1 files changed, 113 insertions, 0 deletions
diff --git a/Crypto/src/cms/KeyTransRecipientInformation.cs b/Crypto/src/cms/KeyTransRecipientInformation.cs
new file mode 100644
index 000000000..24121cb2c
--- /dev/null
+++ b/Crypto/src/cms/KeyTransRecipientInformation.cs
@@ -0,0 +1,113 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Asn1Pkcs = Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.X509;
+
+namespace Org.BouncyCastle.Cms
+{
+ /**
+ * the KeyTransRecipientInformation class for a recipient who has been sent a secret
+ * key encrypted using their public key that needs to be used to
+ * extract the message.
+ */
+ public class KeyTransRecipientInformation
+ : RecipientInformation
+ {
+ private KeyTransRecipientInfo info;
+
+ internal KeyTransRecipientInformation(
+ KeyTransRecipientInfo info,
+ CmsSecureReadable secureReadable)
+ : base(info.KeyEncryptionAlgorithm, secureReadable)
+ {
+ this.info = info;
+ this.rid = new RecipientID();
+
+ RecipientIdentifier r = info.RecipientIdentifier;
+
+ try
+ {
+ if (r.IsTagged)
+ {
+ Asn1OctetString octs = Asn1OctetString.GetInstance(r.ID);
+
+ rid.SubjectKeyIdentifier = octs.GetOctets();
+ }
+ else
+ {
+ IssuerAndSerialNumber iAnds = IssuerAndSerialNumber.GetInstance(r.ID);
+
+ rid.Issuer = iAnds.Name;
+ rid.SerialNumber = iAnds.SerialNumber.Value;
+ }
+ }
+ catch (IOException)
+ {
+ throw new ArgumentException("invalid rid in KeyTransRecipientInformation");
+ }
+ }
+
+ private string GetExchangeEncryptionAlgorithmName(
+ DerObjectIdentifier oid)
+ {
+ if (Asn1Pkcs.PkcsObjectIdentifiers.RsaEncryption.Equals(oid))
+ {
+ return "RSA//PKCS1Padding";
+ }
+
+ return oid.Id;
+ }
+
+ internal KeyParameter UnwrapKey(ICipherParameters key)
+ {
+ byte[] encryptedKey = info.EncryptedKey.GetOctets();
+ string keyExchangeAlgorithm = GetExchangeEncryptionAlgorithmName(keyEncAlg.ObjectID);
+
+ try
+ {
+ IWrapper keyWrapper = WrapperUtilities.GetWrapper(keyExchangeAlgorithm);
+ keyWrapper.Init(false, key);
+
+ // FIXME Support for MAC algorithm parameters similar to cipher parameters
+ return ParameterUtilities.CreateKeyParameter(
+ GetContentAlgorithmName(), keyWrapper.Unwrap(encryptedKey, 0, encryptedKey.Length));
+ }
+ catch (SecurityUtilityException e)
+ {
+ throw new CmsException("couldn't create cipher.", e);
+ }
+ catch (InvalidKeyException e)
+ {
+ throw new CmsException("key invalid in message.", e);
+ }
+// catch (IllegalBlockSizeException e)
+ catch (DataLengthException e)
+ {
+ throw new CmsException("illegal blocksize in message.", e);
+ }
+// catch (BadPaddingException e)
+ catch (InvalidCipherTextException e)
+ {
+ throw new CmsException("bad padding in message.", e);
+ }
+ }
+
+ /**
+ * decrypt the content and return it as a byte array.
+ */
+ public override CmsTypedStream GetContentStream(
+ ICipherParameters key)
+ {
+ KeyParameter sKey = UnwrapKey(key);
+
+ return GetContentFromSessionKey(sKey);
+ }
+ }
+}
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