src/block/block_cipher.h

Go to the documentation of this file.

/*
* Block Cipher Base Class
* (C) 1999-2009 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/

#ifndef BOTAN_BLOCK_CIPHER_H__
#define BOTAN_BLOCK_CIPHER_H__

#include <botan/sym_algo.h>

namespace Botan {

/**
* This class represents a block cipher object.
*/
class BOTAN_DLL BlockCipher : public SymmetricAlgorithm
   {
   public:
      /**
      * BlockCipher constructor
      * @param block_size the size of blocks this cipher processes
      * @param key_min the minimum key size
      * @param key_max the maximum key size
      * @param key_mod the modulo restriction on the key size
      */
      BlockCipher(u32bit block_size,
                  u32bit key_min,
                  u32bit key_max = 0,
                  u32bit key_mod = 1) :
         SymmetricAlgorithm(key_min, key_max, key_mod),
         BLOCK_SIZE(block_size) {}

      virtual ~BlockCipher() {}

      /**
      * The block size of this algorithm.
      */
      const u32bit BLOCK_SIZE;

      /**
      * @return native parallelism of this cipher in blocks
      */
      virtual u32bit parallelism() const { return 1; }

      /**
      * @return prefererred parallelism of this cipher in bytes
      */
      u32bit parallel_bytes() const
         {
         return parallelism() * BLOCK_SIZE * BOTAN_BLOCK_CIPHER_PAR_MULT;
         }

      /**
      * Encrypt a block.
      * @param in The plaintext block to be encrypted as a byte array.
      * Must be of length BLOCK_SIZE.
      * @param out The byte array designated to hold the encrypted block.
      * Must be of length BLOCK_SIZE.
      */
      void encrypt(const byte in[], byte out[]) const
         { encrypt_n(in, out, 1); }

      /**
      * Decrypt a block.
      * @param in The ciphertext block to be decypted as a byte array.
      * Must be of length BLOCK_SIZE.
      * @param out The byte array designated to hold the decrypted block.
      * Must be of length BLOCK_SIZE.
      */
      void decrypt(const byte in[], byte out[]) const
         { decrypt_n(in, out, 1); }

      /**
      * Encrypt a block.
      * @param block the plaintext block to be encrypted
      * Must be of length BLOCK_SIZE. Will hold the result when the function
      * has finished.
      */
      void encrypt(byte block[]) const { encrypt_n(block, block, 1); }

      /**
      * Decrypt a block.
      * @param block the ciphertext block to be decrypted
      * Must be of length BLOCK_SIZE. Will hold the result when the function
      * has finished.
      */
      void decrypt(byte block[]) const { decrypt_n(block, block, 1); }

      /**
      * Encrypt one or more blocks
      * @param in the input buffer (multiple of BLOCK_SIZE)
      * @param out the output buffer (same size as in)
      * @param blocks the number of blocks to process
      */
      virtual void encrypt_n(const byte in[], byte out[],
                             u32bit blocks) const = 0;

      /**
      * Decrypt one or more blocks
      * @param in the input buffer (multiple of BLOCK_SIZE)
      * @param out the output buffer (same size as in)
      * @param blocks the number of blocks to process
      */
      virtual void decrypt_n(const byte in[], byte out[],
                             u32bit blocks) const = 0;

      /**
      * Get a new object representing the same algorithm as *this
      */
      virtual BlockCipher* clone() const = 0;

      /**
      * Zeroize internal state
      */
      virtual void clear() = 0;
   };

}

#endif

---