#include "a3a8.h" // must use the 'romdata' to ensure the data is saved in rom /* An implementation of the GSM A3A8 algorithm. (Specifically, COMP128.) */ /* Copyright 1998, Marc Briceno, Ian Goldberg, and David Wagner. * All rights reserved. */ /* These are the COMP128 compression tables */ #pragma pack (1) static const unsigned char table_0[512] = { 0x66, 0xB1, 0xBA, 0xA2, 0x02, 0x9C, 0x70, 0x4B, 0x37, 0x19, 0x08, 0x0C, 0xFB, 0xC1, 0xF6, 0xBC, 0x6D, 0xD5, 0x97, 0x35, 0x2A, 0x4F, 0xBF, 0x73, 0xE9, 0xF2, 0xA4, 0xDF, 0xD1, 0x94, 0x6C, 0xA1, 0xFC, 0x25, 0xF4, 0x2F, 0x40, 0xD3, 0x06, 0xED, 0xB9, 0xA0, 0x8B, 0x71, 0x4C, 0x8A, 0x3B, 0x46, 0x43, 0x1A, 0x0D, 0x9D, 0x3F, 0xB3, 0xDD, 0x1E, 0xD6, 0x24, 0xA6, 0x45, 0x98, 0x7C, 0xCF, 0x74, 0xF7, 0xC2, 0x29, 0x54, 0x47, 0x01, 0x31, 0x0E, 0x5F, 0x23, 0xA9, 0x15, 0x60, 0x4E, 0xD7, 0xE1, 0xB6, 0xF3, 0x1C, 0x5C, 0xC9, 0x76, 0x04, 0x4A, 0xF8, 0x80, 0x11, 0x0B, 0x92, 0x84, 0xF5, 0x30, 0x95, 0x5A, 0x78, 0x27, 0x57, 0xE6, 0x6A, 0xE8, 0xAF, 0x13, 0x7E, 0xBE, 0xCA, 0x8D, 0x89, 0xB0, 0xFA, 0x1B, 0x65, 0x28, 0xDB, 0xE3, 0x3A, 0x14, 0x33, 0xB2, 0x62, 0xD8, 0x8C, 0x16, 0x20, 0x79, 0x3D, 0x67, 0xCB, 0x48, 0x1D, 0x6E, 0x55, 0xD4, 0xB4, 0xCC, 0x96, 0xB7, 0x0F, 0x42, 0xAC, 0xC4, 0x38, 0xC5, 0x9E, 0x00, 0x64, 0x2D, 0x99, 0x07, 0x90, 0xDE, 0xA3, 0xA7, 0x3C, 0x87, 0xD2, 0xE7, 0xAE, 0xA5, 0x26, 0xF9, 0xE0, 0x22, 0xDC, 0xE5, 0xD9, 0xD0, 0xF1, 0x44, 0xCE, 0xBD, 0x7D, 0xFF, 0xEF, 0x36, 0xA8, 0x59, 0x7B, 0x7A, 0x49, 0x91, 0x75, 0xEA, 0x8F, 0x63, 0x81, 0xC8, 0xC0, 0x52, 0x68, 0xAA, 0x88, 0xEB, 0x5D, 0x51, 0xCD, 0xAD, 0xEC, 0x5E, 0x69, 0x34, 0x2E, 0xE4, 0xC6, 0x05, 0x39, 0xFE, 0x61, 0x9B, 0x8E, 0x85, 0xC7, 0xAB, 0xBB, 0x32, 0x41, 0xB5, 0x7F, 0x6B, 0x93, 0xE2, 0xB8, 0xDA, 0x83, 0x21, 0x4D, 0x56, 0x1F, 0x2C, 0x58, 0x3E, 0xEE, 0x12, 0x18, 0x2B, 0x9A, 0x17, 0x50, 0x9F, 0x86, 0x6F, 0x09, 0x72, 0x03, 0x5B, 0x10, 0x82, 0x53, 0x0A, 0xC3, 0xF0, 0xFD, 0x77, 0xB1, 0x66, 0xA2, 0xBA, 0x9C, 0x02, 0x4B, 0x70, 0x19, 0x37, 0x0C, 0x08, 0xC1, 0xFB, 0xBC, 0xF6, 0xD5, 0x6D, 0x35, 0x97, 0x4F, 0x2A, 0x73, 0xBF, 0xF2, 0xE9, 0xDF, 0xA4, 0x94, 0xD1, 0xA1, 0x6C, 0x25, 0xFC, 0x2F, 0xF4, 0xD3, 0x40, 0xED, 0x06, 0xA0, 0xB9, 0x71, 0x8B, 0x8A, 0x4C, 0x46, 0x3B, 0x1A, 0x43, 0x9D, 0x0D, 0xB3, 0x3F, 0x1E, 0xDD, 0x24, 0xD6, 0x45, 0xA6, 0x7C, 0x98, 0x74, 0xCF, 0xC2, 0xF7, 0x54, 0x29, 0x01, 0x47, 0x0E, 0x31, 0x23, 0x5F, 0x15, 0xA9, 0x4E, 0x60, 0xE1, 0xD7, 0xF3, 0xB6, 0x5C, 0x1C, 0x76, 0xC9, 0x4A, 0x04, 0x80, 0xF8, 0x0B, 0x11, 0x84, 0x92, 0x30, 0xF5, 0x5A, 0x95, 0x27, 0x78, 0xE6, 0x57, 