted IPAs are analysis files and need signing before installation.

Reporting problems

Private controls do not establish support for every layout or independent enrollment. Do not infer support from the macOS build alone. Build it from source and run setup normally. Confirm the binary with ./unfairplay --version. Reports should include only that version output, the macOS build and a redacted error. Keep app identities, IPA measurements, account/hardware identifiers and private paths out of public reports. Never attach SIDB, SINF, hardware identity, models, credentials, or decrypted IPAs to a public issue.

Releases

Run the private control matrix in QA.md before tagging a release.

Tags matching v* publish binaries and SHA256SUMS through GitHub Actions. Tags such as v0.2.0-rc.1 create prereleases.

License

MIT. Third-party notices are in NOTICE, LICENSE-DARKPHOENIX.txt, and LICENSE-MACOSFAIRFREE.txt.