Allow CMAC with any Cipher (OMAC1). #809

Sources/CryptoSwift/CMAC.swift

@@ -30,10 +30,15 @@ public class CMAC: Authenticator {
 
   // MARK: Authenticator
 
+  // AES-CMAC
   public func authenticate(_ bytes: Array<UInt8>) throws -> Array<UInt8> {
-    let aes = try AES(key: Array(key), blockMode: CBC(iv: CMAC.Zero), padding: .noPadding)
+    let cipher = try AES(key: Array(key), blockMode: CBC(iv: CMAC.Zero), padding: .noPadding)
+    return try self.authenticate(bytes, cipher: cipher)
+  }
 
-    let l = try aes.encrypt(CMAC.Zero)
+  // CMAC using a Cipher
+  public func authenticate(_ bytes: Array<UInt8>, cipher: Cipher) throws -> Array<UInt8> {
+    let l = try cipher.encrypt(CMAC.Zero)
     var subKey1 = self.leftShiftOneBit(l)
     if (l[0] & 0x80) != 0 {
       subKey1 = xor(CMAC.Rb, subKey1)
@@ -67,11 +72,11 @@ public class CMAC: Authenticator {
     var y = Array<UInt8>(repeating: 0x00, count: CMAC.BlockSize)
     for block in blocks {
       y = xor(block, x)
-      x = try aes.encrypt(y)
+      x = try cipher.encrypt(y)
     }
     // the difference between CMAC and CBC-MAC is that CMAC xors the final block with a secret value
     y = self.process(lastBlock: lastBlock, with: x)
-    return try aes.encrypt(y)
+    return try cipher.encrypt(y)
   }
 
   func process(lastBlock: ArraySlice<UInt8>, with x: [UInt8]) -> [UInt8] {