260 lines
8.8 KiB
C++
260 lines
8.8 KiB
C++
// rabbit.cpp - written and placed in the public domain by Jeffrey Walton
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// based on public domain code by Martin Boesgaard, Mette Vesterager,
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// Thomas Pedersen, Jesper Christiansen and Ove Scavenius.
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//
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// The reference materials and source files are available at
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// The eSTREAM Project, http://www.ecrypt.eu.org/stream/e2-rabbit.html.
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#include "pch.h"
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#include "config.h"
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#include "rabbit.h"
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#include "secblock.h"
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#include "misc.h"
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ANONYMOUS_NAMESPACE_BEGIN
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using CryptoPP::word32;
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using CryptoPP::word64;
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using CryptoPP::rotlConstant;
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word32 G_func(word32 x)
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{
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#if 0
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/* Temporary variables */
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word32 a, b, h, l;
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/* Construct high and low argument for squaring */
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a = x & 0xFFFF;
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b = x >> 16;
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/* Calculate high and low result of squaring */
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h = (((static_cast<word32>(a*a) >> 17U) + static_cast<word32>(a*b)) >> 15U) + b*b;
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l = x*x;
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/* Return high XOR low */
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return static_cast<word32>(h^l);
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#endif
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// Thanks to Jack Lloyd for suggesting the 64-bit multiply.
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word64 z = x;
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z *= x;
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return static_cast<word32>((z >> 32) ^ z);
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}
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word32 NextState(word32 c[8], word32 x[8], word32 carry)
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{
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/* Temporary variables */
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word32 g[8], c_old[8], i;
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/* Save old counter values */
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for (i = 0; i<8; i++)
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c_old[i] = c[i];
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/* Calculate new counter values */
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c[0] = static_cast<word32>(c[0] + 0x4D34D34D + carry);
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c[1] = static_cast<word32>(c[1] + 0xD34D34D3 + (c[0] < c_old[0]));
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c[2] = static_cast<word32>(c[2] + 0x34D34D34 + (c[1] < c_old[1]));
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c[3] = static_cast<word32>(c[3] + 0x4D34D34D + (c[2] < c_old[2]));
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c[4] = static_cast<word32>(c[4] + 0xD34D34D3 + (c[3] < c_old[3]));
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c[5] = static_cast<word32>(c[5] + 0x34D34D34 + (c[4] < c_old[4]));
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c[6] = static_cast<word32>(c[6] + 0x4D34D34D + (c[5] < c_old[5]));
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c[7] = static_cast<word32>(c[7] + 0xD34D34D3 + (c[6] < c_old[6]));
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carry = (c[7] < c_old[7]);
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/* Calculate the g-values */
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for (i = 0; i<8; i++)
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g[i] = G_func(static_cast<word32>(x[i] + c[i]));
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/* Calculate new state values */
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x[0] = static_cast<word32>(g[0] + rotlConstant<16>(g[7]) + rotlConstant<16>(g[6]));
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x[1] = static_cast<word32>(g[1] + rotlConstant<8>(g[0]) + g[7]);
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x[2] = static_cast<word32>(g[2] + rotlConstant<16>(g[1]) + rotlConstant<16>(g[0]));
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x[3] = static_cast<word32>(g[3] + rotlConstant<8>(g[2]) + g[1]);
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x[4] = static_cast<word32>(g[4] + rotlConstant<16>(g[3]) + rotlConstant<16>(g[2]));
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x[5] = static_cast<word32>(g[5] + rotlConstant<8>(g[4]) + g[3]);
