Exemple #1
0
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb".
            //
            private static unsafe CERT_ID EncodeRecipientId(CmsRecipient recipient, SafeCertContextHandle hCertContext, CERT_CONTEXT *pCertContext, CERT_INFO *pCertInfo, HeapBlockRetainer hb)
            {
                CERT_ID recipientId        = default(CERT_ID);
                SubjectIdentifierType type = recipient.RecipientIdentifierType;

                switch (type)
                {
                case SubjectIdentifierType.IssuerAndSerialNumber:
                {
                    recipientId.dwIdChoice = CertIdChoice.CERT_ID_ISSUER_SERIAL_NUMBER;
                    recipientId.u.IssuerSerialNumber.Issuer       = pCertInfo->Issuer;
                    recipientId.u.IssuerSerialNumber.SerialNumber = pCertInfo->SerialNumber;
                    break;
                }

                case SubjectIdentifierType.SubjectKeyIdentifier:
                {
                    byte[] ski  = hCertContext.GetSubjectKeyIdentifer();
                    IntPtr pSki = hb.AllocBytes(ski);

                    recipientId.dwIdChoice     = CertIdChoice.CERT_ID_KEY_IDENTIFIER;
                    recipientId.u.KeyId.cbData = (uint)(ski.Length);
                    recipientId.u.KeyId.pbData = pSki;
                    break;
                }

                default:
                    // The public contract for CmsRecipient guarantees that SubjectKeyIdentifier and IssuerAndSerialNumber are the only two possibilities.
                    Debug.Fail($"Unexpected SubjectIdentifierType: {type}");
                    throw new NotSupportedException(SR.Format(SR.Cryptography_Cms_Invalid_Subject_Identifier_Type, type));
                }

                return(recipientId);
            }
Exemple #2
0
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb".
            //
            private static unsafe CMSG_ENVELOPED_ENCODE_INFO *CreateCmsEnvelopedEncodeInfo(CmsRecipientCollection recipients, AlgorithmIdentifier contentEncryptionAlgorithm, X509Certificate2Collection originatorCerts, CryptographicAttributeObjectCollection unprotectedAttributes, HeapBlockRetainer hb)
            {
                CMSG_ENVELOPED_ENCODE_INFO *pEnvelopedEncodeInfo = (CMSG_ENVELOPED_ENCODE_INFO *)(hb.Alloc(sizeof(CMSG_ENVELOPED_ENCODE_INFO)));

                pEnvelopedEncodeInfo->cbSize     = sizeof(CMSG_ENVELOPED_ENCODE_INFO);
                pEnvelopedEncodeInfo->hCryptProv = IntPtr.Zero;

                string algorithmOidValue = contentEncryptionAlgorithm.Oid.Value;

                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.pszObjId = hb.AllocAsciiString(algorithmOidValue);

                // Desktop compat: Though it seems like we could copy over the contents of contentEncryptionAlgorithm.Parameters, that property is for retrieving information from decoded Cms's only, and it
                // massages the raw data so it wouldn't be usable here anyway. To hammer home that fact, the EncryptedCms constructer rather rudely forces contentEncryptionAlgorithm.Parameters to be the empty array.
                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.Parameters.cbData = 0;
                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.Parameters.pbData = IntPtr.Zero;

                pEnvelopedEncodeInfo->pvEncryptionAuxInfo = GenerateEncryptionAuxInfoIfNeeded(contentEncryptionAlgorithm, hb);

                int numRecipients = recipients.Count;

                pEnvelopedEncodeInfo->cRecipients   = numRecipients;
                pEnvelopedEncodeInfo->rgpRecipients = IntPtr.Zero;

