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korayakov
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Файл:Документация по криптоалгоритмам / CRYPTO30 / randpool
.cpp// randpool.cpp - written and placed in the public domain by Wei Dai
// The algorithm in this module comes from PGP's randpool.c
#include "pch.h"
#include "randpool.h"
#include "mdc.h"
#include "md5.h"
#include "modes.h"
NAMESPACE_BEGIN(CryptoPP)
typedef MDC<MD5> RandomPoolCipher;
RandomPool::RandomPool(unsigned int poolSize)
: pool(poolSize), key(RandomPoolCipher::KEYLENGTH)
{
assert(poolSize > key.size);
addPos=0;
getPos=poolSize;
memset(pool, 0, poolSize);
memset(key, 0, key.size);
}
void RandomPool::Stir()
{
// add these lines to be compatible with PGP's randpool.c
// byteReverse((word32 *)pool.ptr, (word32 *)pool.ptr, pool.size);
for (int i=0; i<2; i++)
{
RandomPoolCipher cipher(key);
CFBEncryption cfb(cipher, pool+pool.size-cipher.BlockSize());
cfb.ProcessString(pool, pool.size);
memcpy(key, pool, key.size);
}
// byteReverse((word32 *)pool.ptr, (word32 *)pool.ptr, pool.size);
addPos = 0;
getPos = key.size;
}
void RandomPool::Put(byte inByte)
{
if (addPos == pool.size)
Stir();
pool[addPos++] ^= inByte;
getPos = pool.size; // Force stir on get
}
void RandomPool::Put(const byte *inString, unsigned int length)
{
unsigned t;
while (length > (t = pool.size - addPos))
{
xorbuf(pool+addPos, inString, t);
inString += t;
length -= t;
Stir();
}
if (length)
{
xorbuf(pool+addPos, inString, length);
addPos += length;
getPos = pool.size; // Force stir on get
}
}
unsigned int RandomPool::Get(byte &outByte)
{
if (getPos == pool.size)
Stir();
outByte = pool[getPos++];
return 1;
}
unsigned int RandomPool::Get(byte *outString, unsigned int getMax)
{
unsigned t;
unsigned int length = getMax;
while (length > (t = pool.size - getPos))
{
memcpy(outString, pool+getPos, t);
outString += t;
length -= t;
Stir();
}
if (length)
{
memcpy(outString, pool+getPos, length);
getPos += length;
}
return getMax;
}
unsigned int RandomPool::Peek(byte &outByte) const
{
if (getPos == pool.size)
const_cast<RandomPool *>(this)->Stir();
outByte = pool[getPos];
return 1;
}
NAMESPACE_END
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