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bug fix and optimization

pull/2/head
weidai 2002-10-06 03:58:13 +00:00
parent eee814871a
commit 6a286861f3
2 changed files with 46 additions and 21 deletions
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39
modes.cpp
View File

@ -72,10 +72,45 @@ void CTR_ModePolicy::SeekToIteration(dword iterationCount)
} }
} }
static inline void IncrementCounterByOne(byte *inout, unsigned int s)
{
for (int i=s-1, carry=1; i>=0 && carry; i--)
carry = !++inout[i];
}
static inline void IncrementCounterByOne(byte *output, const byte *input, unsigned int s)
{
for (int i=s-1, carry=1; i>=0; i--)
carry = !(output[i] = input[i]+carry) && carry;
}
inline void CTR_ModePolicy::ProcessMultipleBlocks(byte *output, const byte *input, unsigned int n)
{
unsigned int s = BlockSize(), j = 0;
for (unsigned int i=1; i<n; i++, j+=s)
IncrementCounterByOne(m_counterArray + j + s, m_counterArray + j, s);
m_cipher->ProcessAndXorMultipleBlocks(m_counterArray, input, output, n);
IncrementCounterByOne(m_counterArray, m_counterArray + s*(n-1), s);
}
void CTR_ModePolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, unsigned int iterationCount) void CTR_ModePolicy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, unsigned int iterationCount)
{ {
unsigned int maxBlocks = m_cipher->OptimalNumberOfParallelBlocks(); unsigned int maxBlocks = m_cipher->OptimalNumberOfParallelBlocks();
unsigned int sizeIncrement = maxBlocks * m_cipher->BlockSize(); if (maxBlocks == 1)
{
unsigned int sizeIncrement = BlockSize();
while (iterationCount)
{
m_cipher->ProcessAndXorBlock(m_counterArray, input, output);
IncrementCounterByOne(m_counterArray, sizeIncrement);
output += sizeIncrement;
input += sizeIncrement;
iterationCount -= 1;
}
}
else
{
unsigned int sizeIncrement = maxBlocks * BlockSize();
while (iterationCount >= maxBlocks) while (iterationCount >= maxBlocks)
{ {
ProcessMultipleBlocks(output, input, maxBlocks); ProcessMultipleBlocks(output, input, maxBlocks);
@ -85,7 +120,9 @@ void CTR_ModePolicy::OperateKeystream(KeystreamOperation operation, byte *output
} }
if (iterationCount > 0) if (iterationCount > 0)
ProcessMultipleBlocks(output, input, iterationCount); ProcessMultipleBlocks(output, input, iterationCount);
}
} }
void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv) void CTR_ModePolicy::CipherResynchronize(byte *keystreamBuffer, const byte *iv)
{ {
unsigned int s = BlockSize(); unsigned int s = BlockSize();

14
modes.h
View File

@ -142,19 +142,7 @@ class CTR_ModePolicy : public ModePolicyCommonTemplate<AdditiveCipherAbstractPol
void SeekToIteration(dword iterationCount); void SeekToIteration(dword iterationCount);
IV_Requirement IVRequirement() const {return STRUCTURED_IV;} IV_Requirement IVRequirement() const {return STRUCTURED_IV;}
static inline void IncrementCounterByOne(byte *output, const byte *input, unsigned int s) inline void ProcessMultipleBlocks(byte *output, const byte *input, unsigned int n);
{
for (int i=s-1, carry=1; i>=0; i--)
carry = !(output[i] = input[i]+1);
}
inline void ProcessMultipleBlocks(byte *output, const byte *input, unsigned int n)
{
unsigned int s = BlockSize(), j = 0;
for (unsigned int i=1; i<n; i++, j+=s)
IncrementCounterByOne(m_counterArray + j + s, m_counterArray + j, s);
m_cipher->ProcessAndXorMultipleBlocks(m_counterArray, input, output, n);
IncrementCounterByOne(m_counterArray, m_counterArray + s*(n-1), s);
}
SecByteBlock m_counterArray; SecByteBlock m_counterArray;
}; };