                CMSG_RECIPIENT_ENCODE_INFO *rgCmsRecipients = (CMSG_RECIPIENT_ENCODE_INFO *)(hb.Alloc(numRecipients, sizeof(CMSG_RECIPIENT_ENCODE_INFO)));

                for (int index = 0; index < numRecipients; index++)
                {
                    rgCmsRecipients[index] = EncodeRecipientInfo(recipients[index], contentEncryptionAlgorithm, hb);
                }
                pEnvelopedEncodeInfo->rgCmsRecipients = rgCmsRecipients;

                int numCertificates = originatorCerts.Count;

                pEnvelopedEncodeInfo->cCertEncoded  = numCertificates;
                pEnvelopedEncodeInfo->rgCertEncoded = null;
                if (numCertificates != 0)
                {
                    DATA_BLOB *pCertEncoded = (DATA_BLOB *)(hb.Alloc(numCertificates, sizeof(DATA_BLOB)));
                    for (int i = 0; i < numCertificates; i++)
                    {
                        byte[] certEncoded = originatorCerts[i].Export(X509ContentType.Cert);
                        pCertEncoded[i].cbData = (uint)(certEncoded.Length);
                        pCertEncoded[i].pbData = hb.AllocBytes(certEncoded);
                    }
                    pEnvelopedEncodeInfo->rgCertEncoded = pCertEncoded;
                }

                pEnvelopedEncodeInfo->cCrlEncoded  = 0;
                pEnvelopedEncodeInfo->rgCrlEncoded = null;

                pEnvelopedEncodeInfo->cAttrCertEncoded  = 0;
                pEnvelopedEncodeInfo->rgAttrCertEncoded = null;

                int numUnprotectedAttributes = unprotectedAttributes.Count;

                pEnvelopedEncodeInfo->cUnprotectedAttr  = numUnprotectedAttributes;
                pEnvelopedEncodeInfo->rgUnprotectedAttr = null;
                if (numUnprotectedAttributes != 0)
                {
                    CRYPT_ATTRIBUTE *pCryptAttribute = (CRYPT_ATTRIBUTE *)(hb.Alloc(numUnprotectedAttributes, sizeof(CRYPT_ATTRIBUTE)));
                    for (int i = 0; i < numUnprotectedAttributes; i++)
                    {
                        CryptographicAttributeObject attribute = unprotectedAttributes[i];
                        pCryptAttribute[i].pszObjId = hb.AllocAsciiString(attribute.Oid.Value);
                        AsnEncodedDataCollection values = attribute.Values;
                        int numValues = values.Count;
                        pCryptAttribute[i].cValue = numValues;
                        DATA_BLOB *pValues = (DATA_BLOB *)(hb.Alloc(numValues, sizeof(DATA_BLOB)));
                        for (int j = 0; j < numValues; j++)
                        {
                            byte[] rawData = values[j].RawData;
                            pValues[j].cbData = (uint)(rawData.Length);
                            pValues[j].pbData = hb.AllocBytes(rawData);
                        }
                        pCryptAttribute[i].rgValue = pValues;
                    }
                    pEnvelopedEncodeInfo->rgUnprotectedAttr = pCryptAttribute;
                }

                return(pEnvelopedEncodeInfo);
            }
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb".
            //
            private static unsafe CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *EncodeKeyTransRecipientInfo(CmsRecipient recipient, HeapBlockRetainer hb)
            {
                // "recipient" is a deep-cloned CmsRecipient object whose lifetime this class controls. Because of this, we can pull out the CERT_CONTEXT* and CERT_INFO* pointers
                // and embed pointers to them in the memory block we return. Yes, this code is scary.
                //
                // (The use of SafeCertContextHandle here is about using a consistent pattern to get the CERT_CONTEXT (rather than the ugly (CERT_CONTEXT*)(recipient.Certificate.Handle) pattern.)
                // It's not about keeping the context alive.)
                using (SafeCertContextHandle hCertContext = recipient.Certificate.CreateCertContextHandle())
                {
                    CERT_CONTEXT *pCertContext = hCertContext.DangerousGetCertContext();
                    CERT_INFO *   pCertInfo    = pCertContext->pCertInfo;

                    CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *pEncodeInfo = (CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *)(hb.Alloc(sizeof(CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO)));

                    pEncodeInfo->cbSize = sizeof(CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO);

