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/*
* WiderWake
* (C) 1999-2007 Jack Lloyd
*
* Distributed under the terms of the Botan license
*/
#include <botan/wid_wake.h>
#include <botan/loadstor.h>
#include <botan/internal/xor_buf.h>
namespace Botan {
/*
* Combine cipher stream with message
*/
void WiderWake_41_BE::cipher(const byte in[], byte out[], size_t length)
{
while(length >= buffer.size() - position)
{
xor_buf(out, in, &buffer[position], buffer.size() - position);
length -= (buffer.size() - position);
in += (buffer.size() - position);
out += (buffer.size() - position);
generate(buffer.size());
}
xor_buf(out, in, &buffer[position], length);
position += length;
}
/*
* Generate cipher stream
*/
void WiderWake_41_BE::generate(size_t length)
{
u32bit R0 = state[0], R1 = state[1],
R2 = state[2], R3 = state[3],
R4 = state[4];
for(size_t i = 0; i != length; i += 8)
{
u32bit R0a;
store_be(R3, &buffer[i]);
R0a = R4 + R3; R3 += R2; R2 += R1; R1 += R0;
R0a = (R0a >> 8) ^ T[(R0a & 0xFF)];
R1 = (R1 >> 8) ^ T[(R1 & 0xFF)];
R2 = (R2 >> 8) ^ T[(R2 & 0xFF)];
R3 = (R3 >> 8) ^ T[(R3 & 0xFF)];
R4 = R0; R0 = R0a;
store_be(R3, &buffer[i + 4]);
R0a = R4 + R3; R3 += R2; R2 += R1; R1 += R0;
R0a = (R0a >> 8) ^ T[(R0a & 0xFF)];
R1 = (R1 >> 8) ^ T[(R1 & 0xFF)];
R2 = (R2 >> 8) ^ T[(R2 & 0xFF)];
R3 = (R3 >> 8) ^ T[(R3 & 0xFF)];
R4 = R0; R0 = R0a;
}
state[0] = R0;
state[1] = R1;
state[2] = R2;
state[3] = R3;
state[4] = R4;
position = 0;
}
/*
* WiderWake Key Schedule
*/
void WiderWake_41_BE::key_schedule(const byte key[], size_t)
{
for(size_t i = 0; i != 4; ++i)
t_key[i] = load_be<u32bit>(key, i);
static const u32bit MAGIC[8] = {
0x726A8F3B, 0xE69A3B5C, 0xD3C71FE5, 0xAB3C73D2,
0x4D3A8EB3, 0x0396D6E8, 0x3D4C2F7A, 0x9EE27CF3 };
for(size_t i = 0; i != 4; ++i)
T[i] = t_key[i];
for(size_t i = 4; i != 256; ++i)
{
u32bit X = T[i-1] + T[i-4];
T[i] = (X >> 3) ^ MAGIC[X % 8];
}
for(size_t i = 0; i != 23; ++i)
T[i] += T[i+89];
u32bit X = T[33];
u32bit Z = (T[59] | 0x01000001) & 0xFF7FFFFF;
for(size_t i = 0; i != 256; ++i)
{
X = (X & 0xFF7FFFFF) + Z;
T[i] = (T[i] & 0x00FFFFFF) ^ X;
}
X = (T[X & 0xFF] ^ X) & 0xFF;
Z = T[0];
T[0] = T[X];
for(size_t i = 1; i != 256; ++i)
{
T[X] = T[i];
X = (T[i ^ X] ^ X) & 0xFF;
T[i] = T[X];
}
T[X] = Z;
position = 0;
const byte ZEROS[8] = { 0 };
set_iv(ZEROS, sizeof(ZEROS));
}
/*
* Resynchronization
*/
void WiderWake_41_BE::set_iv(const byte iv[], size_t length)
{
if(!valid_iv_length(length))
throw Invalid_IV_Length(name(), length);
for(size_t i = 0; i != 4; ++i)
state[i] = t_key[i];
state[4] = load_be<u32bit>(iv, 0);
state[0] ^= state[4];
state[2] ^= load_be<u32bit>(iv, 1);
generate(8*4);
generate(buffer.size());
}
/*
* Clear memory of sensitive data
*/
void WiderWake_41_BE::clear()
{
position = 0;
zeroise(t_key);
zeroise(state);
zeroise(T);
zeroise(buffer);
}
}
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