64 lines
1.4 KiB
C++
64 lines
1.4 KiB
C++
// randpool.cpp - written and placed in the public domain by Wei Dai
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// RandomPool used to follow the design of randpool in PGP 2.6.x,
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// but as of version 5.5 it has been redesigned to reduce the risk
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// of reusing random numbers after state rollback (which may occur
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// when running in a virtual machine like VMware).
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#include "pch.h"
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#ifndef CRYPTOPP_IMPORTS
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#include "randpool.h"
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#include "aes.h"
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#include "sha.h"
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#include "hrtimer.h"
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#include <time.h>
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NAMESPACE_BEGIN(CryptoPP)
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RandomPool::RandomPool()
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: m_pCipher(new AES::Encryption), m_keySet(false)
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{
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memset(m_key, 0, m_key.SizeInBytes());
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memset(m_seed, 0, m_seed.SizeInBytes());
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}
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void RandomPool::IncorporateEntropy(const byte *input, size_t length)
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{
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SHA256 hash;
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hash.Update(m_key, 32);
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hash.Update(input, length);
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hash.Final(m_key);
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m_keySet = false;
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}
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void RandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
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{
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if (size > 0)
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{
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if (!m_keySet)
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m_pCipher->SetKey(m_key, 32);
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Timer timer;
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TimerWord tw = timer.GetCurrentTimerValue();
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CRYPTOPP_COMPILE_ASSERT(sizeof(tw) <= 16);
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*(TimerWord *)m_seed.data() += tw;
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time_t t = time(NULL);
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CRYPTOPP_COMPILE_ASSERT(sizeof(t) <= 8);
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*(time_t *)(m_seed.data()+8) += t;
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do
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{
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m_pCipher->ProcessBlock(m_seed);
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size_t len = UnsignedMin(16, size);
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target.ChannelPut(channel, m_seed, len);
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size -= len;
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} while (size > 0);
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}
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}
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NAMESPACE_END
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#endif
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