Question

我正在将Visual Studio 2019与c＃和Bouncy Castle版的1.8.5一起使用。我已经能够成功生成Certificate Authority（CA），现在想生成Intermediate Certificate。在我当前的工作流程中，CA证书作为X509Certificate2对象返回，我将其传递以生成中间证书。从那里我想阅读PrivateKey，但是这样做很麻烦。

对于生成CA（CACertificateDetails是用于存储要传递的字符串的简单类）：

public static X509Certificate2 GenerateCA(CACertificateDetails details)
{
    // generate a random number
    var random = GetSecureRandom();

    // init the certificate generator
    X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();

    // serial number
    certificateGenerator.SetSerialNumber(SerialNumber(random));

    // set issuer and subject name
    var subjectDN = new X509Name(details.SubjectName);
    var issuerDN = new X509Name(details.IssuerName);
    certificateGenerator.SetIssuerDN(issuerDN);
    certificateGenerator.SetSubjectDN(subjectDN);

    // validation time
    var notBefore = DateTime.UtcNow.Date;
    var notAfter = notBefore.AddYears(details.ValidYears);
    certificateGenerator.SetNotBefore(notBefore);
    certificateGenerator.SetNotAfter(notAfter);

    // subject public Key
    AsymmetricCipherKeyPair subjectKeyPair;
    KeyGenerationParameters keyGenerationParameters = new KeyGenerationParameters(random, details.KeyStrength);
    RsaKeyPairGenerator keyPairGenerator = new RsaKeyPairGenerator();
    keyPairGenerator.Init(keyGenerationParameters);
    subjectKeyPair = keyPairGenerator.GenerateKeyPair();

    certificateGenerator.SetPublicKey(subjectKeyPair.Public);

    // set the hash algorithm
    AsymmetricCipherKeyPair issuerKeyPair = subjectKeyPair;
    ISignatureFactory signatureFactory = new Asn1SignatureFactory(PkcsObjectIdentifiers.Sha512WithRsaEncryption.ToString(), issuerKeyPair.Private, random);

    // generate the certificate
    var certificate = certificateGenerator.Generate(signatureFactory);
    var x509Certificate = new X509Certificate2(certificate.GetEncoded());

    PrivateKeyInfo info = PrivateKeyInfoFactory.CreatePrivateKeyInfo(subjectKeyPair.Private);
    Asn1Sequence seq = (Asn1Sequence)Asn1Object.FromByteArray(info.ParsePrivateKey().GetDerEncoded());
    if (seq.Count != 9)
    {
        throw new PemException("malformed sequence in RSA private key");
    }

    RsaPrivateKeyStructure rsa = RsaPrivateKeyStructure.GetInstance(seq);
    RsaPrivateCrtKeyParameters rsaparams = new RsaPrivateCrtKeyParameters(
        rsa.Modulus, rsa.PublicExponent, rsa.PrivateExponent, rsa.Prime1, rsa.Prime2, rsa.Exponent1, rsa.Exponent2, rsa.Coefficient);

    var convertedRsa = DotNetUtilities.ToRSA(rsaparams);
    var x509CertificateRet = x509Certificate.CopyWithPrivateKey(convertedRsa);
    x509CertificateRet.FriendlyName = details.FriendlyName;

    return x509CertificateRet;
}

生成中间证书的方法如下（刚生成的CA现在作为对象传递）：

public static X509Certificate2 GenerateCertificate(CertificateDetails details, X509Certificate2 issuer)
{
    // generate a random number
    var random = GetSecureRandom();

    // init the certificate generator
    X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();

    // serial number
    certificateGenerator.SetSerialNumber(SerialNumber(random));

    // set issuer and subject name
    var issuerDN = new X509Name(issuer.Issuer);
    certificateGenerator.SetIssuerDN(issuerDN);

    var distinguishedNames = DistinguishedName(details);
    var nameOids = new ArrayList(distinguishedNames.Select(x => x.Item1).ToArray());
    var nameValues = new ArrayList(distinguishedNames.Select(x => x.Item2).ToArray());
    var subjectDN = new X509Name(nameOids, nameValues);
    certificateGenerator.SetSubjectDN(subjectDN);

    // authority key identifier
    var authorityKeyIdentifier = new AuthorityKeyIdentifierStructure(DotNetUtilities.FromX509Certificate(issuer));
    certificateGenerator.AddExtension(X509Extensions.AuthorityKeyIdentifier.Id, false, authorityKeyIdentifier);

    // Basic Constraints - certificate is allowed to be used as intermediate.
    certificateGenerator.AddExtension(X509Extensions.BasicConstraints.Id, true, new BasicConstraints(details.IsIntermediateCertificate));

