Crypto++ 8.1 Free C++ class library of cryptographic schemes

serpent.cpp
1 // serpent.cpp - originally written and placed in the public domain by Wei Dai
2
3 #include "pch.h"
4
5 #include "serpent.h"
6 #include "secblock.h"
7 #include "misc.h"
8
9 #include "serpentp.h"
10
11 NAMESPACE_BEGIN(CryptoPP)
12
13 void Serpent_KeySchedule(word32 *k, unsigned int rounds, const byte *userKey, size_t keylen)
14 {
15 FixedSizeSecBlock<word32, 8> k0;
16 GetUserKey(LITTLE_ENDIAN_ORDER, k0.begin(), 8, userKey, keylen);
17 if (keylen < 32)
18 k0[keylen/4] |= word32(1) << ((keylen%4)*8);
19
20 word32 t = k0[7];
21 unsigned int i;
22 for (i = 0; i < 8; ++i)
23 k[i] = k0[i] = t = rotlConstant<11>(k0[i] ^ k0[(i + 3) % 8] ^ k0[(i + 5) % 8] ^ t ^ 0x9e3779b9 ^ i);
24 for (i = 8; i < 4*(rounds+1); ++i)
25 k[i] = t = rotlConstant<11>(k[i-8] ^ k[i-5] ^ k[i-3] ^ t ^ 0x9e3779b9 ^ i);
26 k -= 20;
27
28 word32 a,b,c,d,e;
29 for (i=0; i<rounds/8; i++)
30 {
31 afterS2(LK); afterS2(S3); afterS3(SK);
32 afterS1(LK); afterS1(S2); afterS2(SK);
33 afterS0(LK); afterS0(S1); afterS1(SK);
34 beforeS0(LK); beforeS0(S0); afterS0(SK);
35 k += 8*4;
36 afterS6(LK); afterS6(S7); afterS7(SK);
37 afterS5(LK); afterS5(S6); afterS6(SK);
38 afterS4(LK); afterS4(S5); afterS5(SK);
39 afterS3(LK); afterS3(S4); afterS4(SK);
40 }
41 afterS2(LK); afterS2(S3); afterS3(SK);
42 }
43
44 void Serpent::Base::UncheckedSetKey(const byte *userKey, unsigned int keylen, const NameValuePairs &)
45 {
46 AssertValidKeyLength(keylen);
47 Serpent_KeySchedule(m_key, 32, userKey, keylen);
48 }
49
50 typedef BlockGetAndPut<word32, LittleEndian> Block;
51
52 void Serpent::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
53 {
54 word32 a, b, c, d, e;
55
56 Block::Get(inBlock)(a)(b)(c)(d);
57
58 const word32 *k = m_key;
59 unsigned int i=1;
60
61 do
62 {
63 beforeS0(KX); beforeS0(S0); afterS0(LT);
64 afterS0(KX); afterS0(S1); afterS1(LT);
65 afterS1(KX); afterS1(S2); afterS2(LT);
66 afterS2(KX); afterS2(S3); afterS3(LT);
67 afterS3(KX); afterS3(S4); afterS4(LT);
68 afterS4(KX); afterS4(S5); afterS5(LT);
69 afterS5(KX); afterS5(S6); afterS6(LT);
70 afterS6(KX); afterS6(S7);
71
72 if (i == 4)
73 break;
74
75 ++i;
76 c = b;
77 b = e;
78 e = d;
79 d = a;
80 a = e;
81 k += 32;
82 beforeS0(LT);
83 }
84 while (true);
85
86 afterS7(KX);
87
88 Block::Put(xorBlock, outBlock)(d)(e)(b)(a);
89 }
90
91 void Serpent::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
92 {
93 word32 a, b, c, d, e=0;
94
95 Block::Get(inBlock)(a)(b)(c)(d);
96
97 const word32 *k = m_key + 96;
98 unsigned int i=4;
99
100 beforeI7(KX);
101 goto start;
102
103 do
104 {
105 c = b;
106 b = d;
107 d = e;
108 k -= 32;
109 beforeI7(ILT);
110 start:
111 beforeI7(I7); afterI7(KX);
112 afterI7(ILT); afterI7(I6); afterI6(KX);
113 afterI6(ILT); afterI6(I5); afterI5(KX);
114 afterI5(ILT); afterI5(I4); afterI4(KX);
115 afterI4(ILT); afterI4(I3); afterI3(KX);
116 afterI3(ILT); afterI3(I2); afterI2(KX);
117 afterI2(ILT); afterI2(I1); afterI1(KX);
118 afterI1(ILT); afterI1(I0); afterI0(KX);
119 }
120 while (--i != 0);
121
122 Block::Put(xorBlock, outBlock)(a)(d)(b)(e);
123 }
124
125 NAMESPACE_END
misc.h
Utility functions for the Crypto++ library.
BlockGetAndPut
Access a block of memory.
Definition: misc.h:2500
LITTLE_ENDIAN_ORDER
byte order is little-endian
Definition: cryptlib.h:145
secblock.h
Classes and functions for secure memory allocations.
pch.h
Precompiled header file.
FixedSizeSecBlock< word32, 8 >
PutBlock
Access a block of memory.
Definition: misc.h:2463
serpent.h
Classes for the Serpent block cipher.
CryptoPP
Crypto++ library namespace.
NameValuePairs
Interface for retrieving values given their names.
Definition: cryptlib.h:293