                    if (recipient.RSAEncryptionPadding is null)
                    {
                        CRYPT_ALGORITHM_IDENTIFIER algId = pCertInfo->SubjectPublicKeyInfo.Algorithm;
                        pEncodeInfo->KeyEncryptionAlgorithm = algId;
                    }
                    else if (recipient.RSAEncryptionPadding == RSAEncryptionPadding.Pkcs1)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.Rsa);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaPkcsParameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaPkcsParameters);
                    }
                    else if (recipient.RSAEncryptionPadding == RSAEncryptionPadding.OaepSHA1)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha1Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha1Parameters);
                    }
                    else if (recipient.RSAEncryptionPadding == RSAEncryptionPadding.OaepSHA256)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha256Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha256Parameters);
                    }
                    else if (recipient.RSAEncryptionPadding == RSAEncryptionPadding.OaepSHA384)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha384Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha384Parameters);
                    }
                    else if (recipient.RSAEncryptionPadding == RSAEncryptionPadding.OaepSHA512)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha512Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha512Parameters);
                    }
                    else
                    {
                        throw ErrorCode.CRYPT_E_UNKNOWN_ALGO.ToCryptographicException();
                    }

                    pEncodeInfo->pvKeyEncryptionAuxInfo = IntPtr.Zero;
                    pEncodeInfo->hCryptProv             = IntPtr.Zero;

                    pEncodeInfo->RecipientPublicKey = pCertInfo->SubjectPublicKeyInfo.PublicKey;

                    pEncodeInfo->RecipientId = EncodeRecipientId(recipient, hCertContext, pCertContext, pCertInfo, hb);

                    return(pEncodeInfo);
                }
            }
Exemple #4
0
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb".
            //
            private static unsafe CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *EncodeKeyTransRecipientInfo(CmsRecipient recipient, HeapBlockRetainer hb)
            {
                // "recipient" is a deep-cloned CmsRecipient object whose lifetime this class controls. Because of this, we can pull out the CERT_CONTEXT* and CERT_INFO* pointers
                // and embed pointers to them in the memory block we return. Yes, this code is scary.
                //
                // (The use of SafeCertContextHandle here is about using a consistent pattern to get the CERT_CONTEXT (rather than the ugly (CERT_CONTEXT*)(recipient.Certificate.Handle) pattern.)
                // It's not about keeping the context alive.)
                using (SafeCertContextHandle hCertContext = recipient.Certificate.CreateCertContextHandle())
                {
                    CERT_CONTEXT *pCertContext = hCertContext.DangerousGetCertContext();
                    CERT_INFO *   pCertInfo    = pCertContext->pCertInfo;

                    CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *pEncodeInfo = (CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO *)(hb.Alloc(sizeof(CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO)));

                    pEncodeInfo->cbSize = sizeof(CMSG_KEY_TRANS_RECIPIENT_ENCODE_INFO);

                    RSAEncryptionPadding padding = recipient.RSAEncryptionPadding;

                    if (padding is null)
                    {
                        if (recipient.Certificate.GetKeyAlgorithm() == Oids.RsaOaep)
                        {
                            byte[] parameters = recipient.Certificate.GetKeyAlgorithmParameters();

                            if (parameters == null || parameters.Length == 0)
                            {
                                padding = RSAEncryptionPadding.OaepSHA1;
                            }
                            else if (!PkcsHelpers.TryGetRsaOaepEncryptionPadding(parameters, out padding, out _))
                            {
                                throw ErrorCode.CRYPT_E_UNKNOWN_ALGO.ToCryptographicException();
                            }
                        }
                        else
                        {
                            // gost falls in here
                            padding = RSAEncryptionPadding.Pkcs1;
                        }
                    }

                    if (padding == RSAEncryptionPadding.Pkcs1)
                    {
                        // begin: gost
                        switch (recipient.Certificate.GetKeyAlgorithm())
                        {
                        case Oids.Gost3410:
                        case Oids.Gost3410_2012_256:
                        case Oids.Gost3410_2012_512:
                        {
                            // copy from cert info explicitly
                            pEncodeInfo->KeyEncryptionAlgorithm.pszObjId = hb.AllocAsciiString(recipient.Certificate.GetKeyAlgorithm());

                            // uint, копируем
                            pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = pCertInfo->SubjectPublicKeyInfo.Algorithm.Parameters.cbData;

                            // копируем из памяти и записываем
                            var pbDataBytes = new byte[pCertInfo->SubjectPublicKeyInfo.Algorithm.Parameters.cbData];
                            Marshal.Copy(pCertInfo->SubjectPublicKeyInfo.Algorithm.Parameters.pbData, pbDataBytes, 0, pbDataBytes.Length);
                            pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(pbDataBytes);
                            break;
                        }

