secure-enclave-rs

Safe Rust bindings to Apple's Secure Enclave, built on the macOS Security framework. Created because nothing else in the Rust ecosystem wraps the Secure Enclave APIs without leaking unsafe CoreFoundation pointers or pulling in the entire security-framework crate.

Python bindings live alongside in py_secure_enclave/.

Features

Use hardware-backed P-256 keys in the Secure Enclave, with:

• Key generation with arbitrary SecAccessControl policies (biometry, device passcode, application password, combinations)
• Persistence in the keychain by application tag
• ECDSA-SHA256 signing and verification
• ECIES encryption / decryption (X9.63 KDF + AES-GCM)
• ECDH key agreement with X9.63 KDF
• Optional ES256 JWT signing (RFC 7519 / RFC 7523) under the jwt feature
• Public-key export as X9.62 uncompressed bytes; reconstruction from bytes for server-side verification

Private keys never leaves Apple's Secure Enclave.

Requirements

Just macOS with Secure Enclave:

• Apple Silicon or
• Intel with a T2 chip or later

Installation

[dependencies]
secure-enclave-rs = "1"

# For JWT / ES256 support:
secure-enclave-rs = { version = "1", features = ["jwt"] }

Quick example

use secure_enclave_rs::{SecAccessControlFlags, SecureEnclaveKey, SecureEnclaveKeyOptions};

let key = SecureEnclaveKey::generate(&SecureEnclaveKeyOptions {
    tag: b"com.example.signing-key",
    access_flags: SecAccessControlFlags::BIOMETRY_ANY,
    permanent: true,
})?;

let sig = key.sign(b"hello world")?;         // prompts Face ID / Touch ID
assert!(key.verify(b"hello world", &sig)?);

let peer_pub = &[0x04u8; 65]; // peer's X9.62 uncompressed public key
let shared = secure_enclave_rs::derive_shared_secret(&key, peer_pub, 32, &[])?;

Full end-to-end examples in examples/:

File	Demonstrates
key_exists.rs	Generate, persist, retrieve, remove
encryption.rs	ECIES encrypt / decrypt
key_exchange.rs	ECDH shared secret derivation
biometric_auth.rs	BIOMETRY_ANY + DEVICE_PASSCODE flags
attestation.rs	Server-verified challenge / response
dek_wrapping.rs	Wrapping a symmetric DEK with an SE key
jwt_assertion.rs	ES256 JWT (requires --features jwt)

Run one with cargo run --example encryption.

Code signing and entitlements

Only code-signed processes can use Apple's Secure Enclave. However, different operations have different entitlement requirements. None of the methods in this library work in an unsigned binary on a Mac with System Integrity Protection (SIP) enabled.

Ephemeral keys (permanent: false)

If you don't intend to store keys permanently in the Secure Enclave, you only need the process to be code-signed. An ad-hoc signature is enough (codesign -s - target/debug/my-binary). Apple Development certificates also work. No provisioning profile, no special entitlements.

Everything except keychain persistence works here — sign, verify, encrypt, decrypt, ECDH, JWT signing.

Persistent keys (permanent: true)

Calls into SecItemAdd / SecItemCopyMatching require the binary to present a keychain access group. As such, you'll need these three things too:

1. An Apple Development code-signing identity (not ad-hoc).

2. A keychain-access-groups entitlement at sign time, e.g.

   <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
     "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
   <plist version="1.0"><dict>
     <key>com.apple.application-identifier</key>
     <string>TEAMID.com.example.myapp</string>
     <key>com.apple.developer.team-identifier</key>
     <string>TEAMID</string>
     <key>keychain-access-groups</key>
     <array><string>TEAMID.com.example.myapp</string></array>
   </dict></plist>

3. A matching macOS provisioning profile embedded in the .app as Contents/embedded.provisionprofile. Because keychain-access-groups is a restricted entitlement, AMFI kills the process at launch without one (Code Signing Error: No matching profile found).

   Any Apple ID, including a free Personal Team, can issue a Development profile from Xcode. No paid Developer Program required. See the py_secure_enclave README for step-by-step instructions; the resulting .provisionprofile works for both Rust and Python consumers.

Without a profile, SecureEnclaveKey::generate(..., permanent: true) and get / remove_by_tag all return Error::Os(-34018) (errSecMissingEntitlement).

Biometric / passcode access flags

No additional entitlements beyond the above. MacOS handles displaying a popup prompt and the Secure Enclave handles the evaluation.

Thread safety

SecureEnclaveKey is deliberately not Send/Sync as Apple's documentation is ambiguous about concurrency guarantees on macOS Security-framework objects, so the type is pinned to its creating thread.

License

Copyright © 2026, Carl Ian Voller. Released under the BSD-3-Clause License.