sapphire.h

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/******************************************************************************
 *
 * sapphire.h - the Saphire II stream cipher class
 *
 * $Id: sapphire.h 3786 2020-08-30 11:35:14Z scribe $
 * 
 * Copyright 1999-2013 CrossWire Bible Society (http://www.crosswire.org)
 *  CrossWire Bible Society
 *  P. O. Box 2528
 *  Tempe, AZ  85280-2528
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation version 2.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 */

/******************************************************************************
 *
 * Original license notice & credits:
 * Dedicated to the Public Domain the author and inventor
 * (Michael Paul Johnson).  This code comes with no warranty.
 * Use it at your own risk.
 * Ported from the Pascal implementation of the Sapphire Stream
 * Cipher 9 December 1994.
 * Added hash-specific functions 27 December 1994.
 * Made index variable initialization key-dependent,
 * made the output function more resistant to cryptanalysis,
 * and renamed to Sapphire II Stream Cipher 2 January 1995.
 *
 * unsigned char is assumed to be 8 bits.  If it is not, the
 * results of assignments need to be reduced to 8 bits with
 * & 0xFF or % 0x100, whichever is faster.
 */

#ifndef NULL
#define NULL 0
#endif

#include <defs.h>

SWORD_NAMESPACE_START

class Sapphire {

private:
    // These variables comprise the state of the state machine.
    unsigned char cards[256];   // A permutation of 0-255.
    unsigned char rotor,        // Index that rotates smoothly
        ratchet,        // Index that moves erratically
        avalanche,      // Index heavily data dependent
        last_plain,     // Last plain text byte
        last_cipher;        // Last cipher text byte

    // This function is used by initialize(), which is called by the
    // constructor.
    unsigned char keyrand(int limit, unsigned char *user_key,
        unsigned char keysize, unsigned char *rsum,
        unsigned *keypos);
public:
    Sapphire(unsigned char *key = NULL, // Calls initialize if a real
        unsigned char keysize = 0); // key is provided.  If none
                        // is provided, call initialize
                        // before encrypt or decrypt.

    ~Sapphire();                // Destroy cipher state information.

    void initialize(unsigned char *key, // User key is used to set
        unsigned char keysize);     // up state information.
    void hash_init(void);           // Set up default hash.
    unsigned char encrypt(unsigned char b = 0); // Encrypt byte
                            // or get a random byte.
    unsigned char decrypt(unsigned char b); // Decrypt byte.
    void hash_final(unsigned char *hash,    // Copy hash value to hash
        unsigned char hashlength = 20); // Hash length (16-32)
    void burn(void);            // Destroy cipher state information.
};


SWORD_NAMESPACE_END