                        default:
                        {
                            // end: gost
                            pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.Rsa);
                            pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaPkcsParameters.Length;
                            pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaPkcsParameters);
                            break;
                        }
                        }
                    }
                    else if (padding == RSAEncryptionPadding.OaepSHA1)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha1Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha1Parameters);
                    }
                    else if (padding == RSAEncryptionPadding.OaepSHA256)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha256Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha256Parameters);
                    }
                    else if (padding == RSAEncryptionPadding.OaepSHA384)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha384Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha384Parameters);
                    }
                    else if (padding == RSAEncryptionPadding.OaepSHA512)
                    {
                        pEncodeInfo->KeyEncryptionAlgorithm.pszObjId          = hb.AllocAsciiString(Oids.RsaOaep);
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.cbData = (uint)s_rsaOaepSha512Parameters.Length;
                        pEncodeInfo->KeyEncryptionAlgorithm.Parameters.pbData = hb.AllocBytes(s_rsaOaepSha512Parameters);
                    }
                    else
                    {
                        throw ErrorCode.CRYPT_E_UNKNOWN_ALGO.ToCryptographicException();
                    }

                    pEncodeInfo->pvKeyEncryptionAuxInfo = IntPtr.Zero;
                    pEncodeInfo->hCryptProv             = IntPtr.Zero;

                    pEncodeInfo->RecipientPublicKey = pCertInfo->SubjectPublicKeyInfo.PublicKey;

                    pEncodeInfo->RecipientId = EncodeRecipientId(recipient, hCertContext, pCertContext, pCertInfo, hb);

                    return(pEncodeInfo);
                }
            }
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb". 
            //
            private static unsafe CMSG_ENVELOPED_ENCODE_INFO* CreateCmsEnvelopedEncodeInfo(CmsRecipientCollection recipients, AlgorithmIdentifier contentEncryptionAlgorithm, X509Certificate2Collection originatorCerts, CryptographicAttributeObjectCollection unprotectedAttributes, HeapBlockRetainer hb)
            {
                CMSG_ENVELOPED_ENCODE_INFO* pEnvelopedEncodeInfo = (CMSG_ENVELOPED_ENCODE_INFO*)(hb.Alloc(sizeof(CMSG_ENVELOPED_ENCODE_INFO)));
                pEnvelopedEncodeInfo->cbSize = sizeof(CMSG_ENVELOPED_ENCODE_INFO);
                pEnvelopedEncodeInfo->hCryptProv = IntPtr.Zero;

                string algorithmOidValue = contentEncryptionAlgorithm.Oid.Value;
                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.pszObjId = hb.AllocAsciiString(algorithmOidValue);

                // Desktop compat: Though it seems like we could copy over the contents of contentEncryptionAlgorithm.Parameters, that property is for retrieving information from decoded Cms's only, and it 
                // massages the raw data so it wouldn't be usable here anyway. To hammer home that fact, the EncryptedCms constructer rather rudely forces contentEncryptionAlgorithm.Parameters to be the empty array.
                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.Parameters.cbData = 0;
                pEnvelopedEncodeInfo->ContentEncryptionAlgorithm.Parameters.pbData = IntPtr.Zero;

                pEnvelopedEncodeInfo->pvEncryptionAuxInfo = GenerateEncryptionAuxInfoIfNeeded(contentEncryptionAlgorithm, hb);

                int numRecipients = recipients.Count;
                pEnvelopedEncodeInfo->cRecipients = numRecipients;
                pEnvelopedEncodeInfo->rgpRecipients = IntPtr.Zero;

                CMSG_RECIPIENT_ENCODE_INFO* rgCmsRecipients = (CMSG_RECIPIENT_ENCODE_INFO*)(hb.Alloc(numRecipients, sizeof(CMSG_RECIPIENT_ENCODE_INFO)));
                for (int index = 0; index < numRecipients; index++)
                {
                    rgCmsRecipients[index] = EncodeRecipientInfo(recipients[index], contentEncryptionAlgorithm, hb);
                }
                pEnvelopedEncodeInfo->rgCmsRecipients = rgCmsRecipients;