0xE8, 0x6A, 0x13, 0xAF, 0xBE, 0x7E, 0x8D, 0xCA, 0xB0, 0x89, 0x1B, 0xFA, 0x28, 0x65, 0xE3, 0xDB, 0x14, 0x3A, 0xB2, 0x33, 0xD8, 0x62, 0x16, 0x8C, 0x79, 0x20, 0x67, 0x3D, 0x48, 0xCB, 0x6E, 0x1D, 0xD4, 0x55, 0xCC, 0xB4, 0xB7, 0x96, 0x42, 0x0F, 0xC4, 0xAC, 0xC5, 0x38, 0x00, 0x9E, 0x2D, 0x64, 0x07, 0x99, 0xDE, 0x90, 0xA7, 0xA3, 0x87, 0x3C, 0xE7, 0xD2, 0xA5, 0xAE, 0xF9, 0x26, 0x22, 0xE0, 0xE5, 0xDC, 0xD0, 0xD9, 0x44, 0xF1, 0xBD, 0xCE, 0xFF, 0x7D, 0x36, 0xEF, 0x59, 0xA8, 0x7A, 0x7B, 0x91, 0x49, 0xEA, 0x75, 0x63, 0x8F, 0xC8, 0x81, 0x52, 0xC0, 0xAA, 0x68, 0xEB, 0x88, 0x51, 0x5D, 0xAD, 0xCD, 0x5E, 0xEC, 0x34, 0x69, 0xE4, 0x2E, 0x05, 0xC6, 0xFE, 0x39, 0x9B, 0x61, 0x85, 0x8E, 0xAB, 0xC7, 0x32, 0xBB, 0xB5, 0x41, 0x6B, 0x7F, 0xE2, 0x93, 0xDA, 0xB8, 0x21, 0x83, 0x56, 0x4D, 0x2C, 0x1F, 0x3E, 0x58, 0x12, 0xEE, 0x2B, 0x18, 0x17, 0x9A, 0x9F, 0x50, 0x6F, 0x86, 0x72, 0x09, 0x5B, 0x03, 0x82, 0x10, 0x0A, 0x53, 0xF0, 0xC3, 0x77, 0xFD }; #pragma pack (1) static const unsigned char table_1[256] = { 0x13, 0x0B, 0x50, 0x72, 0x2B, 0x01, 0x45, 0x5E, 0x27, 0x12, 0x7F, 0x75, 0x61, 0x03, 0x55, 0x2B, 0x1B, 0x7C, 0x46, 0x53, 0x2F, 0x47, 0x3F, 0x0A, 0x2F, 0x59, 0x4F, 0x04, 0x0E, 0x3B, 0x0B, 0x05, 0x23, 0x6B, 0x67, 0x44, 0x15, 0x56, 0x24, 0x5B, 0x55, 0x7E, 0x20, 0x32, 0x6D, 0x5E, 0x78, 0x06, 0x35, 0x4F, 0x1C, 0x2D, 0x63, 0x5F, 0x29, 0x22, 0x58, 0x44, 0x5D, 0x37, 0x6E, 0x7D, 0x69, 0x14, 0x5A, 0x50, 0x4C, 0x60, 0x17, 0x3C, 0x59, 0x40, 0x79, 0x38, 0x0E, 0x4A, 0x65, 0x08, 0x13, 0x4E, 0x4C, 0x42, 0x68, 0x2E, 0x6F, 0x32, 0x20, 0x03, 0x27, 0x00, 0x3A, 0x19, 0x5C, 0x16, 0x12, 0x33, 0x39, 0x41, 0x77, 0x74, 0x16, 0x6D, 0x07, 0x56, 0x3B, 0x5D, 0x3E, 0x6E, 0x4E, 0x63, 0x4D, 0x43, 0x0C, 0x71, 0x57, 0x62, 0x66, 0x05, 0x58, 0x21, 0x26, 0x38, 0x17, 0x08, 0x4B, 0x2D, 0x0D, 0x4B, 0x5F, 0x3F, 0x1C, 0x31, 0x7B, 0x78, 0x14, 0x70, 0x2C, 0x1E, 0x0F, 0x62, 0x6A, 0x02, 0x67, 0x1D, 0x52, 0x6B, 0x2A, 0x7C, 0x18, 0x1E, 0x29, 0x10, 0x6C, 0x64, 0x75, 0x28, 0x49, 0x28, 0x07, 0x72, 0x52, 0x73, 0x24, 0x70, 0x0C, 0x66, 0x64, 0x54, 0x5C, 0x30, 0x48, 0x61, 0x09, 0x36, 0x37, 0x4A, 0x71, 0x7B, 0x11, 0x1A, 0x35, 0x3A, 0x04, 0x09, 0x45, 0x7A, 0x15, 0x76, 0x2A, 0x3C, 0x1B, 0x49, 0x76, 0x7D, 0x22, 0x0F, 0x41, 0x73, 0x54, 0x40, 0x3E, 0x51, 0x46, 0x01, 0x18, 0x6F, 0x79, 0x53, 0x68, 0x51, 0x31, 0x7F, 0x30, 0x69, 0x1F, 0x0A, 0x06, 0x5B, 0x57, 0x25, 0x10, 0x36, 0x74, 0x7E, 0x1F, 0x26, 0x0D, 0x00, 0x48, 0x6A, 0x4D, 0x3D, 0x1A, 0x43, 0x2E, 0x1D, 0x60, 0x25, 0x3D, 0x34, 0x65, 0x11, 0x2C, 0x6C, 0x47, 0x34, 0x42, 0x39, 0x21, 0x33, 0x19, 0x5A, 0x02, 