    // key usage
    if (!details.IsIntermediateCertificate)
    {
        certificateGenerator.AddExtension(X509Extensions.KeyUsage, true, new KeyUsage(KeyUsage.DigitalSignature | KeyUsage.DataEncipherment | KeyUsage.KeyAgreement));
        certificateGenerator.AddExtension(X509Extensions.ExtendedKeyUsage, true, new ExtendedKeyUsage(new[] { KeyPurposeID.IdKPServerAuth, KeyPurposeID.IdKPServerAuth }));
    }
    else
    {
        certificateGenerator.AddExtension(X509Extensions.KeyUsage, true, new KeyUsage(KeyUsage.DigitalSignature | KeyUsage.DataEncipherment | KeyUsage.KeyAgreement | KeyUsage.KeyCertSign));
        certificateGenerator.AddExtension(X509Extensions.ExtendedKeyUsage, true, new ExtendedKeyUsage(KeyPurposeID.AnyExtendedKeyUsage));
    }

    // validation time
    var notBefore = DateTime.UtcNow.Date;
    var notAfter = notBefore.AddYears(details.ValidYears);
    certificateGenerator.SetNotBefore(notBefore);
    certificateGenerator.SetNotAfter(notAfter);

    // subject public Key
    AsymmetricCipherKeyPair subjectKeyPair;
    KeyGenerationParameters keyGenerationParameters = new KeyGenerationParameters(random, details.KeyStrength);
    RsaKeyPairGenerator keyPairGenerator = new RsaKeyPairGenerator();
    keyPairGenerator.Init(keyGenerationParameters);
    subjectKeyPair = keyPairGenerator.GenerateKeyPair();

    certificateGenerator.SetPublicKey(subjectKeyPair.Public);

    // set the hash algorithm
    var issuerPrivateKey = TransformRSAPrivateKey(issuer.PrivateKey);
    ISignatureFactory signatureFactory = new Asn1SignatureFactory("SHA3-512withRSA", issuerPrivateKey, random);

    // generate the certificate
    var certificate = certificateGenerator.Generate(signatureFactory);

    PrivateKeyInfo info = PrivateKeyInfoFactory.CreatePrivateKeyInfo(subjectKeyPair.Private);
    var x509Certificate = new X509Certificate2(certificate.GetEncoded());

    Asn1Sequence seq = (Asn1Sequence)Asn1Object.FromByteArray(info.ParsePrivateKey().GetDerEncoded());
    if (seq.Count != 9)
    {
        throw new PemException("Malformed sequence in RSA private key");
    }

    RsaPrivateKeyStructure rsa = RsaPrivateKeyStructure.GetInstance(seq);
    RsaPrivateCrtKeyParameters rsaparams = new RsaPrivateCrtKeyParameters(
        rsa.Modulus, rsa.PublicExponent, rsa.PrivateExponent, rsa.Prime1, rsa.Prime2, rsa.Exponent1, rsa.Exponent2, rsa.Coefficient);

    x509Certificate.PrivateKey = DotNetUtilities.ToRSA(rsaparams);
    x509Certificate.FriendlyName = details.FriendlyName;

    return x509Certificate;
}

我现在在TransformRSAPrivateKey行的函数prov.ExportParameters(true)上失败了，可能是因为没有找到私钥数据，由于我用x509Certificate.CopyWithPrivateKey(convertedRsa)在CA生成。

private static AsymmetricKeyParameter TransformRSAPrivateKey(AsymmetricAlgorithm privateKey)
{
    RSACryptoServiceProvider prov = privateKey as RSACryptoServiceProvider;
    RSAParameters parameters = prov.ExportParameters(true);

    return new RsaPrivateCrtKeyParameters(
        new BigInteger(1, parameters.Modulus),
        new BigInteger(1, parameters.Exponent),
        new BigInteger(1, parameters.D),
        new BigInteger(1, parameters.P),
        new BigInteger(1, parameters.Q),
        new BigInteger(1, parameters.DP),
        new BigInteger(1, parameters.DQ),
        new BigInteger(1, parameters.InverseQ));
}

如何继续使用CA生成（并签名）我的Intermediate Certificate？我不想传递AsymmetricKeyParameter，如在stackoverflow上的多个示例中所示。在某些时候，我可能想将CA保存到磁盘上，并在另一时间读取它，以生成具有相同CA的证书。那时，我将没有CA生成工作流，因此也就没有AsymmetricKeyParameter对象。

Answer 1

好吧，问题出在以下几行：

// set the hash algorithm
var issuerPrivateKey = TransformRSAPrivateKey(issuer.PrivateKey);
ISignatureFactory signatureFactory = new Asn1SignatureFactory("SHA3-512withRSA", issuerPrivateKey, random);

可以像原始帖子一样将X509Certificate2颁发者证书传递给GenerateCertificate函数。诀窍是使用X509KeyStorageFlags.Exportable之类的标志X509Certificate2(certificatePath, password, X509KeyStorageFlags.PersistKeySet | X509KeyStorageFlags.Exportable);加载该证书。

我进一步将代码更改为

// set the hash algorithm
var issuerPrivateKey = DotNetUtilities.GetKeyPair(issuerCA.PrivateKey).Private;
ISignatureFactory signatureFactory = new Asn1SignatureFactory(PkcsObjectIdentifiers.Sha512WithRsaEncryption.ToString(), issuerPrivateKey, random);

C＃从自签名的根CA生成中间证书

1 个答案: