00001
00002
00003 #include "pch.h"
00004 #include "eax.h"
00005
00006 NAMESPACE_BEGIN(CryptoPP)
00007
00008 void EAX_Base::SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs ¶ms)
00009 {
00010 AccessMAC().SetKey(userKey, keylength, params);
00011 m_buffer.New(2*AccessMAC().TagSize());
00012 }
00013
00014 void EAX_Base::Resync(const byte *iv, size_t len)
00015 {
00016 MessageAuthenticationCode &mac = AccessMAC();
00017 unsigned int blockSize = mac.TagSize();
00018
00019 memset(m_buffer, 0, blockSize);
00020 mac.Update(m_buffer, blockSize);
00021 mac.CalculateDigest(m_buffer+blockSize, iv, len);
00022
00023 m_buffer[blockSize-1] = 1;
00024 mac.Update(m_buffer, blockSize);
00025
00026 m_ctr.SetCipherWithIV(AccessMAC().AccessCipher(), m_buffer+blockSize, blockSize);
00027 }
00028
00029 size_t EAX_Base::AuthenticateBlocks(const byte *data, size_t len)
00030 {
00031 AccessMAC().Update(data, len);
00032 return 0;
00033 }
00034
00035 void EAX_Base::AuthenticateLastHeaderBlock()
00036 {
00037 assert(m_bufferedDataLength == 0);
00038 MessageAuthenticationCode &mac = AccessMAC();
00039 unsigned int blockSize = mac.TagSize();
00040
00041 mac.Final(m_buffer);
00042 xorbuf(m_buffer+blockSize, m_buffer, blockSize);
00043
00044 memset(m_buffer, 0, blockSize);
00045 m_buffer[blockSize-1] = 2;
00046 mac.Update(m_buffer, blockSize);
00047 }
00048
00049 void EAX_Base::AuthenticateLastFooterBlock(byte *tag, size_t macSize)
00050 {
00051 assert(m_bufferedDataLength == 0);
00052 MessageAuthenticationCode &mac = AccessMAC();
00053 unsigned int blockSize = mac.TagSize();
00054
00055 mac.TruncatedFinal(m_buffer, macSize);
00056 xorbuf(tag, m_buffer, m_buffer+blockSize, macSize);
00057 }
00058
00059 NAMESPACE_END