1 files changed, 123 insertions, 0 deletions
diff --git a/crypto/src/cms/EnvelopedDataHelper.cs b/crypto/src/cms/EnvelopedDataHelper.cs
new file mode 100644
index 000000000..89ec79691
--- /dev/null
+++ b/crypto/src/cms/EnvelopedDataHelper.cs
@@ -0,0 +1,123 @@
+using System.Collections;
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Nist;
+using Org.BouncyCastle.Asn1.Oiw;
+using Org.BouncyCastle.Asn1.Pkcs;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Crypto.Digests;
+using Org.BouncyCastle.Crypto.Engines;
+using Org.BouncyCastle.Crypto.Operators;
+using Org.BouncyCastle.Crypto.Parameters;
+using Org.BouncyCastle.Crypto.Utilities;
+using Org.BouncyCastle.Security;
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Cms
+{
+    public class EnvelopedDataHelper
+    {
+        private static readonly IDictionary BaseCipherNames = Platform.CreateHashtable();
+        private static readonly IDictionary MacAlgNames = Platform.CreateHashtable();
+
+        private static readonly IDictionary prfs = Platform.CreateHashtable();
+
+
+        public delegate IDigest DigestCreator();
+
+        static EnvelopedDataHelper()
+        {
+            prfs.Add(PkcsObjectIdentifiers.IdHmacWithSha1, new DigestProvider(delegate () { return new Sha1Digest(); }));
+            prfs.Add(PkcsObjectIdentifiers.IdHmacWithSha224, new DigestProvider(delegate () { return new Sha224Digest(); }));
+            prfs.Add(PkcsObjectIdentifiers.IdHmacWithSha256, new DigestProvider(delegate () { return new Sha256Digest(); }));
+            prfs.Add(PkcsObjectIdentifiers.IdHmacWithSha384, new DigestProvider(delegate () { return new Sha384Digest(); }));
+            prfs.Add(PkcsObjectIdentifiers.IdHmacWithSha512, new DigestProvider(delegate () { return new Sha512Digest(); }));
+
+
+            BaseCipherNames.Add(PkcsObjectIdentifiers.DesEde3Cbc, "DESEDE");
+            BaseCipherNames.Add(NistObjectIdentifiers.IdAes128Cbc, "AES");
+            BaseCipherNames.Add(NistObjectIdentifiers.IdAes192Cbc, "AES");
+            BaseCipherNames.Add(NistObjectIdentifiers.IdAes256Cbc, "AES");
+
+            MacAlgNames.Add(PkcsObjectIdentifiers.DesEde3Cbc, "DESEDEMac");
+            MacAlgNames.Add(NistObjectIdentifiers.IdAes128Cbc, "AESMac");
+            MacAlgNames.Add(NistObjectIdentifiers.IdAes192Cbc, "AESMac");
+            MacAlgNames.Add(NistObjectIdentifiers.IdAes256Cbc, "AESMac");
+            MacAlgNames.Add(PkcsObjectIdentifiers.RC2Cbc, "RC2Mac");
+        }
+
+        static IDigest GetPrf(AlgorithmIdentifier algID)
+        {
+            return ((DigestCreator)prfs[algID]).Invoke();
+        }
+
+
+        static IWrapper CreateRFC3211Wrapper(DerObjectIdentifier algorithm)
+
+        {
+            if (NistObjectIdentifiers.IdAes128Cbc.Equals(algorithm)
+        || NistObjectIdentifiers.IdAes192Cbc.Equals(algorithm)
+        || NistObjectIdentifiers.IdAes256Cbc.Equals(algorithm))
+            {
+                return new Rfc3211WrapEngine(new AesEngine());
+            }
+            else if (PkcsObjectIdentifiers.DesEde3Cbc.Equals(algorithm))
+            {
+                return new Rfc3211WrapEngine(new DesEdeEngine());
+            }
+            else if (OiwObjectIdentifiers.DesCbc.Equals(algorithm))
+            {
+                return new Rfc3211WrapEngine(new DesEngine());
+            }
+            else if (PkcsObjectIdentifiers.RC2Cbc.Equals(algorithm))
+            {
+                return new Rfc3211WrapEngine(new RC2Engine());
+            }
+            else
+            {
+                throw new CmsException("cannot recognise wrapper: " + algorithm);
+            }
+        }
+
+
+
+       public static object CreateContentCipher(bool forEncryption, ICipherParameters encKey,
+            AlgorithmIdentifier encryptionAlgID)
+
+        {
+            return CipherFactory.CreateContentCipher(forEncryption, encKey, encryptionAlgID);
+        }
+
+
+        public AlgorithmIdentifier GenerateEncryptionAlgID(DerObjectIdentifier encryptionOID, KeyParameter encKey, SecureRandom random)
+
+        {
+            return AlgorithmIdentifierFactory.GenerateEncryptionAlgID(encryptionOID, encKey.GetKey().Length * 8, random);
+        }
+
+       public  CipherKeyGenerator CreateKeyGenerator(DerObjectIdentifier algorithm, SecureRandom random)
+
+        {
+            return CipherKeyGeneratorFactory.CreateKeyGenerator(algorithm, random);
+        }
+
+
+    }
+
+    // This exists because we can't directly put a delegate in a map as it is
+    // not an object.
+    internal class DigestProvider
+    {
+        private readonly EnvelopedDataHelper.DigestCreator creator;
+
+        public DigestProvider(EnvelopedDataHelper.DigestCreator creator)
+        {
+            this.creator = creator;
+        }
+
+        public IDigest Create()
+        {
+            return creator.Invoke();
+        }
+    }
+}
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