byte HotStepper::nextStep(){
byte currentStep = unpad(((byte)*_port), _pinmask);
switch(currentStep){
case B0000:
case B0001:
return (_dir == FORWARD ? B0010 : B1000);
case B0010:
return (_dir == FORWARD ? B0100 : B0001);
case B0100:
return (_dir == FORWARD ? B1000 : B0010);
case B1000:
return (_dir == FORWARD ? B0001 : B0100);
}
}
/* C = C + AB. */
void square_sgemm(int n, float *A, float *B, float *C) {
const int npad = ((n + K_STRIDE - 1) / K_STRIDE) * K_STRIDE;
float *Acpy = calloc(npad * npad, sizeof(float));
transpose(n, npad, A, Acpy);
if (n % K_STRIDE == 0) {
squarepad_sgemm(n, Acpy, B, C);
} else {
float *Bcpy = calloc(npad * npad, sizeof(float));
float *Ccpy = calloc(npad * npad, sizeof(float));
transpose(n, npad, A, Acpy);
pad(n, npad, B, Bcpy);
pad(n, npad, C, Ccpy);
/* Call matrix multiply on padded matrices. */
squarepad_sgemm(npad, Acpy, Bcpy, Ccpy);
unpad(n, npad, Ccpy, C);
free(Bcpy);
free(Ccpy);
}
free(Acpy);
}
/*
* Decode a message
*/
secure_vector<byte> EME::decode(const secure_vector<byte>& msg,
size_t key_bits) const
{
return unpad(msg.data(), msg.size(), key_bits);
}
/*
* Decode a message
*/
secure_vector<byte> EME::decode(const byte msg[], size_t msg_len,
size_t key_bits) const
{
return unpad(msg, msg_len, key_bits);
}
void decrypt_block(uint32_t round_keys[NUM_ROUND_KEYS][ROUND_KEY_LENGTH], uint32_t current_block[BLOCK_LENGTH], uint32_t past_block[BLOCK_LENGTH], char* output, int test) {
int last_byte_loc;
uint32_t next_past_block[BLOCK_LENGTH]; // stores next_block so it can be set to current_block after CBC after decryption
memcpy(next_past_block, current_block, BLOCK_LENGTH * BYTE_CHUNK_SIZE);
/*
* START CODE BLOCK
*
* Following code from serpent.c file in official submission code (http://www.cl.cam.ac.uk/~rja14/Papers/serpent.tar.gz) with minor name changes. See 'sboxes.h' for note on copyright.
*/
register uint32_t x0, x1, x2, x3;
register uint32_t y0, y1, y2, y3;
x0 = current_block[0];
x1 = current_block[1];
x2 = current_block[2];
x3 = current_block[3];
/* Start to decrypt the ciphertext x */
keying(x0, x1, x2, x3, round_keys[32]);
InvRND31(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[31]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND30(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[30]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND29(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[29]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND28(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[28]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND27(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[27]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND26(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[26]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND25(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[25]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND24(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[24]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND23(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[23]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND22(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[22]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND21(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[21]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND20(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[20]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND19(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[19]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND18(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[18]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND17(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[17]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND16(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[16]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND15(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[15]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND14(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[14]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND13(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[13]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND12(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[12]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND11(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[11]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND10(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[10]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND09(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 9]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND08(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 8]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND07(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 7]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND06(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 6]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND05(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 5]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND04(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 4]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND03(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 3]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND02(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 2]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND01(x0, x1, x2, x3, y0, y1, y2, y3);
keying(y0, y1, y2, y3, round_keys[ 1]);
inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
InvRND00(x0, x1, x2, x3, y0, y1, y2, y3);
x0 = y0; x1 = y1; x2 = y2; x3 = y3;
keying(x0, x1, x2, x3, round_keys[ 0]);
/* The plaintext is now in x */
current_block[0] = x0;
current_block[1] = x1;
current_block[2] = x2;
current_block[3] = x3;
/*
* END CODE BLOCK
*/
if (!test) {
decrypt_cbc(current_block, past_block);
}
last_byte_loc = unpad(current_block);
decrypt_export_block(output, current_block, last_byte_loc);
memcpy(past_block, next_past_block, BLOCK_LENGTH * BYTE_CHUNK_SIZE);
}
/*
* Decode a message
*/
SecureVector<byte> EME::decode(const MemoryRegion<byte>& msg,
size_t key_bits) const
{
return unpad(&msg[0], msg.size(), key_bits);
}
