diff options
| -rw-r--r-- | A5.1/C/calculate_chain.c | 167 |
1 files changed, 8 insertions, 159 deletions
diff --git a/A5.1/C/calculate_chain.c b/A5.1/C/calculate_chain.c index 23361a3..a7d3266 100644 --- a/A5.1/C/calculate_chain.c +++ b/A5.1/C/calculate_chain.c @@ -127,6 +127,7 @@ typedef word bit; /* Calculate the parity of a 32-bit word, i.e. the sum of its bits modulo 2 */ bit parity(word x) { + // x ^= x>>32; x ^= x>>16; x ^= x>>8; x ^= x>>4; @@ -152,7 +153,7 @@ word R1, R2, R3; * return the majority value of those 3 bits. */ bit majority() { int sum; - sum = parity(R1&R1MID) + parity(R2&R2MID) + parity(R3&R3MID); + sum = ((R1&R1MID) >> 8) + ((R2&R2MID) >> 10) + ((R3&R3MID) >> 10); if (sum >= 2) return 1; else @@ -173,169 +174,16 @@ inline void clock() { R3 = clockone(R3, R3MASK, R3TAPS); } -/* Clock all three of R1,R2,R3, ignoring their middle bits. - * This is only used for key setup. */ -void clockallthree() { - R1 = clockone(R1, R1MASK, R1TAPS); - R2 = clockone(R2, R2MASK, R2TAPS); - R3 = clockone(R3, R3MASK, R3TAPS); -} - /* Generate an output bit from the current state. * You grab a bit from each register via the output generation taps; * then you XOR the resulting three bits. */ bit getbit() { - return parity(R1&R1OUT)^parity(R2&R2OUT)^parity(R3&R3OUT); -} - -/* Do the A5/1 key setup. This routine accepts a 64-bit key and - * a 22-bit frame number. */ -void keysetup(byte key[8], word frame) { - int i; - bit keybit, framebit; - - /* Zero out the shift registers. */ - R1 = R2 = R3 = 0; - - /* Load the key into the shift registers, - * LSB of first byte of key array first, - * clocking each register once for every - * key bit loaded. (The usual clock - * control rule is temporarily disabled.) */ - for (i=0; i<64; i++) { - clockallthree(); /* always clock */ - keybit = (key[i/8] >> (i&7)) & 1; /* The i-th bit of the key */ - R1 ^= keybit; R2 ^= keybit; R3 ^= keybit; - } - - /* Load the frame number into the shift - * registers, LSB first, - * clocking each register once for every - * key bit loaded. (The usual clock - * control rule is still disabled.) */ - for (i=0; i<22; i++) { - clockallthree(); /* always clock */ - framebit = (frame >> i) & 1; /* The i-th bit of the frame # */ - R1 ^= framebit; R2 ^= framebit; R3 ^= framebit; - } - - /* Run the shift registers for 100 clocks - * to mix the keying material and frame number - * together with output generation disabled, - * so that there is sufficient avalanche. - * We re-enable the majority-based clock control - * rule from now on. */ - for (i=0; i<100; i++) { - clock(); - } - - /* Now the key is properly set up. */ -} - -/* Generate output. We generate 228 bits of - * keystream output. The first 114 bits is for - * the A->B frame; the next 114 bits is for the - * B->A frame. You allocate a 15-byte buffer - * for each direction, and this function fills - * it in. */ -void run(byte AtoBkeystream[], byte BtoAkeystream[]) { - int i; - - /* Zero out the output buffers. */ - for (i=0; i<=113/8; i++) - AtoBkeystream[i] = BtoAkeystream[i] = 0; - - /* Generate 114 bits of keystream for the - * A->B direction. Store it, MSB first. */ - for (i=0; i<114; i++) { - clock(); - AtoBkeystream[i/8] |= getbit() << (7-(i&7)); - } - - /* Generate 114 bits of keystream for the - * B->A direction. Store it, MSB first. */ - for (i=0; i<114; i++) { - clock(); - BtoAkeystream[i/8] |= getbit() << (7-(i&7)); - } -} - -/* Test the code by comparing it against - * a known-good test vector. */ -void test() { - byte key[8] = {0x12, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF}; - word frame = 0x134; - byte goodAtoB[15] = { 0x53, 0x4E, 0xAA, 0x58, 0x2F, 0xE8, 0x15, - 0x1A, 0xB6, 0xE1, 0x85, 0x5A, 0x72, 0x8C, 0x00 }; - byte goodBtoA[15] = { 0x24, 0xFD, 0x35, 0xA3, 0x5D, 0x5F, 0xB6, - 0x52, 0x6D, 0x32, 0xF9, 0x06, 0xDF, 0x1A, 0xC0 }; - byte AtoB[15], BtoA[15]; - int i, failed=0; - - keysetup(key, frame); - run(AtoB, BtoA); - - /* Compare against the test vector. */ - for (i=0; i<15; i++) - if (AtoB[i] != goodAtoB[i]) - failed = 1; - for (i=0; i<15; i++) - if (BtoA[i] != goodBtoA[i]) - failed = 1; - - /* Print some debugging output. */ - printf("key: 0x"); - for (i=0; i<8; i++) - printf("%02X", key[i]); - printf("\n"); - printf("frame number: 0x%06X\n", (unsigned int)frame); - printf("known good output:\n"); - printf(" A->B: 0x"); - for (i=0; i<15; i++) - printf("%02X", goodAtoB[i]); - printf(" B->A: 0x"); - for (i=0; i<15; i++) - printf("%02X", goodBtoA[i]); - printf("\n"); - printf("observed output:\n"); - printf(" A->B: 0x"); - for (i=0; i<15; i++) - printf("%02X", AtoB[i]); - printf(" B->A: 0x"); - for (i=0; i<15; i++) - printf("%02X", BtoA[i]); - printf("\n"); - - if (!failed) { - printf("Self-check succeeded: everything looks ok.\n"); - return; - } else { - /* Problems! The test vectors didn't compare*/ - printf("\nI don't know why this broke; contact the authors.\n"); - exit(1); - } -} - -word bin2hex (char *string) -{ - int i; - word res = 0; - int length; - - length = strlen (string); - - for (i = 0; i < length; i++) - { - res = res << 1; - if (string[0] == '1') res += 1; - string++; - } - return res; - + // return parity(R1&R1OUT)^parity(R2&R2OUT)^parity(R3&R3OUT); + return ((R1&R1OUT) >> 18) ^ ((R2&R2OUT) >> 21) ^ ((R3&R3OUT) >> 22); } inline word calculate_link (word input, word count) { - word result=0; + word result; int i; input ^= count ^ (count << 23) ^ (count << (22 + 23)); @@ -344,9 +192,10 @@ inline word calculate_link (word input, word count) { R2 = (input >> 23) & R2MASK; R3 = input & R3MASK; - for(i=0;i<64;i++) { - result = (result << 1)| getbit(); + result = getbit(); + for(i=1;i<64;i++) { clock(); + result = (result << 1)| getbit(); } return result; } |