using System; using System.IO; using Org.BouncyCastle.Asn1; using Org.BouncyCastle.Asn1.Ess; using Org.BouncyCastle.Asn1.Nist; using Org.BouncyCastle.Asn1.Oiw; using Org.BouncyCastle.Asn1.Pkcs; using Org.BouncyCastle.Asn1.Tsp; using Org.BouncyCastle.Asn1.X509; using Org.BouncyCastle.Cms; using Org.BouncyCastle.Security; using Org.BouncyCastle.Security.Certificates; using Org.BouncyCastle.Utilities; using Org.BouncyCastle.Utilities.Collections; using Org.BouncyCastle.X509; namespace Org.BouncyCastle.Tsp { public class TimeStampToken { private readonly CmsSignedData tsToken; private readonly SignerInformation tsaSignerInfo; // private readonly DateTime genTime; private readonly TimeStampTokenInfo tstInfo; private readonly CertID certID; public TimeStampToken( Asn1.Cms.ContentInfo contentInfo) : this(new CmsSignedData(contentInfo)) { } public TimeStampToken( CmsSignedData signedData) { this.tsToken = signedData; if (!this.tsToken.SignedContentType.Equals(PkcsObjectIdentifiers.IdCTTstInfo)) { throw new TspValidationException("ContentInfo object not for a time stamp."); } var signers = tsToken.GetSignerInfos().GetSigners(); if (signers.Count != 1) { throw new ArgumentException("Time-stamp token signed by " + signers.Count + " signers, but it must contain just the TSA signature."); } var signerEnum = signers.GetEnumerator(); signerEnum.MoveNext(); tsaSignerInfo = signerEnum.Current; try { CmsProcessable content = tsToken.SignedContent; MemoryStream bOut = new MemoryStream(); content.Write(bOut); this.tstInfo = new TimeStampTokenInfo( TstInfo.GetInstance( Asn1Object.FromByteArray(bOut.ToArray()))); Asn1.Cms.Attribute attr = tsaSignerInfo.SignedAttributes[ PkcsObjectIdentifiers.IdAASigningCertificate]; // if (attr == null) // { // throw new TspValidationException( // "no signing certificate attribute found, time stamp invalid."); // } // // SigningCertificate signCert = SigningCertificate.GetInstance( // attr.AttrValues[0]); // // this.certID = EssCertID.GetInstance(signCert.GetCerts()[0]); if (attr != null) { if (attr.AttrValues[0] is SigningCertificateV2) { SigningCertificateV2 signCert = SigningCertificateV2.GetInstance(attr.AttrValues[0]); this.certID = new CertID(EssCertIDv2.GetInstance(signCert.GetCerts()[0])); } else { SigningCertificate signCert = SigningCertificate.GetInstance(attr.AttrValues[0]); this.certID = new CertID(EssCertID.GetInstance(signCert.GetCerts()[0])); } } else { attr = tsaSignerInfo.SignedAttributes[PkcsObjectIdentifiers.IdAASigningCertificateV2]; if (attr == null) throw new TspValidationException("no signing certificate attribute found, time stamp invalid."); SigningCertificateV2 signCertV2 = SigningCertificateV2.GetInstance(attr.AttrValues[0]); this.certID = new CertID(EssCertIDv2.GetInstance(signCertV2.GetCerts()[0])); } } catch (CmsException e) { throw new TspException(e.Message, e.InnerException); } } public TimeStampTokenInfo TimeStampInfo { get { return tstInfo; } } public SignerID SignerID { get { return tsaSignerInfo.SignerID; } } public Asn1.Cms.AttributeTable SignedAttributes { get { return tsaSignerInfo.SignedAttributes; } } public Asn1.Cms.AttributeTable UnsignedAttributes { get { return tsaSignerInfo.UnsignedAttributes; } } public IStore GetAttributeCertificates() => tsToken.GetAttributeCertificates(); public IStore GetCertificates() => tsToken.GetCertificates(); public IStore GetCrls() => tsToken.GetCrls(); /** * Validate the time stamp token. *

* To be valid the token must be signed by the passed in certificate and * the certificate must be the one referred to by the SigningCertificate * attribute included in the hashed attributes of the token. The * certificate must also have the ExtendedKeyUsageExtension with only * KeyPurposeID.IdKPTimeStamping and have been valid at the time the * timestamp was created. *

*

* A successful call to validate means all the above are true. *

*/ public void Validate( X509Certificate cert) { try { byte[] hash = DigestUtilities.CalculateDigest( certID.GetHashAlgorithmName(), cert.GetEncoded()); if (!Arrays.FixedTimeEquals(certID.GetCertHash(), hash)) throw new TspValidationException("certificate hash does not match certID hash."); if (certID.IssuerSerial != null) { if (!certID.IssuerSerial.Serial.HasValue(cert.SerialNumber)) throw new TspValidationException("certificate serial number does not match certID for signature."); GeneralName[] names = certID.IssuerSerial.Issuer.GetNames(); X509Name principal = PrincipalUtilities.GetIssuerX509Principal(cert); bool found = false; for (int i = 0; i != names.Length; i++) { if (names[i].TagNo == 4 && X509Name.GetInstance(names[i].Name).Equivalent(principal)) { found = true; break; } } if (!found) { throw new TspValidationException("certificate name does not match certID for signature. "); } } TspUtil.ValidateCertificate(cert); cert.CheckValidity(tstInfo.GenTime); if (!tsaSignerInfo.Verify(cert)) { throw new TspValidationException("signature not created by certificate."); } } catch (CmsException e) { if (e.InnerException != null) { throw new TspException(e.Message, e.InnerException); } throw new TspException("CMS exception: " + e, e); } catch (CertificateEncodingException e) { throw new TspException("problem processing certificate: " + e, e); } catch (SecurityUtilityException e) { throw new TspException("cannot find algorithm: " + e.Message, e); } } /** * Return the underlying CmsSignedData object. * * @return the underlying CMS structure. */ public CmsSignedData ToCmsSignedData() { return tsToken; } /** * Return a ASN.1 encoded byte stream representing the encoded object. * * @throws IOException if encoding fails. */ public byte[] GetEncoded() { return tsToken.GetEncoded(Asn1Encodable.Der); } /** * return the ASN.1 encoded representation of this object using the specified encoding. * * @param encoding the ASN.1 encoding format to use ("BER" or "DER"). */ public byte[] GetEncoded(string encoding) { return tsToken.GetEncoded(encoding); } // perhaps this should be done using an interface on the ASN.1 classes... private class CertID { private EssCertID certID; private EssCertIDv2 certIDv2; internal CertID(EssCertID certID) { this.certID = certID; this.certIDv2 = null; } internal CertID(EssCertIDv2 certID) { this.certIDv2 = certID; this.certID = null; } public string GetHashAlgorithmName() { if (certID != null) return "SHA-1"; if (NistObjectIdentifiers.IdSha256.Equals(certIDv2.HashAlgorithm.Algorithm)) return "SHA-256"; return certIDv2.HashAlgorithm.Algorithm.Id; } public AlgorithmIdentifier GetHashAlgorithm() { return (certID != null) ? new AlgorithmIdentifier(OiwObjectIdentifiers.IdSha1) : certIDv2.HashAlgorithm; } public byte[] GetCertHash() { return certID != null ? certID.GetCertHash() : certIDv2.GetCertHash(); } public IssuerSerial IssuerSerial { get { return certID != null ? certID.IssuerSerial : certIDv2.IssuerSerial; } } } } }