如何使用C#获得X509Certificate2对象的签名

本文关键字：对象 X509Certificate2 何使用 获得 | 更新日期: 2023-09-27 18:21:56

我需要用C#从证书中获得签名和用于创建该签名的算法。

我能做到吗？如果是，如何？

如何使用C#获得X509Certificate2对象的签名

我现在正在开发具有类似功能的应用程序。我真的很失望为什么微软没有在X509Certificate2类中添加属性签名

我知道如何通过bouncycastle 做到这一点

从那里拿走http://www.bouncycastle.org/csharp/

然后添加代码

using System;
using System.Security.Cryptography.X509Certificates;
using bcrypto = Org.BouncyCastle.X509;


var cert = new X509Certificate2("c:''temp''0c50000343119659.cer");
var certParser = new bcrypto.X509CertificateParser();
var privateCertBouncy = certParser.ReadCertificate(cert.GetRawCertData());
var xx = privateCertBouncy.GetSignature();
Array.Reverse(xx);
//Signature
Console.WriteLine(BitConverter.ToString(xx));
//algorithm
Console.WriteLine(privateCertBouncy.SigAlgName);
Console.ReadLine();

您将不得不求助于的Bouncy Castle

https://github.com/bcgit/bc-csharp/blob/master/crypto/src/x509/X509Certificate.cs#L240

它的X509Certificate类允许您访问此属性。

您可以使用AsnDecoder以及RFC3280第4.1节中有关X509 v3结构的信息。将此功能的输出与openssl x509 -noout -text -in <pem file> 进行比较

/// <summary>
/// RFC3280 Section 4.1
/// Depth 1 of the X509 v3 cert is
/// Certificate  ::=  SEQUENCE  {
///     tbsCertificate TBSCertificate,
///     signatureAlgorithm   AlgorithmIdentifier,
///     signatureValue BIT STRING
/// }
///
/// https://www.rfc-editor.org/rfc/rfc3280#section-4.1
/// </summary>
public static byte[] Signature(this X509Certificate2 certificate)
{
    var signedData = certificate.RawDataMemory;
    AsnDecoder.ReadSequence(
        signedData.Span,
        AsnEncodingRules.BER,
        out var offset,
        out var length,
        out _
    );
    var certificateSpan = signedData.Span[offset..(offset + length)];
    AsnDecoder.ReadSequence(
        certificateSpan,
        AsnEncodingRules.BER,
        out var tbsOffset,
        out var tbsLength,
        out _
    );
    var offsetSpan = certificateSpan[(tbsOffset + tbsLength)..];
    AsnDecoder.ReadSequence(
        offsetSpan,
        AsnEncodingRules.BER,
        out var algOffset,
        out var algLength,
        out _
    );
    return AsnDecoder.ReadBitString(
        offsetSpan[(algOffset + algLength)..],
        AsnEncodingRules.BER,
        out _,
        out _
    );
}
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