C#加密算法HmacSHA256,SHA256

public static string SHA256Encrypt(string strIN)
{
    //string strIN = getstrIN(strIN);
    byte[] tmpByte;
    SHA256 sha256 = new SHA256Managed();
    tmpByte = sha256.ComputeHash(GetKeyByteArray(strIN));

    StringBuilder rst = new StringBuilder();
    for(int i = 0; i"x2"));   
    }
    sha256.Clear();
    return rst.ToString();
    //return GetStringValue(tmpByte);
}

private static string GetStringValue(byte[] Byte)
{
    string tmpString = "";
    UTF8Encoding Asc = new UTF8Encoding();
    tmpString = Asc.GetString(Byte);
    return tmpString;
}

private static byte[] GetKeyByteArray(string strKey)
{
    UTF8Encoding Asc = new UTF8Encoding();
    int tmpStrLen = strKey.Length;
    byte[] tmpByte = new byte[tmpStrLen - 1];
    tmpByte = Asc.GetBytes(strKey);
    return tmpByte;
}

private static string HmacSHA256(string message, string secret)
{
    secret = secret ?? "";
    var encoding = new System.Text.UTF8Encoding();
    byte[] keyByte = encoding.GetBytes(secret);
    byte[] messageBytes = encoding.GetBytes(message);
    using (var hmacsha256 = new HMACSHA256(keyByte))
    {
        byte[] hashmessage = hmacsha256.ComputeHash(messageBytes);
        return Convert.ToBase64String(hashmessage);
    }
}

private static string Base64(string message)
{
    System.Text.Encoding encode = System.Text.Encoding.UTF8;
    byte[] bytedata = encode.GetBytes(message);
    string strPath = Convert.ToBase64String(bytedata, 0, bytedata.Length);
    return strPath;
}