from: github.com/remko/age-plugin-se

Sources/Crypto.swift

@@ -0,0 +1,78 @@
+import Foundation
+
+#if !os(Linux) && !os(Windows)
+  import CryptoKit
+  import LocalAuthentication
+#else
+  import Crypto
+  struct SecAccessControl {}
+#endif
+
+/// Abstraction for random/unpredictable/system-specific crypto operations
+protocol Crypto {
+  var isSecureEnclaveAvailable: Bool { get }
+
+  func newSecureEnclavePrivateKey(dataRepresentation: Data) throws -> SecureEnclavePrivateKey
+  func newSecureEnclavePrivateKey(accessControl: SecAccessControl) throws -> SecureEnclavePrivateKey
+  func newEphemeralPrivateKey() -> P256.KeyAgreement.PrivateKey
+}
+
+protocol SecureEnclavePrivateKey {
+  var publicKey: P256.KeyAgreement.PublicKey { get }
+  var dataRepresentation: Data { get }
+
+  func sharedSecretFromKeyAgreement(with publicKeyShare: P256.KeyAgreement.PublicKey) throws
+    -> SharedSecret
+}
+
+#if !os(Linux) && !os(Windows)
+  class CryptoKitCrypto: Crypto {
+    let context = LAContext()
+
+    var isSecureEnclaveAvailable: Bool {
+      return SecureEnclave.isAvailable
+    }
+
+    func newSecureEnclavePrivateKey(dataRepresentation: Data) throws -> SecureEnclavePrivateKey {
+      return try SecureEnclave.P256.KeyAgreement.PrivateKey(
+        dataRepresentation: dataRepresentation, authenticationContext: context)
+    }
+
+    func newSecureEnclavePrivateKey(accessControl: SecAccessControl) throws
+      -> SecureEnclavePrivateKey
+    {
+      return try SecureEnclave.P256.KeyAgreement.PrivateKey(
+        accessControl: accessControl, authenticationContext: context)
+    }
+
+    func newEphemeralPrivateKey() -> P256.KeyAgreement.PrivateKey {
+      return P256.KeyAgreement.PrivateKey()
+    }
+  }
+
+  extension SecureEnclave.P256.KeyAgreement.PrivateKey: SecureEnclavePrivateKey {
+  }
+
+#else
+
+  class CryptoKitCrypto: Crypto {
+    var isSecureEnclaveAvailable: Bool {
+      return false
+    }
+
+    func newSecureEnclavePrivateKey(dataRepresentation: Data) throws -> SecureEnclavePrivateKey {
+      throw Plugin.Error.seUnsupported
+    }
+
+    func newSecureEnclavePrivateKey(accessControl: SecAccessControl) throws
+      -> SecureEnclavePrivateKey
+    {
+      throw Plugin.Error.seUnsupported
+    }
+
+    func newEphemeralPrivateKey() -> P256.KeyAgreement.PrivateKey {
+      return P256.KeyAgreement.PrivateKey()
+    }
+  }
+
+#endif