Javascript ECDsaCng通过Windows上的C#验证来自Android WebAuthn的数据椭圆曲线签名

无论我做什么，我都无法让C#ECDsaCng VerifyData方法返回true。类似的代码适用于RSA签名和来自Windows Hello的数据，但Android/Samsung的EC加密让我感到困惑

断言.签名：-MEYCIQDi0OGHK2CRFpel6RWq26IjyWmJCfJnnaYvGWL/NBC6AWIZNWESDJ5UZFXDKVHENGYCKAEUZGJEYKIVJGFF/SNyd

assertion.ClientDataJSON:-{“类型”：“webauthn.get”，“挑战”：“ZXLKAGJHY2LPAPJVXPJMU5PSXNJBLI1Y0NJNKLRFHWQ0O5LMV5SMXLSEFPT2PFMK1UVTVOAK14TWPBC0LTBHPJEUK2SWXSBGMZUXVJL0SWL3AVLYVMTJAM9PVKDWEMRDNWPIMJRJBPZLRL3RL1DBCEPJNFJJJRJRJJJRHDGN01MS1VPUKFXWFL0BDBRD1BKQUJVQ”，“原产地”：”https://localhost:3000，“androidPackageName”：“com.android.chrome”}

pubKey.x:-CeE16bdD0ga/oiy/zFL1c70Cp/9me+HZzggzlTooWzU=

pubKey.y:-N5l+MynIqzxgut+phBUNIOcI7DIv2uRXHkLCesK90Cg=

以下是代码段：-

        byte[] data = new byte[authData.Length + hashValClientData.Length];
        Buffer.BlockCopy(authData, 0, data, 0, authData.Length);
        Buffer.BlockCopy(hashValClientData, 0, data, authData.Length, hashValClientData.Length);

        byte[] sig = Convert.FromBase64String(assertion.Signature);

        if (pubKey.kty == "EC")
        {
            byte[] ECDsaSig = convertFromASN1(sig);
            var keyType = new byte[] { 0x45, 0x43, 0x53, 0x31 }; // BCRYPT_ECDSA_PUBLIC_P256_MAGIC {E, C, S, 1}
            var keyLength = new byte[] { 0x20, 0x00, 0x00, 0x00 }; // Key length 32
            byte[] keyImport = new byte [72];
            Buffer.BlockCopy(keyType, 0, keyImport, 0, keyType.Length);
            Buffer.BlockCopy(keyLength, 0, keyImport, keyType.Length, keyLength.Length);
            Buffer.BlockCopy(Convert.FromBase64String(pubKey.x), 0, keyImport, 8, 32);
            Buffer.BlockCopy(Convert.FromBase64String(pubKey.y), 0, keyImport, 40, 32);

            try
            {
                using (ECDsaCng dsa = new ECDsaCng(CngKey.Import(keyImport, CngKeyBlobFormat.EccPublicBlob)))
                {
                    dsa.HashAlgorithm = CngAlgorithm.Sha256;
                    if (dsa.VerifyData(data, ECDsaSig))
                    {
                        Console.WriteLine("The signature is valid.");
                    }
                    else
                    {
                        Console.WriteLine("The signature is not valid.");
                        return FAIL_STATUS;
                    }
                }
            }
            catch (Exception e)
            {
                return FAIL_STATUS;
            }
        } 

阅读后，我意识到我必须将ASN.1签名转换为ECDsa友好格式，因此我这样做：-

    internal byte[] convertFromASN1(byte[] sig)
    {
        const int DER = 48;
        const int LENGTH_MARKER = 2;

        if (sig.Length < 6 || sig[0] != DER || sig[1] != sig.Length - 2 || sig[2] != LENGTH_MARKER || sig[sig[3] + 4] != LENGTH_MARKER)
            throw new ArgumentException("Invalid signature format.", "sig");

        int rLen = sig[3];
        int sLen = sig[rLen + 5];

        byte[] newSig = new byte[rLen + sLen];
        Buffer.BlockCopy(sig, 4, newSig, 0, rLen);
        Buffer.BlockCopy(sig, 6 + rLen, newSig, rLen, sLen);

        return newSig;
    }

内部字节[]convertFromASN1（字节[]sig）
{
常数int DER=48；
const int LENGTH_MARKER=2；
如果（sig.Length<6 | | sig[0]！=DER | | sig[1]！=sig.Length-2 | | sig[2]！=Length| | sig[sig[3]+4]！=Length|MARKER）
抛出新的ArgumentException（“无效的签名格式。”，“sig”）；
int-rLen=sig[3]；
int sLen=sig[rLen+5]；
byte[]newSig=新字节[rLen+sLen]；
块拷贝（sig，4，newSig，0，rLen）；
块拷贝（sig，6+rLen，newSig，rLen，sLen）；
返回newSig；
}

---

但仍然没有乐趣：-（我做错了什么？请帮助。（用SHA256散列的ClientData）

类似的方法应该可以：

if (pubKey.kty == "EC")
{
    byte[] ecDsaSig = convertFromASN1(sig);

    var point = new ECPoint
    {
        X = Convert.FromBase64String(pubKey.x),
        Y = Convert.FromBase64String(pubKey.y),
    };

    var ecparams = new ECParameters
    {
        Q = point,
        Curve = ECCurve.NamedCurves.nistP256
    };

    try
    {
        using (ECDsa ecdsa = ECDsa.Create(ecparams))
        {
            if (ecdsa.VerifyData(data, ecDsaSig, HashAlgorithmName.SHA256)
            {
                Console.WriteLine("The signature is valid.");
            }
            else
            {
                Console.WriteLine("The signature is not valid.");
                return FAIL_STATUS;
            }
        }
    }
    catch (Exception e)
    {
        return FAIL_STATUS;
    }
} 

将ASN.1转换为.NET想要的IEEE p-1363格式可能非常棘手。一些指导和建议

如果你拿样本sig，你可以更好地想象分解，X从1025开始，以3227结束，Y从9987开始，以1469结束

---

这就是我目前正在做的事情。

类似的事情应该会起作用：

if (pubKey.kty == "EC")
{
    byte[] ecDsaSig = convertFromASN1(sig);

    var point = new ECPoint
    {
        X = Convert.FromBase64String(pubKey.x),
        Y = Convert.FromBase64String(pubKey.y),
    };

    var ecparams = new ECParameters
    {
        Q = point,
        Curve = ECCurve.NamedCurves.nistP256
    };

    try
    {
        using (ECDsa ecdsa = ECDsa.Create(ecparams))
        {
            if (ecdsa.VerifyData(data, ecDsaSig, HashAlgorithmName.SHA256)
            {
                Console.WriteLine("The signature is valid.");
            }
            else
            {
                Console.WriteLine("The signature is not valid.");
                return FAIL_STATUS;
            }
        }
    }
    catch (Exception e)
    {
        return FAIL_STATUS;
    }
} 

将ASN.1转换为.NET想要的IEEE p-1363格式可能非常棘手。一些指导和建议

如果你拿样本sig，你可以更好地想象分解，X从1025开始，以3227结束，Y从9987开始，以1469结束

---

我现在也是这样做的。

像往常一样，亚历克斯，你是一个血腥的传奇。Stackoverflow更适合你在这里。像往常一样，亚历克斯，你是一个血腥的传奇。Stackoverflow更适合你在这里。