namespace NBitcoin.BouncyCastle.Crypto
{
    /// <remarks>Base interface for a symmetric key block cipher.</remarks>
    internal interface IBlockCipher
    {
        /// <summary>The name of the algorithm this cipher implements.</summary>
        string AlgorithmName
        {
            get;
        }

        /// <summary>Initialise the cipher.</summary>
        /// <param name="forEncryption">Initialise for encryption if true, for decryption if false.</param>
        /// <param name="parameters">The key or other data required by the cipher.</param>
        void Init(bool forEncryption, ICipherParameters parameters);

        /// <returns>The block size for this cipher, in bytes.</returns>
        int GetBlockSize();

        /// <summary>Indicates whether this cipher can handle partial blocks.</summary>
        bool IsPartialBlockOkay
        {
            get;
        }

        /// <summary>Process a block.</summary>
        /// <param name="inBuf">The input buffer.</param>
        /// <param name="inOff">The offset into <paramref>inBuf</paramref> that the input block begins.</param>
        /// <param name="outBuf">The output buffer.</param>
        /// <param name="outOff">The offset into <paramref>outBuf</paramref> to write the output block.</param>
        /// <exception cref="DataLengthException">If input block is wrong size, or outBuf too small.</exception>
        /// <returns>The number of bytes processed and produced.</returns>
        int ProcessBlock(byte[] inBuf, int inOff, byte[] outBuf, int outOff);

        /// <summary>
        /// Reset the cipher to the same state as it was after the last init (if there was one).
        /// </summary>
        void Reset();
    }
}
