diff options
author | lloyd <[email protected]> | 2008-11-08 19:46:52 +0000 |
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committer | lloyd <[email protected]> | 2008-11-08 19:46:52 +0000 |
commit | f1c459725da56fd8ed5766e7779300182fa26bcf (patch) | |
tree | 32295cec92df1155563ae8a535dc695d6800d7f6 /src/stream/salsa20/salsa20.cpp | |
parent | 8dba7b5264403e781bbb86ff61850e4377dca7b9 (diff) |
Split ciphers into block and stream ciphers. Move base class headers
Diffstat (limited to 'src/stream/salsa20/salsa20.cpp')
-rw-r--r-- | src/stream/salsa20/salsa20.cpp | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/src/stream/salsa20/salsa20.cpp b/src/stream/salsa20/salsa20.cpp new file mode 100644 index 000000000..c2c8f289f --- /dev/null +++ b/src/stream/salsa20/salsa20.cpp @@ -0,0 +1,215 @@ +/************************************************* +* Salsa20 Source File * +* (C) 1999-2008 Jack Lloyd * +*************************************************/ + +#include <botan/salsa20.h> +#include <botan/mem_ops.h> +#include <botan/xor_buf.h> +#include <botan/loadstor.h> +#include <botan/parsing.h> + +namespace Botan { + +namespace { + +/************************************************* +* Generate Salsa20 cipher stream * +*************************************************/ +void salsa20(byte output[64], const u32bit input[16]) + { + u32bit x00 = input[0]; + u32bit x01 = input[1]; + u32bit x02 = input[2]; + u32bit x03 = input[3]; + u32bit x04 = input[4]; + u32bit x05 = input[5]; + u32bit x06 = input[6]; + u32bit x07 = input[7]; + u32bit x08 = input[8]; + u32bit x09 = input[9]; + u32bit x10 = input[10]; + u32bit x11 = input[11]; + u32bit x12 = input[12]; + u32bit x13 = input[13]; + u32bit x14 = input[14]; + u32bit x15 = input[15]; + + for(u32bit i = 0; i != 10; ++i) + { + x04 ^= rotate_left(x00 + x12, 7); + x08 ^= rotate_left(x04 + x00, 9); + x12 ^= rotate_left(x08 + x04, 13); + x00 ^= rotate_left(x12 + x08, 18); + x09 ^= rotate_left(x05 + x01, 7); + x13 ^= rotate_left(x09 + x05, 9); + x01 ^= rotate_left(x13 + x09, 13); + x05 ^= rotate_left(x01 + x13, 18); + x14 ^= rotate_left(x10 + x06, 7); + x02 ^= rotate_left(x14 + x10, 9); + x06 ^= rotate_left(x02 + x14, 13); + x10 ^= rotate_left(x06 + x02, 18); + x03 ^= rotate_left(x15 + x11, 7); + x07 ^= rotate_left(x03 + x15, 9); + x11 ^= rotate_left(x07 + x03, 13); + x15 ^= rotate_left(x11 + x07, 18); + + x01 ^= rotate_left(x00 + x03, 7); + x02 ^= rotate_left(x01 + x00, 9); + x03 ^= rotate_left(x02 + x01, 13); + x00 ^= rotate_left(x03 + x02, 18); + x06 ^= rotate_left(x05 + x04, 7); + x07 ^= rotate_left(x06 + x05, 9); + x04 ^= rotate_left(x07 + x06, 13); + x05 ^= rotate_left(x04 + x07, 18); + x11 ^= rotate_left(x10 + x09, 7); + x08 ^= rotate_left(x11 + x10, 9); + x09 ^= rotate_left(x08 + x11, 13); + x10 ^= rotate_left(x09 + x08, 18); + x12 ^= rotate_left(x15 + x14, 7); + x13 ^= rotate_left(x12 + x15, 9); + x14 ^= rotate_left(x13 + x12, 13); + x15 ^= rotate_left(x14 + x13, 18); + } + + store_le(x00 + input[ 0], output + 4 * 0); + store_le(x01 + input[ 1], output + 4 * 1); + store_le(x02 + input[ 2], output + 4 * 2); + store_le(x03 + input[ 3], output + 4 * 3); + store_le(x04 + input[ 4], output + 4 * 4); + store_le(x05 + input[ 5], output + 4 * 5); + store_le(x06 + input[ 6], output + 4 * 6); + store_le(x07 + input[ 7], output + 4 * 7); + store_le(x08 + input[ 8], output + 4 * 8); + store_le(x09 + input[ 9], output + 4 * 9); + store_le(x10 + input[10], output + 4 * 10); + store_le(x11 + input[11], output + 4 * 11); + store_le(x12 + input[12], output + 4 * 12); + store_le(x13 + input[13], output + 4 * 13); + store_le(x14 + input[14], output + 4 * 14); + store_le(x15 + input[15], output + 4 * 15); + } + +} + +/************************************************* +* Combine cipher stream with message * +*************************************************/ +void Salsa20::cipher(const byte in[], byte out[], u32bit length) + { + while(length >= buffer.size() - position) + { + xor_buf(out, in, buffer.begin() + position, buffer.size() - position); + length -= (buffer.size() - position); + in += (buffer.size() - position); + out += (buffer.size() - position); + salsa20(buffer.begin(), state); + + ++state[8]; + if(!state[8]) // if overflow in state[8] + ++state[9]; // carry to state[9] + + position = 0; + } + + xor_buf(out, in, buffer.begin() + position, length); + + position += length; + } + +/************************************************* +* Salsa20 Key Schedule * +*************************************************/ +void Salsa20::key(const byte key[], u32bit length) + { + static const u32bit TAU[] = + { 0x61707865, 0x3120646e, 0x79622d36, 0x6b206574 }; + + static const u32bit SIGMA[] = + { 0x61707865, 0x3320646e, 0x79622d32, 0x6b206574 }; + + clear(); + + if(length == 16) + { + state[0] = TAU[0]; + state[1] = load_le<u32bit>(key, 0); + state[2] = load_le<u32bit>(key, 1); + state[3] = load_le<u32bit>(key, 2); + state[4] = load_le<u32bit>(key, 3); + state[5] = TAU[1]; + state[10] = TAU[2]; + state[11] = load_le<u32bit>(key, 0); + state[12] = load_le<u32bit>(key, 1); + state[13] = load_le<u32bit>(key, 2); + state[14] = load_le<u32bit>(key, 3); + state[15] = TAU[3]; + } + else if(length == 32) + { + state[0] = SIGMA[0]; + state[1] = load_le<u32bit>(key, 0); + state[2] = load_le<u32bit>(key, 1); + state[3] = load_le<u32bit>(key, 2); + state[4] = load_le<u32bit>(key, 3); + state[5] = SIGMA[1]; + state[10] = SIGMA[2]; + state[11] = load_le<u32bit>(key, 4); + state[12] = load_le<u32bit>(key, 5); + state[13] = load_le<u32bit>(key, 6); + state[14] = load_le<u32bit>(key, 7); + state[15] = SIGMA[3]; + } + + const byte ZERO[8] = { 0 }; + resync(ZERO, sizeof(ZERO)); + } + +/************************************************* +* Return the name of this type * +*************************************************/ +void Salsa20::resync(const byte iv[], u32bit length) + { + if(length != IV_LENGTH) + throw Invalid_IV_Length(name(), length); + + state[6] = load_le<u32bit>(iv, 0); + state[7] = load_le<u32bit>(iv, 1); + state[8] = 0; + state[9] = 0; + + salsa20(buffer.begin(), state); + ++state[8]; + if(!state[8]) // if overflow in state[8] + ++state[9]; // carry to state[9] + + position = 0; + } + +/************************************************* +* Return the name of this type * +*************************************************/ +std::string Salsa20::name() const + { + return "Salsa20"; + } + +/************************************************* +* Clear memory of sensitive data * +*************************************************/ +void Salsa20::clear() throw() + { + state.clear(); + buffer.clear(); + position = 0; + } + +/************************************************* +* Salsa20 Constructor * +*************************************************/ +Salsa20::Salsa20() : StreamCipher(16, 32, 16, 8) + { + clear(); + } + +} |