1 files changed, 69 insertions, 0 deletions
diff --git a/crypto/src/cms/PasswordRecipientInfoGenerator.cs b/crypto/src/cms/PasswordRecipientInfoGenerator.cs
new file mode 100644
index 000000000..0a0b27b53
--- /dev/null
+++ b/crypto/src/cms/PasswordRecipientInfoGenerator.cs
@@ -0,0 +1,69 @@
+using System;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Cms
+{
+	internal class PasswordRecipientInfoGenerator : RecipientInfoGenerator
+	{
+		private static readonly CmsEnvelopedHelper Helper = CmsEnvelopedHelper.Instance;
+
+		private AlgorithmIdentifier	keyDerivationAlgorithm;
+		private KeyParameter		keyEncryptionKey;
+		// TODO Can get this from keyEncryptionKey?		
+		private string				keyEncryptionKeyOID;
+
+		internal PasswordRecipientInfoGenerator()
+		{
+		}
+
+		internal AlgorithmIdentifier KeyDerivationAlgorithm
+		{
+			set { this.keyDerivationAlgorithm = value; }
+		}
+
+		internal KeyParameter KeyEncryptionKey
+		{
+			set { this.keyEncryptionKey = value; }
+		}
+
+		internal string KeyEncryptionKeyOID
+		{
+			set { this.keyEncryptionKeyOID = value; }
+		}
+
+		public RecipientInfo Generate(KeyParameter contentEncryptionKey, SecureRandom random)
+		{
+			byte[] keyBytes = contentEncryptionKey.GetKey();
+
+			string rfc3211WrapperName = Helper.GetRfc3211WrapperName(keyEncryptionKeyOID);
+			IWrapper keyWrapper = Helper.CreateWrapper(rfc3211WrapperName);
+
+			// Note: In Java build, the IV is automatically generated in JCE layer
+			int ivLength = rfc3211WrapperName.StartsWith("DESEDE") ? 8 : 16;
+			byte[] iv = new byte[ivLength];
+			random.NextBytes(iv);
+
+			ICipherParameters parameters = new ParametersWithIV(keyEncryptionKey, iv);
+			keyWrapper.Init(true, new ParametersWithRandom(parameters, random));
+        	Asn1OctetString encryptedKey = new DerOctetString(
+				keyWrapper.Wrap(keyBytes, 0, keyBytes.Length));
+
+			DerSequence seq = new DerSequence(
+				new DerObjectIdentifier(keyEncryptionKeyOID),
+				new DerOctetString(iv));
+
+			AlgorithmIdentifier keyEncryptionAlgorithm = new AlgorithmIdentifier(
+				PkcsObjectIdentifiers.IdAlgPwriKek, seq);
+
+			return new RecipientInfo(new PasswordRecipientInfo(
+				keyDerivationAlgorithm, keyEncryptionAlgorithm, encryptedKey));
+		}
+	}
+}