在Windows应用商店中使用hmacsha256

Question

我正在将Windows Phone 7.1应用程序迁移/转换/重建为Windows 8商店应用程序.

我在de WP7应用程序中使用的一种方法是给我带来麻烦:

private byte[] GetSHA256Key(string data, string secretKey)
{
    byte[] value = Encoding.UTF8.GetBytes(data);
    byte[] secretKeyBytes = Encoding.UTF8.GetBytes(secretKey);

    HMACSHA256 hmacsha256 = new HMACSHA256(secretKeyBytes);

    byte[] resultBytes = hmacsha256.ComputeHash(value);

    return resultBytes;
}

查看Windows应用商店应用的文档,我想出了这个新代码,我希望能给出相同的结果.但不是.我做错了什么.但是什么？

private byte[] GetSHA256Key(string value, string secretKey)
{
        // Create a MacAlgorithmProvider object for the specified algorithm.
        MacAlgorithmProvider objMacProv = MacAlgorithmProvider.OpenAlgorithm(MacAlgorithmNames.HmacSha256);

        // Create a buffer that contains the message to be signed.
        IBuffer valueBuffer = CryptographicBuffer.ConvertStringToBinary(value, BinaryStringEncoding.Utf8);

        // Create a key to be signed with the message.
        IBuffer buffKeyMaterial = CryptographicBuffer.ConvertStringToBinary(secretKey, BinaryStringEncoding.Utf8);
        CryptographicKey cryptographicKey = objMacProv.CreateKey(buffKeyMaterial);

        // Sign the key and message together.
        IBuffer bufferProtected = CryptographicEngine.Sign(cryptographicKey, valueBuffer);

        DataReader dataReader = DataReader.FromBuffer(bufferProtected);
        byte[] bytes = new byte[bufferProtected.Length];
        dataReader.ReadBytes(bytes);

        return bytes;
}

我不是密码学方面的专家.我不确定我在做什么.也许有人可以帮助我.

Thanx,JP

Answer 1

using System.Runtime.InteropServices.WindowsRuntime;

private string GetSHA256Key(byte[] secretKey, string value)
{
    var objMacProv = MacAlgorithmProvider.OpenAlgorithm(MacAlgorithmNames.HmacSha256);
    var hash = objMacProv.CreateHash(secretKey.AsBuffer());
    hash.Append(CryptographicBuffer.ConvertStringToBinary(value, BinaryStringEncoding.Utf8));
    return CryptographicBuffer.EncodeToBase64String(hash.GetValueAndReset());
}

Answer 2

new HMACSHA256(keydata) 使用密钥作为输入，而 MacAlgorithmProvider.CreateKey() 使用输入作为“用于帮助生成密钥的随机数据”，这不是 HMAC 算法的密钥。