1 files changed, 61 insertions, 0 deletions
diff --git a/crypto/src/tls/crypto/TlsCipher.cs b/crypto/src/tls/crypto/TlsCipher.cs
new file mode 100644
index 000000000..4c2147bf7
--- /dev/null
+++ b/crypto/src/tls/crypto/TlsCipher.cs
@@ -0,0 +1,61 @@
+using System;
+using System.IO;
+
+namespace Org.BouncyCastle.Tls.Crypto
+{
+    /// <summary>Base interface for a TLS bulk cipher.</summary>
+    public interface TlsCipher
+    {
+        /// <summary>Return the maximum input size for a ciphertext given a maximum output size for the plaintext of
+        /// plaintextLimit bytes.</summary>
+        /// <param name="plaintextLimit">the maximum output size for the plaintext.</param>
+        /// <returns>the maximum input size of the ciphertext for plaintextlimit bytes of output.</returns>
+        int GetCiphertextDecodeLimit(int plaintextLimit);
+
+        /// <summary>Return the maximum output size for a ciphertext given an actual input plaintext size of
+        /// plaintextLength bytes and a maximum input plaintext size of plaintextLimit bytes.</summary>
+        /// <param name="plaintextLength">the actual input size for the plaintext.</param>
+        /// <param name="plaintextLimit">the maximum input size for the plaintext.</param>
+        /// <returns>the maximum output size of the ciphertext for plaintextlimit bytes of input.</returns>
+        int GetCiphertextEncodeLimit(int plaintextLength, int plaintextLimit);
+
+        /// <summary>Return the maximum size for the plaintext given ciphertextlimit bytes of ciphertext.</summary>
+        /// <param name="ciphertextLimit">the maximum number of bytes of ciphertext.</param>
+        /// <returns>the maximum size of the plaintext for ciphertextlimit bytes of input.</returns>
+        int GetPlaintextLimit(int ciphertextLimit);
+
+        /// <summary>Encode the passed in plaintext using the current bulk cipher.</summary>
+        /// <param name="seqNo">sequence number of the message represented by plaintext.</param>
+        /// <param name="contentType">content type of the message represented by plaintext.</param>
+        /// <param name="recordVersion"><see cref="ProtocolVersion"/> used for the record.</param>
+        /// <param name="headerAllocation">extra bytes to allocate at start of returned byte array.</param>
+        /// <param name="plaintext">array holding input plaintext to the cipher.</param>
+        /// <param name="offset">offset into input array the plaintext starts at.</param>
+        /// <param name="len">length of the plaintext in the array.</param>
+        /// <returns>A <see cref="TlsEncodeResult"/> containing the result of encoding (after 'headerAllocation' unused
+        /// bytes).</returns>
+        /// <exception cref="IOException"/>
+        TlsEncodeResult EncodePlaintext(long seqNo, short contentType, ProtocolVersion recordVersion,
+            int headerAllocation, byte[] plaintext, int offset, int len);
+
+        /// <summary>Decode the passed in ciphertext using the current bulk cipher.</summary>
+        /// <param name="seqNo">sequence number of the message represented by ciphertext.</param>
+        /// <param name="recordType">content type used in the record for this message.</param>
+        /// <param name="recordVersion"><see cref="ProtocolVersion"/> used for the record.</param>
+        /// <param name="ciphertext">array holding input ciphertext to the cipher.</param>
+        /// <param name="offset">offset into input array the ciphertext starts at.</param>
+        /// <param name="len">length of the ciphertext in the array.</param>
+        /// <returns>A <see cref="TlsDecodeResult"/> containing the result of decoding.</returns>
+        /// <exception cref="IOException"/>
+        TlsDecodeResult DecodeCiphertext(long seqNo, short recordType, ProtocolVersion recordVersion,
+            byte[] ciphertext, int offset, int len);
+
+        /// <exception cref="IOException"/>
+        void RekeyDecoder();
+
+        /// <exception cref="IOException"/>
+        void RekeyEncoder();
+
+        bool UsesOpaqueRecordType { get; }
+    }
+}