Changed to use builtin copy.

pkg/crypto/cipher/cts/cts.mpcl

@@ -42,37 +42,37 @@ func EncryptAES128(key [16]byte, iv [aes.BlockSize]byte, data []byte) []byte {
 		panic("cts.EncryptAES128: input must be at least 2 block")
 	}
 	var block [aes.BlockSize]byte
-	block = memcpy(block, 0, iv, 0)
+	copy(block, iv)
 
 	var plain [aes.BlockSize]byte
 	var cipher [len(data)]byte
 
 	// Standard CBC for the first numBlocks-1 blocks.
 	for i := 0; i < numBlocks-1; i++ {
-		plain = memcpy(plain, 0, data, i*aes.BlockSize)
+		copy(plain, data[i*aes.BlockSize:])
 		for j := 0; j < aes.BlockSize; j++ {
 			plain[j] ^= block[j]
 		}
 		block = aes.EncryptBlock(key, plain)
 		if i < numBlocks-2 {
 			// Store standard CBC output block.
-			cipher = memcpy(cipher, i*aes.BlockSize, block, 0)
+			copy(cipher[i*aes.BlockSize:], block)
 		} else {
 			// Store last ciphertext block.
-			cipher = memcpy(cipher, (numBlocks-1)*aes.BlockSize, block, 0)
+			copy(cipher[(numBlocks-1)*aes.BlockSize:], block)
 		}
 	}
 
 	// Create last input block.
-	plain = memcpy(plain, 0, data, (numBlocks-1)*aes.BlockSize)
+	copy(plain, data[(numBlocks-1)*aes.BlockSize:])
 	for i := tail; i < aes.BlockSize; i++ {
 		plain[i] = 0
 	}
 	for j := 0; j < aes.BlockSize; j++ {
 		plain[j] ^= block[j]
 	}
 	block = aes.EncryptBlock(key, plain)
-	cipher = memcpy(cipher, (numBlocks-2)*aes.BlockSize, block, 0)
+	copy(cipher[(numBlocks-2)*aes.BlockSize:], block)
 
 	return cipher
 }
@@ -100,43 +100,36 @@ func DecryptAES128(key [16]byte, iv [aes.BlockSize]byte, data []byte) []byte {
 
 	// Standard CBC for the first numBlocks-2 blocks.
 	for i := 0; i < numBlocks-2; i++ {
-		cipher = memcpy(cipher, 0, data, i*aes.Blocks)
+		copy(cipher, data[i*aes.Blocks:])
 		block = aes.DecryptBlock(key, cipher)
 		for j := 0; j < aes.BlockSize; j++ {
 			block[j] ^= iv[j]
 		}
-		plain = memcpy(plain, i*aes.BlockSize, block, 0)
-		iv = memcpy(iv, 0, cipher, 0)
+		copy(plain[i*aes.BlockSize:], block)
+		copy(iv, cipher)
 	}
 
 	// Decrypt second-to-last cipher block.
-	cipher = memcpy(cipher, 0, data, (numBlocks-2)*aes.BlockSize)
+	copy(cipher, data[(numBlocks-2)*aes.BlockSize:])
 	tmp := aes.DecryptBlock(key, cipher)
 
 	// Create padded last cipher block.
-	tmp2 = memcpy(tmp2, 0, data, (numBlocks-1)*aes.BlockSize)
-	tmp2 = memcpy(tmp2, tail, tmp, tail)
+	copy(tmp2, data[(numBlocks-1)*aes.BlockSize:])
+	copy(tmp2[tail:], tmp[tail:])
 
 	// Decrypt second-to-last block.
 	block = aes.DecryptBlock(key, tmp2)
 	for j := 0; j < aes.BlockSize; j++ {
 		block[j] ^= iv[j]
 	}
-	plain = memcpy(plain, (numBlocks-2)*aes.BlockSize, block, 0)
-	iv = memcpy(iv, 0, tmp2, 0)
+	copy(plain[(numBlocks-2)*aes.BlockSize:], block)
+	copy(iv, tmp2)
 
 	// Finalize last block.
 	for j := 0; j < aes.BlockSize; j++ {
 		tmp[j] ^= iv[j]
 	}
-	plain = memcpy(plain, (numBlocks-1)*aes.BlockSize, tmp, 0)
+	copy(plain[(numBlocks-1)*aes.BlockSize:], tmp)
 
 	return plain
 }
-
-func memcpy(dst []byte, dstOfs int, src []byte, srcOfs int) []byte {
-	for i := 0; srcOfs+i < len(src) && dstOfs+i < len(dst); i++ {
-		dst[dstOfs+i] = src[srcOfs+i]
-	}
-	return dst
-}