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public Verify ( |
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| publicKey | ||
| return | bool | |
/**
* Checks if an OCSP response is genuine
* @param ocspResp the OCSP response
* @param responderCert the responder certificate
* @return true if the OCSP response verifies against the responder certificate
*/
public bool IsSignatureValid(BasicOcspResp ocspResp, X509Certificate responderCert) {
try {
return ocspResp.Verify(responderCert.GetPublicKey());
} catch (OcspException) {
return false;
}
}
/**
* Verifies an OCSP response against a KeyStore.
* @param ocsp the OCSP response
* @param keystore the <CODE>KeyStore</CODE>
* @param provider the provider or <CODE>null</CODE> to use the BouncyCastle provider
* @return <CODE>true</CODE> is a certificate was found
*/
public static bool VerifyOcspCertificates(BasicOcspResp ocsp, ICollection<X509Certificate> keystore)
{
try {
foreach (X509Certificate certStoreX509 in keystore) {
try {
if (ocsp.Verify(certStoreX509.GetPublicKey()))
return true;
}
catch {
}
}
}
catch {
}
return false;
}
//2. The signature on the response is valid;
private void ValidateResponseSignature(BasicOcspResp or, Org.BouncyCastle.Crypto.AsymmetricKeyParameter asymmetricKeyParameter)
{
if (!or.Verify(asymmetricKeyParameter))
{
throw new Exception("Invalid OCSP signature");
}
}
/// <summary>
/// Validates the cert with the provided ocsp responses.
/// </summary>
/// <param name="certificate">The cert to validate</param>
/// <param name="issuer">The issuer of the cert to validate</param>
/// <param name="validationTime">The time on which the cert was needed to validated</param>
/// <param name="ocspResponses">The list of ocsp responses to use</param>
/// <returns>The OCSP response that was used, <c>null</c> if none was found</returns>
/// <exception cref="RevocationException{T}">When the certificate was revoked on the provided time</exception>
/// <exception cref="RevocationUnknownException">When the certificate (or the OCSP) can't be validated</exception>
public static BCAO.BasicOcspResponse Verify(this X509Certificate2 certificate, X509Certificate2 issuer, DateTime validationTime, IList <BCAO.BasicOcspResponse> ocspResponses)
{
DateTime minTime = validationTime - ClockSkewness;
DateTime maxTime = validationTime + ClockSkewness;
BCX.X509Certificate certificateBC = DotNetUtilities.FromX509Certificate(certificate);
BCX.X509Certificate issuerBC = DotNetUtilities.FromX509Certificate(issuer);
ValueWithRef <BCO.SingleResp, ValueWithRef <BCO.BasicOcspResp, BCAO.BasicOcspResponse> > singleOcspRespLeaf = ocspResponses
.Select((rsp) => new ValueWithRef <BCO.BasicOcspResp, BCAO.BasicOcspResponse>(new BCO.BasicOcspResp(rsp), rsp)) //convert, but keep the original
.SelectMany((r) => r.Value.Responses.Select(sr => new ValueWithRef <BCO.SingleResp, ValueWithRef <BCO.BasicOcspResp, BCAO.BasicOcspResponse> >(sr, r))) //get the single respononses, but keep the parent
.Where((sr) => sr.Value.GetCertID().SerialNumber.Equals(certificateBC.SerialNumber) && sr.Value.GetCertID().MatchesIssuer(issuerBC)) //is it for this cert?
.Where((sr) => sr.Value.ThisUpdate >= minTime || (sr.Value.NextUpdate != null && sr.Value.NextUpdate.Value >= minTime)) //was it issued on time?
.OrderByDescending((sr) => sr.Value.ThisUpdate) //newest first
.FirstOrDefault();
if (singleOcspRespLeaf == null)
{
return(null);
}
BCO.SingleResp singleOcspResp = singleOcspRespLeaf.Value;
BCO.BasicOcspResp basicOcspResp = singleOcspRespLeaf.Reference.Value;
BCAO.BasicOcspResponse basicOcspResponse = singleOcspRespLeaf.Reference.Reference;
//get the signer name
BCAX.X509Name responderName = basicOcspResp.ResponderId.ToAsn1Object().Name;
if (responderName == null)
{
trace.TraceEvent(TraceEventType.Error, 0, "OCSP response for {0} does not have a ResponderID", certificate.Subject);
throw new RevocationUnknownException("OCSP response for {0} does not have a ResponderID");
}
//Get the signer certificate
var selector = new BCS.X509CertStoreSelector();
selector.Subject = responderName;
BCX.X509Certificate ocspSignerBc = (BCX.X509Certificate)basicOcspResp
.GetCertificates("Collection").GetMatches(selector)
.Cast <BCX.X509Certificate>().FirstOrDefault();
if (ocspSignerBc == null)
{
throw new RevocationUnknownException("The OCSP is signed by a unknown certificate");
}
//verify the response signature
if (!basicOcspResp.Verify(ocspSignerBc.GetPublicKey()))
{
throw new RevocationUnknownException("The OCSP has an invalid signature");
}
//OCSP must be issued by same issuer an the certificate that it validates.
