| rs = (0xee,0xa6,0xa7,0x25,0x1c,0x1e,0x72,0x91 |
| ,0x6d,0x11,0xc2,0xcb,0x21,0x4d,0x3c,0x25 |
| ,0x25,0x39,0x12,0x1d,0x8e,0x23,0x4e,0x65 |
| ,0x2d,0x65,0x1f,0xa4,0xc8,0xcf,0xf8,0x80) |
| |
| msg = (0x8e,0x99,0x3b,0x9f,0x48,0x68,0x12,0x73 |
| ,0xc2,0x96,0x50,0xba,0x32,0xfc,0x76,0xce |
| ,0x48,0x33,0x2e,0xa7,0x16,0x4d,0x96,0xa4 |
| ,0x47,0x6f,0xb8,0xc5,0x31,0xa1,0x18,0x6a |
| ,0xc0,0xdf,0xc1,0x7c,0x98,0xdc,0xe8,0x7b |
| ,0x4d,0xa7,0xf0,0x11,0xec,0x48,0xc9,0x72 |
| ,0x71,0xd2,0xc2,0x0f,0x9b,0x92,0x8f,0xe2 |
| ,0x27,0x0d,0x6f,0xb8,0x63,0xd5,0x17,0x38 |
| ,0xb4,0x8e,0xee,0xe3,0x14,0xa7,0xcc,0x8a |
| ,0xb9,0x32,0x16,0x45,0x48,0xe5,0x26,0xae |
| ,0x90,0x22,0x43,0x68,0x51,0x7a,0xcf,0xea |
| ,0xbd,0x6b,0xb3,0x73,0x2b,0xc0,0xe9,0xda |
| ,0x99,0x83,0x2b,0x61,0xca,0x01,0xb6,0xde |
| ,0x56,0x24,0x4a,0x9e,0x88,0xd5,0xf9,0xb3 |
| ,0x79,0x73,0xf6,0x22,0xa4,0x3d,0x14,0xa6 |
| ,0x59,0x9b,0x1f,0x65,0x4c,0xb4,0x5a,0x74 |
| ,0xe3,0x55,0xa5) |
| |
| tag = (0xf3,0xff,0xc7,0x70,0x3f,0x94,0x00,0xe5 |
| ,0x2a,0x7d,0xfb,0x4b,0x3d,0x33,0x05,0xd9) |
| |
| print len(msg) |
| |
| WORD = 0xffffffff |
| |
| def add(x, y): |
| u = 0 |
| r = [0] * 17 |
| for i in range(17): |
| u += (x[i] + y[i]) & WORD |
| r[i] = u & 0xff |
| u >>= 8 |
| return r |
| |
| def reduce(x): |
| r = list(x) |
| u = 0 |
| |
| for i in range(16): |
| u += r[i] |
| r[i] = u & 0xff |
| u >>= 8 |
| u += r[16] |
| r[16] = u & 3 |
| u = 5 * (u >> 2) |
| |
| for i in range(16): |
| u += r[i] |
| r[i] = u & 0xff |
| u >>= 8 |
| u += r[16] |
| r[16] = u |
| |
| return r |
| |
| def modmul(x, y): |
| r = [0] * 17 |
| for i in range(17): |
| u = 0 |
| for j in range(i + 1): |
| u += (x[j] * y[i - j]) & WORD |
| for j in range(i + 1, 17): |
| u += (320 * x[j] * y[i + 17 - j]) & WORD |
| r[i] = u |
| return reduce(r) |
| |
| def dump(why, v): |
| print '%s = %s' % (why, ' '.join('%08x' % x for x in v)) |
| |
| def freeze(x): |
| # -2^130 - 5 in twos complement |
| negative_130_5 = (5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 252) |
| |
| r = add(x, negative_130_5) |
| dump('minusp', r) |
| negative = bool(x[16] >> 7) |
| if negative: |
| return r |
| else: |
| return x |
| |
| def poly1305(msg, rs): |
| r, s = list(rs[:16]), list(rs[16:]) |
| |
| r[3] &= 15 |
| r[4] &= 252 |
| r[7] &= 15 |
| r[8] &= 252 |
| r[11] &= 15 |
| r[12] &= 252 |
| r[15] &= 15 |
| r.append(0) |
| |
| h = [0] * 17 |
| dump('r-init', r) |
| dump('h-init', h) |
| |
| block = 0 |
| |
| for offs in range(0, len(msg), 16): |
| print '--- block %d ---' % block |
| block += 1 |
| c = list(msg[offs:offs+16]) |
| c.append(1) |
| while len(c) != 17: c.append(0) |
| dump('c', c) |
| |
| h = add(h, c) |
| dump('after-add', h) |
| h = modmul(h, r) |
| dump('after-mul', h) |
| |
| dump('end-block', h) |
| h = freeze(h) |
| dump('h', h) |
| s.append(0) |
| h = add(h, s) |
| dump('final', h) |
| return h[:16] |
| |
| r = poly1305(msg, rs) |
| print repr([hex(x) for x in r]) |