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x[6] = static_cast<word32>(g[6] + rotlConstant<16>(g[5]) + rotlConstant<16>(g[4]));
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x[7] = static_cast<word32>(g[7] + rotlConstant<8>(g[6]) + g[5]);
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return carry;
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}
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ANONYMOUS_NAMESPACE_END
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NAMESPACE_BEGIN(CryptoPP)
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void RabbitPolicy::CipherSetKey(const NameValuePairs ¶ms, const byte *userKey, size_t keylen)
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{
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/* Generate four subkeys */
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CRYPTOPP_UNUSED(params);
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GetUserKey(LITTLE_ENDIAN_ORDER, m_t.begin(), 4, userKey, keylen);
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/* Generate initial state variables */
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m_mx[0] = m_t[0];
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m_mx[2] = m_t[1];
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m_mx[4] = m_t[2];
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m_mx[6] = m_t[3];
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m_mx[1] = static_cast<word32>(m_t[3] << 16) | (m_t[2] >> 16);
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m_mx[3] = static_cast<word32>(m_t[0] << 16) | (m_t[3] >> 16);
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m_mx[5] = static_cast<word32>(m_t[1] << 16) | (m_t[0] >> 16);
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m_mx[7] = static_cast<word32>(m_t[2] << 16) | (m_t[1] >> 16);
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/* Generate initial counter values */
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m_mc[0] = rotlConstant<16>(m_t[2]);
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m_mc[2] = rotlConstant<16>(m_t[3]);
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m_mc[4] = rotlConstant<16>(m_t[0]);
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m_mc[6] = rotlConstant<16>(m_t[1]);
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m_mc[1] = (m_t[0] & 0xFFFF0000) | (m_t[1] & 0xFFFF);
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m_mc[3] = (m_t[1] & 0xFFFF0000) | (m_t[2] & 0xFFFF);
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m_mc[5] = (m_t[2] & 0xFFFF0000) | (m_t[3] & 0xFFFF);
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m_mc[7] = (m_t[3] & 0xFFFF0000) | (m_t[0] & 0xFFFF);
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/* Clear carry bit */
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m_mcy = 0;
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/* Iterate the system four times */
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for (unsigned int i = 0; i<4; i++)
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m_mcy = NextState(m_mc, m_mx, m_mcy);
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/* Modify the counters */
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for (unsigned int i = 0; i<8; i++)
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m_mc[i] ^= m_mx[(i + 4) & 0x7];
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/* Copy master instance to work instance */
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for (unsigned int i = 0; i<8; i++)
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{
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m_wx[i] = m_mx[i];
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m_wc[i] = m_mc[i];
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}
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m_wcy = m_mcy;
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}
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void RabbitPolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
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{
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byte* out = output;
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for (size_t i = 0; i<iterationCount; ++i, out += 16)
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{
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/* Iterate the system */
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m_wcy = NextState(m_wc, m_wx, m_wcy);
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/* Encrypt/decrypt 16 bytes of data */
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 0, m_wx[0] ^ (m_wx[5] >> 16) ^ (m_wx[3] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 4, m_wx[2] ^ (m_wx[7] >> 16) ^ (m_wx[5] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 8, m_wx[4] ^ (m_wx[1] >> 16) ^ (m_wx[7] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 12, m_wx[6] ^ (m_wx[3] >> 16) ^ (m_wx[1] << 16));
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}
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// If AdditiveCipherTemplate does not have an accumulated keystream
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// then it will ask OperateKeystream to generate one. Optionally it
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// will ask for an XOR of the input with the keystream while
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// writing the result to the output buffer. In all cases the
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// keystream is written to the output buffer. The optional part is
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// adding the input buffer and keystream.
