diff options
Diffstat (limited to 'src/lib')
| -rw-r--r-- | src/lib/modes/cbc/cbc.cpp | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/src/lib/modes/cbc/cbc.cpp b/src/lib/modes/cbc/cbc.cpp index 3095875f5..5fe5c8b17 100644 --- a/src/lib/modes/cbc/cbc.cpp +++ b/src/lib/modes/cbc/cbc.cpp @@ -99,15 +99,15 @@ void CBC_Encryption::update(secure_vector<byte>& buffer, size_t offset) BOTAN_ASSERT(sz % BS == 0, "CBC input is full blocks"); const size_t blocks = sz / BS; + const byte* prev_block = state_ptr(); + if(blocks) { - xor_buf(&buf[0], state_ptr(), BS); - cipher().encrypt(&buf[0]); - - for(size_t i = 1; i != blocks; ++i) + for(size_t i = 0; i != blocks; ++i) { - xor_buf(&buf[BS*i], &buf[BS*(i-1)], BS); + xor_buf(&buf[BS*i], prev_block, BS); cipher().encrypt(&buf[BS*i]); + prev_block = &buf[BS*i]; } state().assign(&buf[BS*(blocks-1)], &buf[BS*blocks]); @@ -267,6 +267,7 @@ void CTS_Decryption::finish(secure_vector<byte>& buffer, size_t offset) if(sz % BS == 0) { // swap last two blocks + for(size_t i = 0; i != BS; ++i) std::swap(buffer[buffer.size()-BS+i], buffer[buffer.size()-2*BS+i]); @@ -283,21 +284,17 @@ void CTS_Decryption::finish(secure_vector<byte>& buffer, size_t offset) update(buffer, offset); cipher().decrypt(&last[0]); + xor_buf(&last[0], &last[BS], final_bytes - BS); for(size_t i = 0; i != final_bytes - BS; ++i) - { - last[i] ^= last[i + BS]; - last[i + BS] ^= last[i]; - last[i] ^= last[i + BS]; - } + std::swap(last[i], last[i + BS]); cipher().decrypt(&last[0]); xor_buf(&last[0], state_ptr(), BS); buffer += last; } - } } |