0x77, 0x7A, 0x23 }; #pragma pack (1) static const unsigned char table_2[128] = { 0x34, 0x32, 0x2C, 0x06, 0x15, 0x31, 0x29, 0x3B, 0x27, 0x33, 0x19, 0x20, 0x33, 0x2F, 0x34, 0x2B, 0x25, 0x04, 0x28, 0x22, 0x3D, 0x0C, 0x1C, 0x04, 0x3A, 0x17, 0x08, 0x0F, 0x0C, 0x16, 0x09, 0x12, 0x37, 0x0A, 0x21, 0x23, 0x32, 0x01, 0x2B, 0x03, 0x39, 0x0D, 0x3E, 0x0E, 0x07, 0x2A, 0x2C, 0x3B, 0x3E, 0x39, 0x1B, 0x06, 0x08, 0x1F, 0x1A, 0x36, 0x29, 0x16, 0x2D, 0x14, 0x27, 0x03, 0x10, 0x38, 0x30, 0x02, 0x15, 0x1C, 0x24, 0x2A, 0x3C, 0x21, 0x22, 0x12, 0x00, 0x0B, 0x18, 0x0A, 0x11, 0x3D, 0x1D, 0x0E, 0x2D, 0x1A, 0x37, 0x2E, 0x0B, 0x11, 0x36, 0x2E, 0x09, 0x18, 0x1E, 0x3C, 0x20, 0x00, 0x14, 0x26, 0x02, 0x1E, 0x3A, 0x23, 0x01, 0x10, 0x38, 0x28, 0x17, 0x30, 0x0D, 0x13, 0x13, 0x1B, 0x1F, 0x35, 0x2F, 0x26, 0x3F, 0x0F, 0x31, 0x05, 0x25, 0x35, 0x19, 0x24, 0x3F, 0x1D, 0x05, 0x07 }; #pragma pack (1) static const unsigned char table_3[64] = { 0x01, 0x05, 0x1D, 0x06, 0x19, 0x01, 0x12, 0x17, 0x11, 0x13, 0x00, 0x09, 0x18, 0x19, 0x06, 0x1F, 0x1C, 0x14, 0x18, 0x1E, 0x04, 0x1B, 0x03, 0x0D, 0x0F, 0x10, 0x0E, 0x12, 0x04, 0x03, 0x08, 0x09, 0x14, 0x00, 0x0C, 0x1A, 0x15, 0x08, 0x1C, 0x02, 0x1D, 0x02, 0x0F, 0x07, 0x0B, 0x16, 0x0E, 0x0A, 0x11, 0x15, 0x0C, 0x1E, 0x1A, 0x1B, 0x10, 0x1F, 0x0B, 0x07, 0x0D, 0x17, 0x0A, 0x05, 0x16, 0x13 }; #pragma pack (1) static const unsigned char table_4[32] = { 0x0F, 0x0C, 0x0A, 0x04, 0x01, 0x0E, 0x0B, 0x07, 0x05, 0x00, 0x0E, 0x07, 0x01, 0x02, 0x0D, 0x08, 0x0A, 0x03, 0x04, 0x09, 0x06, 0x00, 0x03, 0x02, 0x05, 0x06, 0x08, 0x09, 0x0B, 0x0D, 0x0F, 0x0C }; // --------------------------------------------------------------------- /* * rand[0..15]: the challenge from the base station * key[0..15]: the SIM's A3/A8 long-term key Ki * simoutput[0..11]: what you'd get back if you fed rand and key to a real * SIM. * * The GSM spec states that simoutput[0..3] is SRES, * and simoutput[4..11] is Kc (the A5 session key). * (See GSM 11.11, Section 8.16. See also the leaked document * referenced below.) * Note that Kc is bits 74..127 of the COMP128 output, followed by 10 * zeros. * In other words, A5 is keyed with only 54 bits of entropy. This * represents a deliberate weakening of the key used for voice privacy * by a factor of over 1000. * * Verified with a Pacific Bell Schlumberger SIM. Your mileage may vary. * * Marc Briceno , Ian Goldberg , * and David Wagner */ /* * This code derived from a leaked document from the GSM standards. * Some missing pieces were filled in by reverse-engineering a