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if ((operation & EnumToInt(INPUT_NULL)) != EnumToInt(INPUT_NULL))
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xorbuf(output, input, GetBytesPerIteration() * iterationCount);
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}
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void RabbitWithIVPolicy::CipherSetKey(const NameValuePairs ¶ms, const byte *userKey, size_t keylen)
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{
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/* Generate four subkeys */
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CRYPTOPP_UNUSED(params);
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GetUserKey(LITTLE_ENDIAN_ORDER, m_t.begin(), 4, userKey, keylen);
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/* Generate initial state variables */
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m_mx[0] = m_t[0];
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m_mx[2] = m_t[1];
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m_mx[4] = m_t[2];
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m_mx[6] = m_t[3];
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m_mx[1] = static_cast<word32>(m_t[3] << 16) | (m_t[2] >> 16);
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m_mx[3] = static_cast<word32>(m_t[0] << 16) | (m_t[3] >> 16);
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m_mx[5] = static_cast<word32>(m_t[1] << 16) | (m_t[0] >> 16);
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m_mx[7] = static_cast<word32>(m_t[2] << 16) | (m_t[1] >> 16);
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/* Generate initial counter values */
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m_mc[0] = rotlConstant<16>(m_t[2]);
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m_mc[2] = rotlConstant<16>(m_t[3]);
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m_mc[4] = rotlConstant<16>(m_t[0]);
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m_mc[6] = rotlConstant<16>(m_t[1]);
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m_mc[1] = (m_t[0] & 0xFFFF0000) | (m_t[1] & 0xFFFF);
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m_mc[3] = (m_t[1] & 0xFFFF0000) | (m_t[2] & 0xFFFF);
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m_mc[5] = (m_t[2] & 0xFFFF0000) | (m_t[3] & 0xFFFF);
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m_mc[7] = (m_t[3] & 0xFFFF0000) | (m_t[0] & 0xFFFF);
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/* Clear carry bit */
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m_mcy = 0;
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/* Iterate the system four times */
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for (unsigned int i = 0; i<4; i++)
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m_mcy = NextState(m_mc, m_mx, m_mcy);
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/* Modify the counters */
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for (unsigned int i = 0; i<8; i++)
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m_mc[i] ^= m_mx[(i + 4) & 0x7];
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/* Copy master instance to work instance */
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for (unsigned int i = 0; i<8; i++)
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{
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m_wx[i] = m_mx[i];
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m_wc[i] = m_mc[i];
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}
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m_wcy = m_mcy;
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}
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void RabbitWithIVPolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv, size_t length)
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{
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CRYPTOPP_UNUSED(keystreamBuffer);
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CRYPTOPP_UNUSED(length);
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CRYPTOPP_ASSERT(length == 8);
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/* Generate four subvectors */
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GetBlock<word32, LittleEndian> v(iv); v(m_t[0])(m_t[2]);
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m_t[1] = (m_t[0] >> 16) | (m_t[2] & 0xFFFF0000);
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m_t[3] = (m_t[2] << 16) | (m_t[0] & 0x0000FFFF);
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/* Modify counter values */
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m_wc[0] = m_mc[0] ^ m_t[0];
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m_wc[1] = m_mc[1] ^ m_t[1];
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m_wc[2] = m_mc[2] ^ m_t[2];
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m_wc[3] = m_mc[3] ^ m_t[3];
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m_wc[4] = m_mc[4] ^ m_t[0];
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m_wc[5] = m_mc[5] ^ m_t[1];
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m_wc[6] = m_mc[6] ^ m_t[2];
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m_wc[7] = m_mc[7] ^ m_t[3];
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/* Copy state variables */
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for (unsigned int i = 0; i<8; i++)
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m_wx[i] = m_mx[i];
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m_wcy = m_mcy;
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/* Iterate the system four times */
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for (unsigned int i = 0; i<4; i++)
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m_wcy = NextState(m_wc, m_wx, m_wcy);
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}
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void RabbitWithIVPolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
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{
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byte* out = output;
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for (unsigned int i = 0; i<iterationCount; ++i, out += 16)
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{
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/* Iterate the system */
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m_wcy = NextState(m_wc, m_wx, m_wcy);
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/* Encrypt/decrypt 16 bytes of data */
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 0, m_wx[0] ^ (m_wx[5] >> 16) ^ (m_wx[3] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 4, m_wx[2] ^ (m_wx[7] >> 16) ^ (m_wx[5] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 8, m_wx[4] ^ (m_wx[1] >> 16) ^ (m_wx[7] << 16));
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PutWord(false, LITTLE_ENDIAN_ORDER, out + 12, m_wx[6] ^ (m_wx[3] >> 16) ^ (m_wx[1] << 16));
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}
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// If AdditiveCipherTemplate does not have an accumulated keystream
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// then it will ask OperateKeystream to generate one. Optionally it
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// will ask for an XOR of the input with the keystream while
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// writing the result to the output buffer. In all cases the
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// keystream is written to the output buffer. The optional part is
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// adding the input buffer and keystream.
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if ((operation & EnumToInt(INPUT_NULL)) != EnumToInt(INPUT_NULL))
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xorbuf(output, input, GetBytesPerIteration() * iterationCount);
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}
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NAMESPACE_END
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