C# 使用帶有 SHA256 證書的 ECDSA 進行簽名驗證

Question

我正在嘗試使用 C# 和內置的 Crypto 庫來驗證使用 EC 密鑰 + SHA256 創建的簽名。 這就是我正在做的事情。

我使用 openssl 創建了一個私鑰和相應的證書：

$ openssl ecparam -genkey -name prime256v1 -out ca.key
$ openssl req -x509 -new -SHA256 -nodes -key ca.key -days 36500 -out ca.crt

這是我正在使用的鍵（別擔心，它們並不重要）：

$ cat ca.key 
-----BEGIN EC PARAMETERS-----
BggqhkjOPQMBBw==
-----END EC PARAMETERS-----
-----BEGIN EC PRIVATE KEY-----
MHcCAQEEIHd3OvRV1nEnoDxGzzemX1x8l2rHasWH3L/LflUGg5vloAoGCCqGSM49
AwEHoUQDQgAE7f1xwQL5m/UcN4zL+zsly6V1g3/wNcL5TdCfWt0XfnUfg0x+RsIf
1uerBnhrmhH0cN9o0xfXg5B3hURFlXVuEQ==
-----END EC PRIVATE KEY-----

$ cat ca.crt 
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

然后我有一個包含字符串“Hello”的簡單數據文件。 然后我使用 openssl 簽署該文件，如下所示：

$ openssl dgst -sha256 -sign ca.key data.txt > sig
$ base64 sig 
MEUCIQD5593C/NBhHA1DILT72gjhGj/lKjom9vYP+JbuypBrxQIgNAjYT1LihEpPbUhe1n9ccUHQ
vw676bGqOTEU/25qcRQ=

然后我可以通過首先從證書中提取公鑰然后使用它來驗證簽名來驗證簽名：

$ openssl x509 -pubkey -noout -in ca.crt > ca.pub
$ cat ca.pub 
-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE7f1xwQL5m/UcN4zL+zsly6V1g3/w
NcL5TdCfWt0XfnUfg0x+RsIf1uerBnhrmhH0cN9o0xfXg5B3hURFlXVuEQ==
-----END PUBLIC KEY-----
$ openssl dgst -verify ca.pub -sha256 -signature sig data.txt 
Verified OK

然后我嘗試使用 C# (.NET Core 3.1) 來驗證簽名。 代碼如下：

using System;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Text;

namespace security_sandbox
{
    class Program
    {
        static void Main(string[] args)
        {
            var certData = Encoding.ASCII.GetBytes(
                @"-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----");

            var cert = new X509Certificate2(certData);
            var ecdsa = cert.GetECDsaPublicKey();

            var data = Encoding.ASCII.GetBytes("Hello");
            var signature = Convert.FromBase64String("MEUCIQD5593C/NBhHA1DILT72gjhGj/lKjom9vYP+JbuypBrxQIgNAjYT1LihEpPbUhe1n9ccUHQvw676bGqOTEU/25qcRQ=");

            var success = ecdsa.VerifyData(data, signature, HashAlgorithmName.SHA256);

            if (success)
            {
                Console.WriteLine("Verified");
            } else
            {
                Console.WriteLine("Failed");
            }
        }
    }
}

不幸的是，它總是無法通過驗證。 錯誤在哪里？

Answer 1

.NET 中缺乏與 PEM/OpenSSL 兼容的操作工具被證明是非常令人沮喪的。 我最終使用Bouncy Castle加載證書或公鑰，然后使用它來驗證我的 ASN 簽名。 這是一個完整的工作代碼示例，演示了如何使用證書和 PEM 公鑰以及使用 ASN 編碼的簽名來執行簽名驗證。

using System;
using System.IO;
using System.Text;
using Org.BouncyCastle.Crypto;
using Org.BouncyCastle.OpenSsl;
using Org.BouncyCastle.Security;
using Org.BouncyCastle.X509;

namespace security_sandbox
{
    class Program
    {
        static void Main(string[] args)
        {

            var certificateString =  @"-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----";
            var pemreader = new PemReader(new StringReader(certificateString));
            var cert = (X509Certificate)pemreader.ReadObject();

            // Alternatively, load the public key directly
            var pubkeyString = 
@"-----BEGIN PUBLIC KEY-----
MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAE7f1xwQL5m/UcN4zL+zsly6V1g3/w
NcL5TdCfWt0XfnUfg0x+RsIf1uerBnhrmhH0cN9o0xfXg5B3hURFlXVuEQ==
-----END PUBLIC KEY-----";
            pemreader = new PemReader(new StringReader(pubkeyString));
            var pubkey = (AsymmetricKeyParameter)pemreader.ReadObject();

            var data = "Hello";
            var signature = Convert.FromBase64String("MEUCIQD5593C/NBhHA1DILT72gjhGj/lKjom9vYP+JbuypBrxQIgNAjYT1LihEpPbUhe1n9ccUHQvw676bGqOTEU/25qcRQ=");

            // Verify using the public key
            var signer = SignerUtilities.GetSigner("SHA-256withECDSA");
            signer.Init(false, pubkey);
            signer.BlockUpdate(Encoding.ASCII.GetBytes(data), 0, data.Length);
            var success = signer.VerifySignature(signature);

            if (success) {
                Console.WriteLine("Signature verified successfully using public key");
            } else {
                Console.WriteLine("Failed to verify signature using public key");
            }

            // Verify using the certificate - the certificate's public key is extracted using the GetPublicKey method.
            signer.Init(false, cert.GetPublicKey());
            signer.BlockUpdate(Encoding.ASCII.GetBytes(data), 0, data.Length);
            success = signer.VerifySignature(signature);

            if (success) {
                Console.WriteLine("Signature verified successfully using certificate");
            } else {
                Console.WriteLine("Failed to verify signature using certificate");
            }
        }
    }
}