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我在我的 Windows 机器上成功运行了这段代码（Win 10 x64，运行 dotnet 4.7.2）。它生成一个 EC 密钥对（“P-256”），使用 SHA-256 对明文进行散列，使用 ec 私钥对散列进行签名，并使用 ec 公钥针对散列明文验证签名。

我得到了这个输出，所以一切正常：

EC signature curve secp256r1 / P-256 string
dataToSign: The quick brown fox jumps over the lazy dog
* * * sign the plaintext with the EC private key * * *
EC keysize: 256
signature (Base64): cwLBRSt1vtO33tHWcTdx1OTu9lBFXHEJgvdRyDUynLLE5eMakUZUAKLwaJvYoS7NBylx2Zz0+G6dvgJ6xv5qNA==
* * *verify the signature against hash of plaintext with the EC public key * * *
signature verified: True

现在我正在尝试找到任何能够运行代码的在线编译器。我最喜欢的编译器（https://repl.it/，Mono C# 编译器版本 6.8.0.123，完整代码：https://repl.it/@javacrypto/EcSignatureFull#main.cs）遇到了这个错误：

Unhandled Exception:
System.NotImplementedException: The method or operation is not implemented.
  at EcSignatureString.Main () [0x00036] in <13e2ad358a924efc874a89efad35ffe7>:0
[ERROR] FATAL UNHANDLED EXCEPTION: System.NotImplementedException: The method or operation is not implemented.
  at EcSignatureString.Main () [0x00036] in <13e2ad358a924efc874a89efad35ffe7>:0
exit status 1

使用另一个平台（https://dotnetfiddle.net/，Compiler .net 5，完整代码：https://dotnetfiddle.net/lSPpjz）给出了类似的错误：

Unhandled exception. System.PlatformNotSupportedException: Windows Cryptography Next Generation (CNG) is not supported on this platform.
   at System.Security.Cryptography.ECDsaCng..ctor(Int32 keySize)
   at EcSignatureString.Main()
Command terminated by signal 6

所以我的问题是：是否有任何可用的在线编译器能够运行代码？

我认为我的问题可能与 SO 无关——在这种情况下——是否还有其他 stackexchange-site 可以更好地解决我的问题？

警告：以下代码没有异常处理，仅用于教育目的：

using System;
using System.Security.Cryptography;

class EcSignatureString {
    static void Main() {

    Console.WriteLine("EC signature curve secp256r1 / P-256 string");
    string dataToSignString = "The quick brown fox jumps over the lazy dog";
    byte[] dataToSign = System.Text.Encoding.UTF8.GetBytes(dataToSignString);
    Console.WriteLine("dataToSign: " + dataToSignString);
    try {
        Console.WriteLine("\n* * * sign the plaintext with the EC private key * * *");

        ECDsaCng ecDsaKeypair = new ECDsaCng(256);
        Console.WriteLine("EC keysize: " + ecDsaKeypair.KeySize);

        byte[] hashedData = null;
        byte[] signature = null;
        // create new instance of SHA256 hash algorithm to compute hash
        HashAlgorithm hashAlgo = new SHA256Managed();
        hashedData = hashAlgo.ComputeHash(dataToSign);

        // sign Data using private key
        signature = ecDsaKeypair.SignHash(hashedData);
        string signatureBase64 = Convert.ToBase64String(signature);
        Console.WriteLine("signature (Base64): " + signatureBase64);

        // get public key from private key
        string ecDsaPublicKeyParametersXml = ecDsaKeypair.ToXmlString(ECKeyXmlFormat.Rfc4050);

        // verify
        Console.WriteLine("\n* * *verify the signature against hash of plaintext with the EC public key * * *");
        ECDsaCng ecDsaVerify = new ECDsaCng();
        bool signatureVerified = false;
        ecDsaVerify.FromXmlString(ecDsaPublicKeyParametersXml, ECKeyXmlFormat.Rfc4050);
        signatureVerified = ecDsaVerify.VerifyHash(hashedData, signature);
        Console.WriteLine("signature verified: " + signatureVerified);
        }
        catch(ArgumentNullException) {
            Console.WriteLine("The data was not signed or verified");
        }
    }
}
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1 回答 1

