Facebook实时更新:在C#中验证X-Hub-Signature SHA1签名

Question

当Facebook发送实时更新时,它们在HTTP标头中包含X-Hub-Signature.根据他们的文档(http://developers.facebook.com/docs/api/realtime),他们使用SHA1和应用程序密钥作为密钥.我试着像这样验证签名:

public void MyAction() {
  string signature = request.Headers["X-Hub-Signature"];
  request.InputStream.Position = 0;
  StreamReader reader = new StreamReader(request.InputStream);
  string json = reader.ReadToEnd();

  var hmac = SignWithHmac(UTF8Encoding.UTF8.GetBytes(json), UTF8Encoding.UTF8.GetBytes("MySecret"));
  var hmacBase64 = ToUrlBase64String(hmac);

  bool isValid = signature.Split('=')[1] == hmacBase64;

}


    private static byte[] SignWithHmac(byte[] dataToSign, byte[] keyBody) {
        using (var hmacAlgorithm = new System.Security.Cryptography.HMACSHA1(keyBody)) {
            hmacAlgorithm.ComputeHash(dataToSign);
            return hmacAlgorithm.Hash;
        }
    }

    private static string ToUrlBase64String(byte[] Input) {
        return Convert.ToBase64String(Input).Replace("=", String.Empty)
                                            .Replace('+', '-')
                                            .Replace('/', '_');
    }

但我似乎无法让这一点得到验证.对我做错了什么的想法？

提前致谢.

Answer 1

如果有人需要这些信息:

凯尔文提供的可能有用,但看起来非常麻烦.您只需使用ConvertToHexadecimal函数,而不是使用ToUrlBase64String函数.

查看下面的完整更新代码:

public void MyAction() {
    string signature = request.Headers["X-Hub-Signature"];
    request.InputStream.Position = 0;
    StreamReader reader = new StreamReader(request.InputStream);
    string json = reader.ReadToEnd();

    var hmac = SignWithHmac(UTF8Encoding.UTF8.GetBytes(json), UTF8Encoding.UTF8.GetBytes("MySecret"));
    var hmacHex = ConvertToHexadecimal(hmac);

    bool isValid = signature.Split('=')[1] == hmacHex ;

}


private static byte[] SignWithHmac(byte[] dataToSign, byte[] keyBody) {
    using (var hmacAlgorithm = new System.Security.Cryptography.HMACSHA1(keyBody)) {
        return hmacAlgorithm.ComputeHash(dataToSign);
    }
}

private static string ConvertToHexadecimal(IEnumerable<byte> bytes)
{
    var builder = new StringBuilder();
    foreach (var b in bytes)
    {
        builder.Append(b.ToString("x2"));
    }

    return builder.ToString();
 }