                int numCertificates = originatorCerts.Count;
                pEnvelopedEncodeInfo->cCertEncoded = numCertificates;
                pEnvelopedEncodeInfo->rgCertEncoded = null;
                if (numCertificates != 0)
                {
                    DATA_BLOB* pCertEncoded = (DATA_BLOB*)(hb.Alloc(numCertificates, sizeof(DATA_BLOB)));
                    for (int i = 0; i < numCertificates; i++)
                    {
                        byte[] certEncoded = originatorCerts[i].Export(X509ContentType.Cert);
                        pCertEncoded[i].cbData = (uint)(certEncoded.Length);
                        pCertEncoded[i].pbData = hb.AllocBytes(certEncoded);
                    }
                    pEnvelopedEncodeInfo->rgCertEncoded = pCertEncoded;
                }

                pEnvelopedEncodeInfo->cCrlEncoded = 0;
                pEnvelopedEncodeInfo->rgCrlEncoded = null;

                pEnvelopedEncodeInfo->cAttrCertEncoded = 0;
                pEnvelopedEncodeInfo->rgAttrCertEncoded = null;

                int numUnprotectedAttributes = unprotectedAttributes.Count;
                pEnvelopedEncodeInfo->cUnprotectedAttr = numUnprotectedAttributes;
                pEnvelopedEncodeInfo->rgUnprotectedAttr = null;
                if (numUnprotectedAttributes != 0)
                {
                    CRYPT_ATTRIBUTE* pCryptAttribute = (CRYPT_ATTRIBUTE*)(hb.Alloc(numUnprotectedAttributes, sizeof(CRYPT_ATTRIBUTE)));
                    for (int i = 0; i < numUnprotectedAttributes; i++)
                    {
                        CryptographicAttributeObject attribute = unprotectedAttributes[i];
                        pCryptAttribute[i].pszObjId = hb.AllocAsciiString(attribute.Oid.Value);
                        AsnEncodedDataCollection values = attribute.Values;
                        int numValues = values.Count;
                        pCryptAttribute[i].cValue = numValues;
                        DATA_BLOB* pValues = (DATA_BLOB*)(hb.Alloc(numValues, sizeof(DATA_BLOB)));
                        for (int j = 0; j < numValues; j++)
                        {
                            byte[] rawData = values[j].RawData;
                            pValues[j].cbData = (uint)(rawData.Length);
                            pValues[j].pbData = hb.AllocBytes(rawData);
                        }
                        pCryptAttribute[i].rgValue = pValues;
                    }
                    pEnvelopedEncodeInfo->rgUnprotectedAttr = pCryptAttribute;
                }

                return pEnvelopedEncodeInfo;
            }
            //
            // This returns an allocated native memory block. Its lifetime (and that of any allocated subblocks it may point to) is that of "hb". 
            //
            private static unsafe CERT_ID EncodeRecipientId(CmsRecipient recipient, SafeCertContextHandle hCertContext, CERT_CONTEXT* pCertContext, CERT_INFO* pCertInfo, HeapBlockRetainer hb)
            {
                CERT_ID recipientId = default(CERT_ID);
                SubjectIdentifierType type = recipient.RecipientIdentifierType;
                switch (type)
                {
                    case SubjectIdentifierType.IssuerAndSerialNumber:
                        {
                            recipientId.dwIdChoice = CertIdChoice.CERT_ID_ISSUER_SERIAL_NUMBER;
                            recipientId.u.IssuerSerialNumber.Issuer = pCertInfo->Issuer;
                            recipientId.u.IssuerSerialNumber.SerialNumber = pCertInfo->SerialNumber;
                            break;
                        }

                    case SubjectIdentifierType.SubjectKeyIdentifier:
                        {
                            byte[] ski = hCertContext.GetSubjectKeyIdentifer();
                            IntPtr pSki = hb.AllocBytes(ski);

                            recipientId.dwIdChoice = CertIdChoice.CERT_ID_KEY_IDENTIFIER;
                            recipientId.u.KeyId.cbData = (uint)(ski.Length);
                            recipientId.u.KeyId.pbData = pSki;
                            break;
                        }

                    default:
                        // The public contract for CmsRecipient guarantees that SubjectKeyIdentifier and IssuerAndSerialNumber are the only two possibilities.
                        Debug.Fail($"Unexpected SubjectIdentifierType: {type}");
                        throw new NotSupportedException(SR.Format(SR.Cryptography_Cms_Invalid_Subject_Identifier_Type, type));
                }

                return recipientId;
            }