working SIM. * We have verified that this is the correct COMP128 algorithm. * * The first page of the document identifies it as * _Technical Information: GSM System Security Study_. * 10-1617-01, 10th June 1988. * The bottom of the title page is marked * Racal Research Ltd. * Worton Drive, Worton Grange Industrial Estate, * Reading, Berks. RG2 0SB, England. * Telephone: Reading (0734) 868601 Telex: 847152 * The relevant bits are in Part I, Section 20 (pages 66--67). Enjoy! * * Note: There are three typos in the spec (discovered by * reverse-engineering). * First, "z = (2 * x[n] + x[n]) mod 2^(9-j)" should clearly read * "z = (2 * x[m] + x[n]) mod 2^(9-j)". * Second, the "k" loop in the "Form bits from bytes" section is severely * botched: the k index should run only from 0 to 3, and clearly the range * on "the (8-k)th bit of byte j" is also off (should be 0..7, not 1..8, * to be consistent with the subsequent section). * Third, SRES is taken from the first 8 nibbles of x[], not the last 8 as * claimed in the document. (And the document doesn't specify how Kc is * derived, but that was also easily discovered with reverse engineering.) * All of these typos have been corrected in the following code. */ void A3A8(/* in */ const unsigned char rand[16], /* in */ const unsigned char key[16], /* out */ unsigned char simoutput[12]) { const unsigned char *table[5]; unsigned char x[32], bits[128]; unsigned i, j, k, l, m, n, y, z, next_bit; table[0] = table_0; table[1] = table_1; table[2] = table_2; table[3] = table_3; table[4] = table_4; /* ( Load RAND into last 16 bytes of input ) */ for (i=16; i<32; i++) x[i] = rand[i-16]; /* ( Loop eight times ) */ for (i=1; i<9; i++) { /* ( Load key into first 16 bytes of input ) */ for (j=0; j<16; j++) x[j] = key[j]; /* ( Perform substitutions ) */ for (j=0; j<5; j++) for (k=0; k<(1<>(3-k)) & 1; /* ( Permutation but not on the last loop ) */ if (i < 8) { for (j=0; j<16; j++) { x[j+16] = 0; for (k=0; k<8; k++) { next_bit = ((8*j + k)*17) & 127; x[j+16] |= bits[next_bit] << (7-k); } } } } /* * ( At this stage the vector x[] consists of 32 nibbles. * The first 8 of these are taken as the output SRES. ) */ /* The remainder of the code is not given explicitly in the * standard, but was derived by reverse-engineering. */ for (i=0; i<4; i++) simoutput[i] = (x[2*i]<<4) | x[2*i+1]; for (i=0; i<6; i++) simoutput[4+i] = (x[2*i+18]<<6) | (x[2*i+18+1]<<2) | (x[2*i+18+2]>>2); simoutput[4+6] = (x[2*6+18]<<6) | (x[2*6+18+1]<<2); simoutput[4+7] = 0; }