1// 3way.cpp - modifed by Wei Dai from Joan Daemen's 3way.c
2// The original code and all modifications are in the public domain.
3
4#include "pch.h"
5#include "3way.h"
6#include "misc.h"
7
8NAMESPACE_BEGIN(CryptoPP)
9
10void ThreeWay_TestInstantiations()
11{
12	ThreeWay::Encryption x1;
13	ThreeWay::Decryption x2;
14}
15
16static const word32 START_E = 0x0b0b; // round constant of first encryption round
17static const word32 START_D = 0xb1b1; // round constant of first decryption round
18static const word32 RC_MODULUS = 0x11011;
19
20static inline word32 reverseBits(word32 a)
21{
22	a = ((a & 0xAAAAAAAA) >> 1) | ((a & 0x55555555) << 1);
23	a = ((a & 0xCCCCCCCC) >> 2) | ((a & 0x33333333) << 2);
24	return ((a & 0xF0F0F0F0) >> 4) | ((a & 0x0F0F0F0F) << 4);
25}
26
27#define mu(a0, a1, a2)				\
28{									\
29	a1 = reverseBits(a1);			\
30	word32 t = reverseBits(a0);		\
31	a0 = reverseBits(a2);			\
32	a2 = t;							\
33}
34
35#define pi_gamma_pi(a0, a1, a2)		\
36{									\
37	word32 b0, b2;					\
38	b2 = rotlFixed(a2, 1U);				\
39	b0 = rotlFixed(a0, 22U);				\
40	a0 = rotlFixed(b0 ^ (a1|(~b2)), 1U);	\
41	a2 = rotlFixed(b2 ^ (b0|(~a1)), 22U);\
42	a1 ^= (b2|(~b0));				\
43}
44
45// thanks to Paulo Barreto for this optimized theta()
46#define theta(a0, a1, a2)									\
47{ 															\
48	word32 b0, b1, c; 										\
49	c = a0 ^ a1 ^ a2; 										\
50	c = rotlFixed(c, 16U) ^ rotlFixed(c, 8U);				\
51	b0 = (a0 << 24) ^ (a2 >> 8) ^ (a1 << 8) ^ (a0 >> 24); 	\
52	b1 = (a1 << 24) ^ (a0 >> 8) ^ (a2 << 8) ^ (a1 >> 24); 	\
53	a0 ^= c ^ b0; 											\
54	a1 ^= c ^ b1; 											\
55	a2 ^= c ^ (b0 >> 16) ^ (b1 << 16); 						\
56}
57
58#define rho(a0, a1, a2)			\
59{								\
60	theta(a0, a1, a2);			\
61	pi_gamma_pi(a0, a1, a2);	\
62}
63
64void ThreeWay::Base::UncheckedSetKey(const byte *uk, unsigned int length, const NameValuePairs &params)
65{
66	AssertValidKeyLength(length);
67
68	m_rounds = GetRoundsAndThrowIfInvalid(params, this);
69
70	for (unsigned int i=0; i<3; i++)
71		m_k[i] = (word32)uk[4*i+3] | ((word32)uk[4*i+2]<<8) | ((word32)uk[4*i+1]<<16) | ((word32)uk[4*i]<<24);
72
73	if (!IsForwardTransformation())
74	{
75		theta(m_k[0], m_k[1], m_k[2]);
76		mu(m_k[0], m_k[1], m_k[2]);
77		m_k[0] = ByteReverse(m_k[0]);
78		m_k[1] = ByteReverse(m_k[1]);
79		m_k[2] = ByteReverse(m_k[2]);
80	}
81}
82
83void ThreeWay::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
84{
85	typedef BlockGetAndPut<word32, BigEndian> Block;
86
87	word32 a0, a1, a2;
88	Block::Get(inBlock)(a0)(a1)(a2);
89
90	word32 rc = START_E;
91
92	for(unsigned i=0; i<m_rounds; i++)
93	{
94		a0 ^= m_k[0] ^ (rc<<16);
95		a1 ^= m_k[1];
96		a2 ^= m_k[2] ^ rc;
97		rho(a0, a1, a2);
98
99		rc <<= 1;
100		if (rc&0x10000) rc ^= 0x11011;
101	}
102	a0 ^= m_k[0] ^ (rc<<16);
103	a1 ^= m_k[1];
104	a2 ^= m_k[2] ^ rc;
105	theta(a0, a1, a2);
106
107	Block::Put(xorBlock, outBlock)(a0)(a1)(a2);
108}
109
110void ThreeWay::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
111{
112	typedef BlockGetAndPut<word32, LittleEndian> Block;
113
114	word32 a0, a1, a2;
115	Block::Get(inBlock)(a0)(a1)(a2);
116
117	word32 rc = START_D;
118
119	mu(a0, a1, a2);
120	for(unsigned i=0; i<m_rounds; i++)
121	{
122		a0 ^= m_k[0] ^ (rc<<16);
123		a1 ^= m_k[1];
124		a2 ^= m_k[2] ^ rc;
125		rho(a0, a1, a2);
126
127		rc <<= 1;
128		if (rc&0x10000) rc ^= 0x11011;
129	}
130	a0 ^= m_k[0] ^ (rc<<16);
131	a1 ^= m_k[1];
132	a2 ^= m_k[2] ^ rc;
133	theta(a0, a1, a2);
134	mu(a0, a1, a2);
135
136	Block::Put(xorBlock, outBlock)(a0)(a1)(a2);
137}
138
139NAMESPACE_END
140