java HmacSHA1哈希与swift（IOS）不匹配

Question

Java版：

public static byte[] computeSignature(String algorithm, byte[] data, byte[] sharedSecret) {
    try {
        SecretKey secretKey = new SecretKeySpec(sharedSecret, algorithm);
        Mac mac = Mac.getInstance(algorithm);
        mac.init(secretKey);
        return Base64.encode(mac.doFinal(data));
    } catch (NoSuchAlgorithmException e) {
        // 
    } catch (InvalidKeyException e) {
        //
    }
}

Swift版本：

func hmac(key: String) -> String {
    let inputData: NSData = self.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!
    let keyData: NSData = key.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)!

    let algorithm = HMACAlgorithm.SHA1
    let digestLen = CC_SHA1_DIGEST_LENGTH
    let result = UnsafeMutablePointer<CUnsignedChar>.alloc(digestLen)

    CCHmac(CCHmacAlgorithm(kCCHmacAlgSHA1), keyData.bytes, keyData.length, inputData.bytes, inputData.length, result)
    let data = NSData(bytes: result, length: digestLen)
    result.destroy()
    return data.base64EncodedStringWithOptions(NSDataBase64EncodingOptions.Encoding64CharacterLineLength)
}

这是使用CryptoJs的javascript版本，它生成与java代码相同的hmacsha1哈希：https://jsfiddle.net/333VW/