Botan: src/block/blowfish/blowfish.cpp Source File

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blowfish.cpp
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1 /*
2 * Blowfish
3 * (C) 1999-2011 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7
8 #include <botan/blowfish.h>
9 #include <botan/loadstor.h>
10
11 namespace Botan {
12
13 /*
14 * Blowfish Encryption
15 */
16 void Blowfish::encrypt_n(const byte in[], byte out[], size_t blocks) const
17 {
18 const u32bit* S1 = &S[0];
19 const u32bit* S2 = &S[256];
20 const u32bit* S3 = &S[512];
21 const u32bit* S4 = &S[768];
22
23 for(size_t i = 0; i != blocks; ++i)
24 {
25 u32bit L = load_be<u32bit>(in, 0);
26 u32bit R = load_be<u32bit>(in, 1);
27
28 for(size_t j = 0; j != 16; j += 2)
29 {
30 L ^= P[j];
31 R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
32 S3[get_byte(2, L)]) + S4[get_byte(3, L)];
33
34 R ^= P[j+1];
35 L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
36 S3[get_byte(2, R)]) + S4[get_byte(3, R)];
37 }
38
39 L ^= P[16]; R ^= P[17];
40
41 store_be(out, R, L);
42
43 in += BLOCK_SIZE;
44 out += BLOCK_SIZE;
45 }
46 }
47
48 /*
49 * Blowfish Decryption
50 */
51 void Blowfish::decrypt_n(const byte in[], byte out[], size_t blocks) const
52 {
53 const u32bit* S1 = &S[0];
54 const u32bit* S2 = &S[256];
55 const u32bit* S3 = &S[512];
56 const u32bit* S4 = &S[768];
57
58 for(size_t i = 0; i != blocks; ++i)
59 {
60 u32bit L = load_be<u32bit>(in, 0);
61 u32bit R = load_be<u32bit>(in, 1);
62
63 for(size_t j = 17; j != 1; j -= 2)
64 {
65 L ^= P[j];
66 R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
67 S3[get_byte(2, L)]) + S4[get_byte(3, L)];
68
69 R ^= P[j-1];
70 L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
71 S3[get_byte(2, R)]) + S4[get_byte(3, R)];
72 }
73
74 L ^= P[1]; R ^= P[0];
75
76 store_be(out, R, L);
77
78 in += BLOCK_SIZE;
79 out += BLOCK_SIZE;
80 }
81 }
82
83 /*
84 * Blowfish Key Schedule
85 */
86 void Blowfish::key_schedule(const byte key[], size_t length)
87 {
88 clear();
89
90 const byte null_salt[16] = { 0 };
91
92 key_expansion(key, length, null_salt);
93 }
94
95 void Blowfish::key_expansion(const byte key[],
96 size_t length,
97 const byte salt[16])
98 {
99 for(size_t i = 0, j = 0; i != 18; ++i, j += 4)
100 P[i] ^= make_u32bit(key[(j ) % length], key[(j+1) % length],
101 key[(j+2) % length], key[(j+3) % length]);
102
103 u32bit L = 0, R = 0;
104 generate_sbox(P, L, R, salt, 0);
105 generate_sbox(S, L, R, salt, 2);
106 }
107
108 /*
109 * Modified key schedule used for bcrypt password hashing
110 */
111 void Blowfish::eks_key_schedule(const byte key[], size_t length,
112 const byte salt[16], size_t workfactor)
113 {
114 if(length == 0 || length >= 56)
115 throw Invalid_Key_Length("EKSBlowfish", length);
116
117 if(workfactor == 0)
118 throw std::invalid_argument("Bcrypt work factor must be at least 1");
119
120 /*
121 * On a 2.8 GHz Core-i7, workfactor == 18 takes about 25 seconds to
122 * hash a password. This seems like a reasonable upper bound for the
123 * time being.
124 */
125 if(workfactor > 18)
126 throw std::invalid_argument("Requested Bcrypt work factor too large");
127
128 clear();
129
130 const byte null_salt[16] = { 0 };
131
132 key_expansion(key, length, salt);
133
134 const size_t rounds = 1 << workfactor;
135
136 for(size_t r = 0; r != rounds; ++r)
137 {
138 key_expansion(key, length, null_salt);
139 key_expansion(salt, 16, null_salt);
140 }
141 }
142
143 /*
144 * Generate one of the Sboxes
145 */
146 void Blowfish::generate_sbox(MemoryRegion<u32bit>& box,
147 u32bit& L, u32bit& R,
148 const byte salt[16],
149 size_t salt_off) const
150 {
151 const u32bit* S1 = &S[0];
152 const u32bit* S2 = &S[256];
153 const u32bit* S3 = &S[512];
154 const u32bit* S4 = &S[768];
155
156 for(size_t i = 0; i != box.size(); i += 2)
157 {
158 L ^= load_be<u32bit>(salt, (i + salt_off) % 4);
159 R ^= load_be<u32bit>(salt, (i + salt_off + 1) % 4);
160
161 for(size_t j = 0; j != 16; j += 2)
162 {
163 L ^= P[j];
164 R ^= ((S1[get_byte(0, L)] + S2[get_byte(1, L)]) ^
165 S3[get_byte(2, L)]) + S4[get_byte(3, L)];
166
167 R ^= P[j+1];
168 L ^= ((S1[get_byte(0, R)] + S2[get_byte(1, R)]) ^
169 S3[get_byte(2, R)]) + S4[get_byte(3, R)];
170 }
171
172 u32bit T = R; R = L ^ P[16]; L = T ^ P[17];
173 box[i] = L;
174 box[i+1] = R;
175 }
176 }
177
178 /*
179 * Clear memory of sensitive data
180 */
181 void Blowfish::clear()
182 {
183 std::copy(P_INIT, P_INIT + 18, P.begin());
184 std::copy(S_INIT, S_INIT + 1024, S.begin());
185 }
186
187 }
Botan::Blowfish::eks_key_schedule
void eks_key_schedule(const byte key[], size_t key_length, const byte salt[16], size_t workfactor)
Definition: blowfish.cpp:111
Botan::Invalid_Key_Length
Definition: exceptn.h:55
Botan::Block_Cipher_Fixed_Params< 8, 1, 56 >::BLOCK_SIZE
Definition: block_cipher.h:107
Botan::Blowfish::encrypt_n
void encrypt_n(const byte in[], byte out[], size_t blocks) const
Definition: blowfish.cpp:16
Botan::get_byte
byte get_byte(size_t byte_num, T input)
Definition: get_byte.h:21
Botan::byte
unsigned char byte
Definition: types.h:22
Botan::Blowfish::decrypt_n
void decrypt_n(const byte in[], byte out[], size_t blocks) const
Definition: blowfish.cpp:51
Botan::MemoryRegion::size
size_t size() const
Definition: secmem.h:29
Botan::MemoryRegion< u32bit >
Botan
Definition: algo_base.h:14
Botan::load_be< u32bit >
u32bit load_be< u32bit >(const byte in[], size_t off)
Definition: loadstor.h:166
Botan::MemoryRegion::begin
T * begin()
Definition: secmem.h:53
Botan::store_be
void store_be(u16bit in, byte out[2])
Definition: loadstor.h:412
Botan::Blowfish::clear
void clear()
Definition: blowfish.cpp:181
Botan::make_u32bit
u32bit make_u32bit(byte i0, byte i1, byte i2, byte i3)
Definition: loadstor.h:60
Botan::u32bit
unsigned int u32bit
Definition: types.h:32