private static X509Certificate GenerateCertificate(Org.BouncyCastle.Security.SecureRandom random,
string subjectName,
AsymmetricCipherKeyPair subjectKeyPair,
BigInteger subjectSerialNumber,
string[] subjectAlternativeNames,
string issuerName,
AsymmetricCipherKeyPair issuerKeyPair,
BigInteger issuerSerialNumber,
bool isCertificateAuthority,
KeyPurposeID[] usages,
int expiresIn)
{
var certificateGenerator = new X509V3CertificateGenerator();
certificateGenerator.SetSerialNumber(subjectSerialNumber);
// Set the signature algorithm. This is used to generate the thumbprint which is then signed
// with the issuer's private key. We'll use SHA-256, which is (currently) considered fairly strong.
const string signatureAlgorithm = "SHA256WithRSA";
certificateGenerator.SetSignatureAlgorithm(signatureAlgorithm);
var issuerDN = new X509Name(issuerName);
certificateGenerator.SetIssuerDN(issuerDN);
// Note: The subject can be omitted if you specify a subject alternative name (SAN).
var subjectDN = new X509Name(subjectName);
certificateGenerator.SetSubjectDN(subjectDN);
// Our certificate needs valid from/to values.
var notBefore = DateTime.UtcNow.Date;
var notAfter = notBefore.AddYears(expiresIn);
certificateGenerator.SetNotBefore(notBefore);
certificateGenerator.SetNotAfter(notAfter);
// The subject's public key goes in the certificate.
certificateGenerator.SetPublicKey(subjectKeyPair.Public);
certificateGenerator.AddAuthorityKeyIdentifier(issuerDN, issuerKeyPair, issuerSerialNumber);
certificateGenerator.AddSubjectKeyIdentifier(subjectKeyPair);
certificateGenerator.AddBasicConstraints(isCertificateAuthority);
if (usages != null && usages.Any())
{
certificateGenerator.AddExtendedKeyUsage(usages);
}
if (subjectAlternativeNames != null && subjectAlternativeNames.Any())
{
certificateGenerator.AddSubjectAlternativeNames(subjectAlternativeNames);
}
// The certificate is signed with the issuer's private key.
var certificate = certificateGenerator.Generate(issuerKeyPair.Private, random);
return(certificate);
}
