Error setting X509Certificate2 PrivateKey

Question

I am migrating a .NetFramework 4.6.1 library to a .NetCore 2.2. But i am unable to set x509certificate.PrivateKey as shown below.

I have read that may be due to the

Answer 1

The provided solution did not help me, so I'll be leaving this solution here hoping it will help the next person having this problem.

Using CertBuilder().ConvertBouncyCert it's possible to convert a BouncyCastle X509Certificate to a X509Certificate2 with the public/private key embedded.

X509Certificate2 _x509certificate2 = new CertBuilder().ConvertBouncyCert(_bouncyCertificate, subjectKeyPair);

And the full example i'm using it in (based on the answer provided here: Bouncy Castle's X509V3CertificateGenerator.SetSignatureAlgorithm marked obsolete. What do I do?).

        public static X509Certificate2 CreateSelfSignedCertificateBasedOnCertificateAuthorityPrivateKey(string ipAddress, string issuerName, AsymmetricKeyParameter issuerPrivKey)
    {
        const int keyStrength = 4096;

        // Generating Random Numbers            
        CryptoApiRandomGenerator randomGenerator = new CryptoApiRandomGenerator();
        SecureRandom random = new SecureRandom(randomGenerator);
        ISignatureFactory signatureFactory = new Asn1SignatureFactory("SHA512WITHRSA", issuerPrivKey, random);
        // The Certificate Generator
        X509V3CertificateGenerator certificateGenerator = new X509V3CertificateGenerator();
        certificateGenerator.AddExtension(X509Extensions.ExtendedKeyUsage, true, new ExtendedKeyUsage((new List() { new DerObjectIdentifier("1.3.6.1.5.5.7.3.1"), new DerObjectIdentifier("1.3.6.1.5.5.7.3.2") })));

        // Serial Number
        BigInteger serialNumber = BigIntegers.CreateRandomInRange(BigInteger.One, BigInteger.ValueOf(Int64.MaxValue), random);
        certificateGenerator.SetSerialNumber(serialNumber);

        // Issuer and Subject Name
        X509Name subjectDN = new X509Name("CN=" + ipAddress);
        X509Name issuerDN = new X509Name(issuerName);
        certificateGenerator.SetIssuerDN(issuerDN);
        certificateGenerator.SetSubjectDN(subjectDN);

        // Valid For
        DateTime notBefore = DateTime.UtcNow.Date;
        DateTime notAfter = notBefore.AddYears(2);

        certificateGenerator.SetNotBefore(notBefore);
        certificateGenerator.SetNotAfter(notAfter);

        // Subject Public Key
        AsymmetricCipherKeyPair subjectKeyPair;
        var keyGenerationParameters = new KeyGenerationParameters(random, keyStrength);
        var keyPairGenerator = new RsaKeyPairGenerator();
        keyPairGenerator.Init(keyGenerationParameters);
        subjectKeyPair = keyPairGenerator.GenerateKeyPair();

        certificateGenerator.SetPublicKey(subjectKeyPair.Public);

        GeneralNames subjectAltName = new GeneralNames(new GeneralName(GeneralName.IPAddress, ipAddress));
        certificateGenerator.AddExtension(X509Extensions.SubjectAlternativeName, false, subjectAltName);

        // self sign certificate
        Org.BouncyCastle.X509.X509Certificate certificate = certificateGenerator.Generate(signatureFactory);

        X509Certificate2 certificate2 = new CertBuilder().ConvertBouncyCert(certificate, subjectKeyPair);
        return certificate2;
    }

Used nuget packages:

• Portable.BouncyCastle by Oren Novotny version 1.8.5
• CryptLink.CertBuilder by Jermy Peterson version 1.1.0