/// <summary>
/// Lookup and validate certificate against CDP URL inside the certificate.
/// </summary>
/// <param name="cert"></param>
/// <returns></returns>
public CertStatus ValidateCertificateAgainstCRL(System.Security.Cryptography.X509Certificates.X509Certificate2 cert)
{
var urls = ParseCDPUrls(cert);
if (urls == null || urls.Count == 0 || urls.Count > 1)
{
return(CertStatus.Unknown(CertStatus.NoCrl));
}
var crl = LoadCrl(urls[0]);
if (crl.NextUpdate.Value < DateTime.UtcNow)
{
return(CertStatus.Unknown(CertStatus.BadCrl));
}
var serialNumber = new BigInteger(cert.SerialNumber, 16);
var entry = crl.GetRevokedCertificate(serialNumber);
if (entry == null)
{
return(CertStatus.Good);
}
DerEnumerated reasonCode = null;
try
{
reasonCode = DerEnumerated.GetInstance(entry.GetExtensionValue(X509Extensions.ReasonCode));
}
catch
{
return(CertStatus.Unknown(CertStatus.BadRevocationReason));
}
int?revocationReason = null;
if (reasonCode != null)
{
revocationReason = reasonCode.Value.SignValue;
}
else
{
revocationReason = CrlReason.Unspecified;
}
DateTime revocationDate = entry.RevocationDate;
return(CertStatus.Revoked(revocationDate.ToString("o"), revocationReason));
}
/// <summary>
/// Validate a certificate against its AIA OCSP.
/// </summary>
/// <param name="cert"></param>
/// <param name="aia"></param>
/// <returns></returns>
CertStatus Validate(System.Security.Cryptography.X509Certificates.X509Certificate2 cert,
AIA aia)
{
string hash = ComputeSHA1(System.Text.ASCIIEncoding.ASCII.GetBytes(aia.Issuer));
string filePath = IssuerCachedFolder + hash;
//Check if aki is cached
if (!IsIssuerCached(aia.Issuer))
{
Download(aia.Issuer, filePath);
if (!IsIssuerCached(aia.Issuer))
{
return(CertStatus.Unknown(CertStatus.BadIssuer));
}
}
var issuerTemp = new System.Security.Cryptography.X509Certificates.X509Certificate2(filePath);
var certParser = new Org.BouncyCastle.X509.X509CertificateParser();
var issuer = certParser.ReadCertificate(issuerTemp.RawData);
var cert2Validate = certParser.ReadCertificate(cert.RawData);
var id = new Org.BouncyCastle.Ocsp.CertificateID(
Org.BouncyCastle.Ocsp.CertificateID.HashSha1,
issuer,
cert2Validate.SerialNumber);
byte[] reqEnc = GenerateOCSPRequest(id, cert2Validate);
byte[] resp = GetOCSPResponse(aia.Ocsp, reqEnc);
//Extract the response
OcspResp ocspResponse = new OcspResp(resp);
BasicOcspResp basicOCSPResponse =
(BasicOcspResp)ocspResponse.GetResponseObject();
SingleResp singResp = basicOCSPResponse.Responses[0];
//Validate ID
var expectedId = singResp.GetCertID();
if (!expectedId.SerialNumber.Equals(id.SerialNumber))
{
return(CertStatus.Unknown(CertStatus.BadSerial));
}
if (!Org.BouncyCastle.Utilities.Arrays.AreEqual(expectedId.GetIssuerNameHash(), id.GetIssuerNameHash()))
{
return(CertStatus.Unknown(CertStatus.IssuerNotMatch));
}
//Extract Status
var certificateStatus = singResp.GetCertStatus();
if (certificateStatus == null)
{
return(CertStatus.Good);
}
if (certificateStatus is Org.BouncyCastle.Ocsp.RevokedStatus)
{
int revocationReason = ((Org.BouncyCastle.Ocsp.RevokedStatus)certificateStatus).RevocationReason;
var revocationDate = ((Org.BouncyCastle.Ocsp.RevokedStatus)certificateStatus).RevocationTime;
return(CertStatus.Revoked(revocationDate.ToString("o"), revocationReason));
}
if (certificateStatus is Org.BouncyCastle.Ocsp.UnknownStatus)
{
return(CertStatus.Unknown());
}
return(CertStatus.Unknown());
}