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Microsoft 已决定必须将加密和散列完全委托给操作系统（在 .NET Framework 中是一半），因此现在 .NET 5（和 .NET Core）有多个用于加密的后端（例如，ECDsa它有ECDsaCng这样的用途Windows 服务和ECDsaOpenSsl使用 OpenSsl 的 Linux/MacO（参见MSDN）

现在......您的问题的解决方案是使用ECDsa该类并让它选择它的后端。它有一些问题。您不能轻松地将密钥导出为 xml 格式，也不能轻松地将它们导出为 PEM 格式。您可以轻松地将它们导出为byte[]，并且可以轻松地从 PEM 格式导入它们。这并不是一个真正的大问题，因为您很少需要生成密钥，并且通常您的程序从外部源接收其密钥，或者如果它自己生成它们，它可以将它们保存为二进制格式以便以后重用它们。

var dataToSignString = "Hello world!";
var dataToSign = Encoding.UTF8.GetBytes(dataToSignString);

Console.WriteLine("dataToSign: " + dataToSignString);

try
{
    Console.WriteLine("\n* * * sign the plaintext with the EC private key * * *");

    var ecDsaKeypair = ECDsa.Create(ECCurve.NamedCurves.nistP256);

    // Normally here:
    //ecDsaKeypair.ImportFromPem()

    Console.WriteLine("EC keysize: " + ecDsaKeypair.KeySize);

    byte[] hashedData = null;
    byte[] signature = null;
    // create new instance of SHA256 hash algorithm to compute hash
    HashAlgorithm hashAlgo = new SHA256Managed();
    hashedData = hashAlgo.ComputeHash(dataToSign);

    // sign Data using private key
    signature = ecDsaKeypair.SignHash(hashedData);
    string signatureBase64 = Convert.ToBase64String(signature);
    Console.WriteLine("signature (Base64): " + signatureBase64);

    // get public key from private key
    string ecDsaPublicKeyParameters = Convert.ToBase64String(ecDsaKeypair.ExportSubjectPublicKeyInfo());

    // verify
    Console.WriteLine("\n* * *verify the signature against hash of plaintext with the EC public key * * *");

    var ecDsaVerify = ECDsa.Create(ECCurve.NamedCurves.nistP256);
    bool signatureVerified = false;

    // Normally here:
    //ecDsaKeypair.ImportFromPem()
    var publicKey = Convert.FromBase64String(ecDsaPublicKeyParameters);
    ecDsaVerify.ImportSubjectPublicKeyInfo(publicKey, out _);

    signatureVerified = ecDsaVerify.VerifyHash(hashedData, signature);
    Console.WriteLine("signature verified: " + signatureVerified);
}
catch (ArgumentNullException)
{
    Console.WriteLine("The data was not signed or verified");
}

关于.NET Core 的 githubFrom/ToXmlFormat上当前对它们的评论是：

// There is currently not a standard XML format for ECC keys, so we will not implement the default
// To/FromXmlString so that we're not tied to one format when a standard one does exist. Instead we'll
// use an overload which allows the user to specify the format they'd like to serialize into.

嗯，从完成的一些测试来看，以 PEM 格式导出似乎很容易：

public static IEnumerable<string> Split(string str, int chunkSize)
{
    for (int i = 0; i < str.Length; i += chunkSize)
    {
        yield return str.Substring(i, Math.Min(chunkSize, str.Length - i));
    }
}

进而

string b64privateKey = Convert.ToBase64String(ecDsaKeypair.ExportPkcs8PrivateKey());
b64privateKey = string.Join("\r\n", Split(b64privateKey, 64));
string pemPrivateKey = "-----BEGIN PRIVATE KEY-----\r\n" + b64privateKey + "\r\n-----END PRIVATE KEY-----";

或者

string b64publicKey = Convert.ToBase64String(ecDsaKeypair.ExportSubjectPublicKeyInfo());
b64publicKey = string.Join("\r\n", Split(b64publicKey, 64));
string pemPublicKey = "-----BEGIN PUBLIC KEY-----\r\n" + b64publicKey + "\r\n-----END PUBLIC KEY-----";

（请注意，我必须手动将字符串拆分为 64 个字符的块，这是 rfc7468 中给出的确切数字，因为Convert.ToBase64String()仅支持 76 行长度）

于 2020-12-28T10:07:38.087 回答