include/wvblowfish.h

   1 /* -*- Mode: C++ -*-
   2  * Worldvisions Tunnel Vision Software:
   3  *   Copyright (C) 1997-2002 Net Integration Technologies, Inc.
   4  *
   5  * Blowfish cryptography abstractions.
   6  */
   7 #ifndef __WVBLOWFISH_H
   8 #define __WVBLOWFISH_H
   9
  10 #include "wvencoder.h"
  11 #include "wvencoderstream.h"
  12
  13 struct bf_key_st;
  14
  15 /**
  16  * An encoder implementing the Blowfish encryption method.
  17  *
  18  * Supports reset().
  19  *
  20  */
  21 class WvBlowfishEncoder : public WvEncoder
  22 {
  23 public:
  24     enum Mode {
  25         ECBEncrypt, /*!< Encrypt using ECB mode (avoid) */
  26         ECBDecrypt, /*!< Decrypt using ECB mode (avoid) */
  27         CFBEncrypt, /*!< Encrypt using CFB mode (simulates a stream) */
  28         CFBDecrypt  /*!< Decrypt using CFB mode (simulates a stream) */
  29     };
  30
  31     /**
  32      * Creates a new Blowfish cipher encoder.
  33      *
  34      * "mode" is the encryption mode
  35      * "key" is the initial key
  36      * "keysize" is the initial key size in bytes
  37      */
  38     WvBlowfishEncoder(Mode mode, const void *key, size_t keysize);
  39     virtual ~WvBlowfishEncoder();
  40
  41     /**
  42      * Sets the current Blowfish key and resets the initialization
  43      * vector to all nulls.
  44      *
  45      * "key" is the new key
  46      * "keysize" is the key size in bytes
  47      */
  48     void setkey(const void *key, size_t keysize);
  49
  50     /**
  51      * Sets the current Blowfish initialization vector.
  52      *
  53      * "iv" is the new IV must be 8 bytes
  54      */
  55     void setiv(const void *iv);
  56
  57     /** Return true if mode is encrypting or false if decrypting. */
  58     bool is_encrypting() const {
  59         return (mode == ECBEncrypt || mode == CFBEncrypt);
  60     }
  61
  62 protected:
  63     virtual bool _encode(WvBuf &in, WvBuf &out, bool flush);
  64     virtual bool _reset(); // supported: restores most recently set
  65         // key and initialization vector
  66
  67     Mode mode;
  68     size_t keysize;
  69     unsigned char *key;
  70     struct bf_key_st *bfkey;
  71     unsigned char ivec[8]; // initialization vector
  72     int ivecoff; // current offset into initvec
  73
  74     void preparekey();
  75 };
  76
  77
  78 /**
  79  * A crypto stream implementing Blowfish encryption.
  80  *
  81  * By default, written data is encrypted using
  82  * WvBlowfishEncoder::CFBEncrypt, read data is decrypted using
  83  * WvBlowfishEncoder::CFBDecrypt.
  84  *
  85  * @see WvBlowfishEncoder
  86  */
  87 class WvBlowfishStream : public WvEncoderStream
  88 {
  89 public:
  90     WvBlowfishStream(WvStream *_cloned,
  91         const void *key, size_t _keysize,
  92         WvBlowfishEncoder::Mode readmode = WvBlowfishEncoder::CFBDecrypt,
  93         WvBlowfishEncoder::Mode writemode = WvBlowfishEncoder::CFBEncrypt);
  94     virtual ~WvBlowfishStream() { }
  95 };
  96
  97 #endif // __WVBLOWFISH_H