Crypto++  5.6.3
Free C++ class library of cryptographic schemes
blowfish.cpp
1 // blowfish.cpp - written and placed in the public domain by Wei Dai
2 
3 #include "pch.h"
4 #include "blowfish.h"
5 #include "misc.h"
6 
7 NAMESPACE_BEGIN(CryptoPP)
8 
9 void Blowfish::Base::UncheckedSetKey(const byte *key_string, unsigned int keylength, const NameValuePairs &)
10 {
11  AssertValidKeyLength(keylength);
12 
13  unsigned i, j=0, k;
14  word32 data, dspace[2] = {0, 0};
15 
16  memcpy(pbox, p_init, sizeof(p_init));
17  memcpy(sbox, s_init, sizeof(s_init));
18 
19  // Xor key string into encryption key vector
20  for (i=0 ; i<ROUNDS+2 ; ++i)
21  {
22  data = 0 ;
23  for (k=0 ; k<4 ; ++k )
24  data = (data << 8) | key_string[j++ % keylength];
25  pbox[i] ^= data;
26  }
27 
28  crypt_block(dspace, pbox);
29 
30  for (i=0; i<ROUNDS; i+=2)
31  crypt_block(pbox+i, pbox+i+2);
32 
33  crypt_block(pbox+ROUNDS, sbox);
34 
35  for (i=0; i<4*256-2; i+=2)
36  crypt_block(sbox+i, sbox+i+2);
37 
38  if (!IsForwardTransformation())
39  for (i=0; i<(ROUNDS+2)/2; i++)
40  std::swap(pbox[i], pbox[ROUNDS+1-i]);
41 }
42 
43 // this version is only used to make pbox and sbox
44 void Blowfish::Base::crypt_block(const word32 in[2], word32 out[2]) const
45 {
46  word32 left = in[0];
47  word32 right = in[1];
48 
49  const word32 *const s=sbox;
50  const word32 *p=pbox;
51 
52  left ^= p[0];
53 
54  for (unsigned i=0; i<ROUNDS/2; i++)
55  {
56  right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)])
57  ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)])
58  ^ p[2*i+1];
59 
60  left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)])
61  ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)])
62  ^ p[2*i+2];
63  }
64 
65  right ^= p[ROUNDS+1];
66 
67  out[0] = right;
68  out[1] = left;
69 }
70 
71 void Blowfish::Base::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
72 {
74 
75  word32 left, right;
76  Block::Get(inBlock)(left)(right);
77 
78  const word32 *const s=sbox;
79  const word32 *p=pbox;
80 
81  left ^= p[0];
82 
83  for (unsigned i=0; i<ROUNDS/2; i++)
84  {
85  right ^= (((s[GETBYTE(left,3)] + s[256+GETBYTE(left,2)])
86  ^ s[2*256+GETBYTE(left,1)]) + s[3*256+GETBYTE(left,0)])
87  ^ p[2*i+1];
88 
89  left ^= (((s[GETBYTE(right,3)] + s[256+GETBYTE(right,2)])
90  ^ s[2*256+GETBYTE(right,1)]) + s[3*256+GETBYTE(right,0)])
91  ^ p[2*i+2];
92  }
93 
94  right ^= p[ROUNDS+1];
95 
96  Block::Put(xorBlock, outBlock)(right)(left);
97 }
98 
99 NAMESPACE_END
Utility functions for the Crypto++ library.
Classes for the Blowfish block cipher.
Crypto++ library namespace.
Interface for retrieving values given their names.
Definition: cryptlib.h:277