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implement session and mac key if shared key is shorter than 64 bytes

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orignal 2014-04-15 11:53:24 -04:00
parent 002b023b29
commit 25e16f1693
1 changed files with 25 additions and 8 deletions
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33
SSU.cpp
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@ -1,7 +1,7 @@
#include <string.h>
#include <boost/bind.hpp>
#include <cryptopp/dh.h>
#include <cryptopp/secblock.h>
#include <cryptopp/sha.h>
#include "CryptoConst.h"
#include "Log.h"
#include "Timestamp.h"
@ -38,23 +38,40 @@ namespace ssu
void SSUSession::CreateAESandMacKey (const uint8_t * pubKey, uint8_t * aesKey, uint8_t * macKey)
{
CryptoPP::DH dh (i2p::crypto::elgp, i2p::crypto::elgg);
CryptoPP::SecByteBlock secretKey(dh.AgreedValueLength());
if (!dh.Agree (secretKey, m_DHKeysPair->privateKey, pubKey))
uint8_t sharedKey[64];
if (!dh.Agree (sharedKey, m_DHKeysPair->privateKey, pubKey))
{
LogPrint ("Couldn't create shared key");
return;
};
if (secretKey[0] & 0x80)
if (sharedKey[0] & 0x80)
{
aesKey[0] = 0;
memcpy (aesKey + 1, secretKey, 31);
memcpy (macKey, secretKey + 31, 32);
memcpy (aesKey + 1, sharedKey, 31);
memcpy (macKey, sharedKey + 31, 32);
}
else if (sharedKey[0])
{
memcpy (aesKey, sharedKey, 32);
memcpy (macKey, sharedKey + 32, 32);
}
else
{
memcpy (aesKey, secretKey, 32);
memcpy (macKey, secretKey + 32, 32);
// find first non-zero byte
uint8_t * nonZero = sharedKey + 1;
while (!*nonZero)
{
nonZero++;
if (nonZero - sharedKey > 32)
{
LogPrint ("First 32 bytes of shared key is all zeros. Ignored");
return;
}
}
memcpy (aesKey, nonZero, 32);
CryptoPP::SHA256().CalculateDigest(macKey, nonZero, 64 - (nonZero - sharedKey));
}
m_IsSessionKey = true;
}