up

Assets/BestHTTP/SecureProtocol/crypto/tls/TlsNullCipher.cs

@@ -0,0 +1,122 @@
+#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR)
+
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Utilities;
+
+namespace Org.BouncyCastle.Crypto.Tls
+{
+    /// <summary>
+    /// A NULL CipherSuite, with optional MAC.
+    /// </summary>
+    public class TlsNullCipher
+        :   TlsCipher
+    {
+        protected readonly TlsContext context;
+
+        protected readonly TlsMac writeMac;
+        protected readonly TlsMac readMac;
+
+        public TlsNullCipher(TlsContext context)
+        {
+            this.context = context;
+            this.writeMac = null;
+            this.readMac = null;
+        }
+
+        /// <exception cref="IOException"></exception>
+        public TlsNullCipher(TlsContext context, IDigest clientWriteDigest, IDigest serverWriteDigest)
+        {
+            if ((clientWriteDigest == null) != (serverWriteDigest == null))
+                throw new TlsFatalAlert(AlertDescription.internal_error);
+
+            this.context = context;
+
+            TlsMac clientWriteMac = null, serverWriteMac = null;
+
+            if (clientWriteDigest != null)
+            {
+                int key_block_size = clientWriteDigest.GetDigestSize()
+                    + serverWriteDigest.GetDigestSize();
+                byte[] key_block = TlsUtilities.CalculateKeyBlock(context, key_block_size);
+
+                int offset = 0;
+
+                clientWriteMac = new TlsMac(context, clientWriteDigest, key_block, offset,
+                    clientWriteDigest.GetDigestSize());
+                offset += clientWriteDigest.GetDigestSize();
+
+                serverWriteMac = new TlsMac(context, serverWriteDigest, key_block, offset,
+                    serverWriteDigest.GetDigestSize());
+                offset += serverWriteDigest.GetDigestSize();
+
+                if (offset != key_block_size)
+                {
+                    throw new TlsFatalAlert(AlertDescription.internal_error);
+                }
+            }
+
+            if (context.IsServer)
+            {
+                writeMac = serverWriteMac;
+                readMac = clientWriteMac;
+            }
+            else
+            {
+                writeMac = clientWriteMac;
+                readMac = serverWriteMac;
+            }
+        }
+
+        public virtual int GetPlaintextLimit(int ciphertextLimit)
+        {
+            int result = ciphertextLimit;
+            if (writeMac != null)
+            {
+                result -= writeMac.Size;
+            }
+            return result;
+        }
+
+        /// <exception cref="IOException"></exception>
+        public virtual byte[] EncodePlaintext(long seqNo, byte type, byte[] plaintext, int offset, int len)
+        {
+            if (writeMac == null)
+            {
+                return Arrays.CopyOfRange(plaintext, offset, offset + len);
+            }
+
+            byte[] mac = writeMac.CalculateMac(seqNo, type, plaintext, offset, len);
+            byte[] ciphertext = new byte[len + mac.Length];
+            Array.Copy(plaintext, offset, ciphertext, 0, len);
+            Array.Copy(mac, 0, ciphertext, len, mac.Length);
+            return ciphertext;
+        }
+
+        /// <exception cref="IOException"></exception>
+        public virtual byte[] DecodeCiphertext(long seqNo, byte type, byte[] ciphertext, int offset, int len)
+        {
+            if (readMac == null)
+            {
+                return Arrays.CopyOfRange(ciphertext, offset, offset + len);
+            }
+
+            int macSize = readMac.Size;
+            if (len < macSize)
+                throw new TlsFatalAlert(AlertDescription.decode_error);
+
+            int macInputLen = len - macSize;
+
+            byte[] receivedMac = Arrays.CopyOfRange(ciphertext, offset + macInputLen, offset + len);
+            byte[] computedMac = readMac.CalculateMac(seqNo, type, ciphertext, offset, macInputLen);
+
+            if (!Arrays.ConstantTimeAreEqual(receivedMac, computedMac))
+                throw new TlsFatalAlert(AlertDescription.bad_record_mac);
+
+            return Arrays.CopyOfRange(ciphertext, offset, offset + macInputLen);
+        }
+    }
+}
+
+#endif