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Generated signed X.509 client certificate is invalid (no certificate chain to its CA)
I followed the example at:
But the resulting signed client certificate has the following error when opened in windows:
"This file is invalid for use as the following: Security Certificate"
If I install it anyway and view it with certmgr, the certification path looks OK - I see my self-signed Certificate Authority (which is fine, no problems there) but the client cert has the following status:
"This certificate has an invalid digital signature."
If I call X509Certificate.Verify() it throws the following exception:
"Public key presented not for certificate signature"
Yet I'm using the same exact public key extracted from the Pkcs10CertificationRequest and when I called Verify() on that it's fine.
Any ideas? After days of struggling through this, I've got all the pieces working except this last one - and what's really confusing is that my self-signed CA cert is fine. There's just something going on with the client cert. Here's the entire block of code:
TextReader textReader = new StreamReader("certificaterequest.pkcs10");
PemReader pemReader = new PemReader(textReader);
Pkcs10CertificationRequest certificationRequest = (Pkcs10CertificationRequest)pemReader.ReadObject();
CertificationRequestInfo certificationRequestInfo = certificationRequest.GetCertificationRequestInfo();
SubjectPublicKeyInfo publicKeyInfo = certificationRequestInfo.SubjectPublicKeyInfo;
RsaPublicKeyStructure publicKeyStructure = RsaPublicKeyStructure.GetInstance(publicKeyInfo.GetPublicKey());
RsaKeyParameters publicKey = new RsaKeyParameters(false, publicKeyStructure.Modulus, publicKeyStructure.PublicExponent);
bool certIsOK = certificationRequest.Verify(publicKey);
// public key is OK here...
// get the server certificate
Org.BouncyCastle.X509.X509Certificate serverCertificate = DotNetUtilities.FromX509Certificate(System.Security.Cryptography.X509Certificates.X509Certificate.CreateFromCertFile("servermastercertificate.cer"));
// get the server private key
byte[] privateKeyBytes = File.ReadAllBytes("serverprivate.key");
AsymmetricKeyParameter serverPrivateKey = PrivateKeyFactory.CreateKey(privateKeyBytes);
// generate the client certificate
X509V3CertificateGenerator generator = new X509V3CertificateGenerator();
generator.SetSerialNumber(BigInteger.ProbablePrime(120, new Random()));
generator.SetIssuerDN(serverCertificate.SubjectDN);
generator.SetNotBefore(DateTime.Now);
generator.SetNotAfter(DateTime.Now.AddYears(5));
generator.SetSubjectDN(certificationRequestInfo.Subject);
generator.SetPublicKey(publicKey);
generator.SetSignatureAlgorithm("SHA512withRSA");
generator.AddExtension(X509Extensions.AuthorityKeyIdentifier, false, new AuthorityKeyIdentifierStructure(serverCertificate));
generator.AddExtension(X509Extensions.SubjectKeyIdentifier, false, new SubjectKeyIdentifierStructure(publicKey));
var newClientCert = generator.Generate(serverPrivateKey);
newClientCert.Verify(publicKey); // <-- this blows up
return DotNetUtilities.ToX509Certificate(newClientCert).Export(X509ContentType.Pkcs12, "user password");
I figured this out. If you call X509Certificate.Verify(publicKey) you have to pass the CA's public key, not the client's public key from the Pkcs10CertificationRequest.