try
{
if (!ocspSignerBc.IssuerDN.Equals(issuerBC.SubjectDN))
{
throw new ApplicationException();
}
ocspSignerBc.Verify(issuerBC.GetPublicKey());
}
catch (Exception e)
{
throw new RevocationUnknownException("The OCSP signer was not issued by the proper CA", e);
}
//verify if the OCSP signer certificate is stil valid
if (!ocspSignerBc.IsValid(basicOcspResp.ProducedAt))
{
throw new RevocationUnknownException("The OCSP signer was not valid at the time the ocsp was issued");
}
//check if the signer may issue OCSP
IList ocspSignerExtKeyUsage = ocspSignerBc.GetExtendedKeyUsage();
if (!ocspSignerExtKeyUsage.Contains("1.3.6.1.5.5.7.3.9"))
{
throw new RevocationUnknownException("The OCSP is signed by a certificate that isn't allowed to sign OCSP");
}
//finally, check if the certificate is revoked or not
var revokedStatus = (BCO.RevokedStatus)singleOcspResp.GetCertStatus();
if (revokedStatus != null)
{
trace.TraceEvent(TraceEventType.Verbose, 0, "OCSP response for {0} indicates that the certificate is revoked on {1}", certificate.Subject, revokedStatus.RevocationTime);
if (maxTime >= revokedStatus.RevocationTime)
{
throw new RevocationException <BCAO.BasicOcspResponse>(basicOcspResponse, "The certificate was revoked on " + revokedStatus.RevocationTime.ToString("o"));
}
}
return(basicOcspResponse);
}
private void ValidarResponseSignature(BasicOcspResp in_OcspResp, Org.BouncyCastle.Crypto.AsymmetricKeyParameter in_PublicKey)
{
if (!in_OcspResp.Verify(in_PublicKey))
{
throw new Exception("Firma OCSP Invalida");
}
}
private static void CheckBasicOcspResp(CertID id, BasicOcspResp basicResp, OcesCertificate ocspCertificate, Ca ca)
{
DateTime nowInGmt = DateTime.Now.ToUniversalTime();
/* check condition:
The certificate identified in a received response corresponds to
that which was identified in the corresponding request;
*/
SingleResp[] responses = basicResp.Responses;
if (responses.Length != 1)
{
throw new OcspException("unexpected number of responses received");
}
if (!id.SerialNumber.Value.Equals(responses[0].GetCertID().SerialNumber))
{
throw new OcspException("Serial number mismatch problem");
}
/* check condition
The signature on the response is valid;
*/
try
{
ChainVerifier.VerifyTrust(ocspCertificate.ExportCertificate(), ca);
}
catch(ChainVerificationException e)
{
throw new OcspException("OCSP response certificate chain is invalid", e);
}
/* check the signature on the ocsp response */
var ocspBcCertificate =
new X509CertificateParser().ReadCertificate(ocspCertificate.ExportCertificate().RawData);
if (!basicResp.Verify(ocspBcCertificate.GetPublicKey()))
{
throw new OcspException("signature validation failed for ocsp response");
}
if (!CanSignOcspResponses(ocspBcCertificate))
{
throw new OcspException("ocsp signing certificate has not been cleared for ocsp response signing");
}
/* check expiry of the signing certificate */
if (ocspCertificate.ValidityStatus() != CertificateStatus.Valid)
{
throw new OcspException("OCSP certificate expired or not yet valid");
}
/* check condition
The time at which the status being indicated is known to be
correct (thisUpdate) is sufficiently recent.
*/
SingleResp response = responses[0];
var diff = response.ThisUpdate - nowInGmt;
if (diff > new TimeSpan(0, 1, 0))
{
throw new OcspException("OCSP response signature is from the future. Timestamp of thisUpdate field: "
+ response.ThisUpdate);
}
if (response.NextUpdate != null && response.NextUpdate.Value < nowInGmt)
{
throw new OcspException("OCSP response is no longer valid");
}
}
static void CheckValidityOfResponse(CertID id, BasicOcspResp responseObject, Ca ca)
{
var inputStream = new MemoryStream(responseObject.GetEncoded());
var asn1Sequence = (Asn1Sequence)new Asn1InputStream(inputStream).ReadObject();
var response = BasicOcspResponse.GetInstance(asn1Sequence);
var ocspChain = CreateOcspCertificateChain(ca);
if(ocspChain.Length == 0)
{
throw new OcspException("OCSP certificate chain is invalid");
}
var ocesOcspCertificate = OcesCertificateFactory.Instance.Generate(CompleteOcspChain(response, ocspChain));
CheckBasicOcspResp(id, responseObject, ocesOcspCertificate, ca);
var signingCertificate = new X509CertificateParser().ReadCertificate(response.Certs[0].GetEncoded());
var issuingCertificate = new X509CertificateParser().ReadCertificate(ocspChain[0].GetRawCertData());
signingCertificate.Verify(issuingCertificate.GetPublicKey());
if (!responseObject.Verify(signingCertificate.GetPublicKey()))
{
throw new OcspException("Signature is invalid");
}
}
