how to create a completely new x509Certificate2 in .net?

Question

I google it from web, find many samples to generate a new x509Certificate2 from a file in .net, but there is no one sample to show how to generate a completely new x509Certi

Answer 1

Here's a code you can use:

    static X509Certificate2 GenerateCertificate(string certName)
    {
        var keypairgen = new RsaKeyPairGenerator();
        keypairgen.Init(new KeyGenerationParameters(new SecureRandom(new CryptoApiRandomGenerator()), 1024));

        var keypair = keypairgen.GenerateKeyPair();

        var gen = new X509V3CertificateGenerator();

        var CN = new X509Name("CN=" + certName);
        var SN = BigInteger.ProbablePrime(120, new Random());

        gen.SetSerialNumber(SN);
        gen.SetSubjectDN(CN);
        gen.SetIssuerDN(CN);
        gen.SetNotAfter(DateTime.MaxValue);
        gen.SetNotBefore(DateTime.Now.Subtract(new TimeSpan(7, 0, 0, 0)));
        gen.SetSignatureAlgorithm("MD5WithRSA");
        gen.SetPublicKey(keypair.Public);           

        var newCert = gen.Generate(keypair.Private);

        return new X509Certificate2(DotNetUtilities.ToX509Certificate((Org.BouncyCastle.X509.X509Certificate)newCert));
    }

for this to work, don't forget to add reference to BouncyCastle library