124 lines
2.8 KiB
C++
124 lines
2.8 KiB
C++
// serpent.cpp - written and placed in the public domain by Wei Dai
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#include "pch.h"
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#include "serpent.h"
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#include "misc.h"
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#include "serpentp.h"
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NAMESPACE_BEGIN(CryptoPP)
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void Serpent_KeySchedule(word32 *k, unsigned int rounds, const byte *userKey, size_t keylen)
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{
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FixedSizeSecBlock<word32, 8> k0;
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GetUserKey(LITTLE_ENDIAN_ORDER, k0.begin(), 8, userKey, keylen);
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if (keylen < 32)
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k0[keylen/4] |= word32(1) << ((keylen%4)*8);
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word32 t = k0[7];
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unsigned int i;
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for (i = 0; i < 8; ++i)
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k[i] = k0[i] = t = rotlFixed(k0[i] ^ k0[(i+3)%8] ^ k0[(i+5)%8] ^ t ^ 0x9e3779b9 ^ i, 11);
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for (i = 8; i < 4*(rounds+1); ++i)
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k[i] = t = rotlFixed(k[i-8] ^ k[i-5] ^ k[i-3] ^ t ^ 0x9e3779b9 ^ i, 11);
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k -= 20;
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word32 a,b,c,d,e;
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for (i=0; i<rounds/8; i++)
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{
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afterS2(LK); afterS2(S3); afterS3(SK);
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afterS1(LK); afterS1(S2); afterS2(SK);
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afterS0(LK); afterS0(S1); afterS1(SK);
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beforeS0(LK); beforeS0(S0); afterS0(SK);
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k += 8*4;
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afterS6(LK); afterS6(S7); afterS7(SK);
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afterS5(LK); afterS5(S6); afterS6(SK);
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afterS4(LK); afterS4(S5); afterS5(SK);
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afterS3(LK); afterS3(S4); afterS4(SK);
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}
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afterS2(LK); afterS2(S3); afterS3(SK);
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}
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void Serpent::Base::UncheckedSetKey(const byte *userKey, unsigned int keylen, const NameValuePairs &)
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{
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AssertValidKeyLength(keylen);
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Serpent_KeySchedule(m_key, 32, userKey, keylen);
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}
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typedef BlockGetAndPut<word32, LittleEndian> Block;
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void Serpent::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 a, b, c, d, e;
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Block::Get(inBlock)(a)(b)(c)(d);
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const word32 *k = m_key;
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unsigned int i=1;
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do
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{
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beforeS0(KX); beforeS0(S0); afterS0(LT);
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afterS0(KX); afterS0(S1); afterS1(LT);
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afterS1(KX); afterS1(S2); afterS2(LT);
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afterS2(KX); afterS2(S3); afterS3(LT);
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afterS3(KX); afterS3(S4); afterS4(LT);
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afterS4(KX); afterS4(S5); afterS5(LT);
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afterS5(KX); afterS5(S6); afterS6(LT);
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afterS6(KX); afterS6(S7);
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if (i == 4)
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break;
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++i;
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c = b;
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b = e;
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e = d;
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d = a;
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a = e;
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k += 32;
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beforeS0(LT);
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}
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while (true);
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afterS7(KX);
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Block::Put(xorBlock, outBlock)(d)(e)(b)(a);
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}
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void Serpent::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
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{
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word32 a, b, c, d, e;
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Block::Get(inBlock)(a)(b)(c)(d);
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const word32 *k = m_key + 96;
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unsigned int i=4;
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beforeI7(KX);
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goto start;
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do
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{
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c = b;
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b = d;
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d = e;
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k -= 32;
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beforeI7(ILT);
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start:
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beforeI7(I7); afterI7(KX);
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afterI7(ILT); afterI7(I6); afterI6(KX);
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afterI6(ILT); afterI6(I5); afterI5(KX);
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afterI5(ILT); afterI5(I4); afterI4(KX);
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afterI4(ILT); afterI4(I3); afterI3(KX);
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afterI3(ILT); afterI3(I2); afterI2(KX);
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afterI2(ILT); afterI2(I1); afterI1(KX);
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afterI1(ILT); afterI1(I0); afterI0(KX);
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}
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while (--i != 0);
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Block::Put(xorBlock, outBlock)(a)(d)(b)(e);
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}
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NAMESPACE_END
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