|  | /* gf128mul.c - GF(2^128) multiplication functions | 
|  | * | 
|  | * Copyright (c) 2003, Dr Brian Gladman, Worcester, UK. | 
|  | * Copyright (c) 2006, Rik Snel <rsnel@cube.dyndns.org> | 
|  | * | 
|  | * Based on Dr Brian Gladman's (GPL'd) work published at | 
|  | * http://gladman.plushost.co.uk/oldsite/cryptography_technology/index.php | 
|  | * See the original copyright notice below. | 
|  | * | 
|  | * This program is free software; you can redistribute it and/or modify it | 
|  | * under the terms of the GNU General Public License as published by the Free | 
|  | * Software Foundation; either version 2 of the License, or (at your option) | 
|  | * any later version. | 
|  | */ | 
|  |  | 
|  | /* | 
|  | --------------------------------------------------------------------------- | 
|  | Copyright (c) 2003, Dr Brian Gladman, Worcester, UK.   All rights reserved. | 
|  |  | 
|  | LICENSE TERMS | 
|  |  | 
|  | The free distribution and use of this software in both source and binary | 
|  | form is allowed (with or without changes) provided that: | 
|  |  | 
|  | 1. distributions of this source code include the above copyright | 
|  | notice, this list of conditions and the following disclaimer; | 
|  |  | 
|  | 2. distributions in binary form include the above copyright | 
|  | notice, this list of conditions and the following disclaimer | 
|  | in the documentation and/or other associated materials; | 
|  |  | 
|  | 3. the copyright holder's name is not used to endorse products | 
|  | built using this software without specific written permission. | 
|  |  | 
|  | ALTERNATIVELY, provided that this notice is retained in full, this product | 
|  | may be distributed under the terms of the GNU General Public License (GPL), | 
|  | in which case the provisions of the GPL apply INSTEAD OF those given above. | 
|  |  | 
|  | DISCLAIMER | 
|  |  | 
|  | This software is provided 'as is' with no explicit or implied warranties | 
|  | in respect of its properties, including, but not limited to, correctness | 
|  | and/or fitness for purpose. | 
|  | --------------------------------------------------------------------------- | 
|  | Issue 31/01/2006 | 
|  |  | 
|  | This file provides fast multiplication in GF(128) as required by several | 
|  | cryptographic authentication modes | 
|  | */ | 
|  |  | 
|  | #include <crypto/gf128mul.h> | 
|  | #include <linux/kernel.h> | 
|  | #include <linux/module.h> | 
|  | #include <linux/slab.h> | 
|  |  | 
|  | #define gf128mul_dat(q) { \ | 
|  | q(0x00), q(0x01), q(0x02), q(0x03), q(0x04), q(0x05), q(0x06), q(0x07),\ | 
|  | q(0x08), q(0x09), q(0x0a), q(0x0b), q(0x0c), q(0x0d), q(0x0e), q(0x0f),\ | 
|  | q(0x10), q(0x11), q(0x12), q(0x13), q(0x14), q(0x15), q(0x16), q(0x17),\ | 
|  | q(0x18), q(0x19), q(0x1a), q(0x1b), q(0x1c), q(0x1d), q(0x1e), q(0x1f),\ | 
|  | q(0x20), q(0x21), q(0x22), q(0x23), q(0x24), q(0x25), q(0x26), q(0x27),\ | 
|  | q(0x28), q(0x29), q(0x2a), q(0x2b), q(0x2c), q(0x2d), q(0x2e), q(0x2f),\ | 
|  | q(0x30), q(0x31), q(0x32), q(0x33), q(0x34), q(0x35), q(0x36), q(0x37),\ | 
|  | q(0x38), q(0x39), q(0x3a), q(0x3b), q(0x3c), q(0x3d), q(0x3e), q(0x3f),\ | 
|  | q(0x40), q(0x41), q(0x42), q(0x43), q(0x44), q(0x45), q(0x46), q(0x47),\ | 
|  | q(0x48), q(0x49), q(0x4a), q(0x4b), q(0x4c), q(0x4d), q(0x4e), q(0x4f),\ | 
|  | q(0x50), q(0x51), q(0x52), q(0x53), q(0x54), q(0x55), q(0x56), q(0x57),\ | 
|  | q(0x58), q(0x59), q(0x5a), q(0x5b), q(0x5c), q(0x5d), q(0x5e), q(0x5f),\ | 
|  | q(0x60), q(0x61), q(0x62), q(0x63), q(0x64), q(0x65), q(0x66), q(0x67),\ | 
|  | q(0x68), q(0x69), q(0x6a), q(0x6b), q(0x6c), q(0x6d), q(0x6e), q(0x6f),\ | 
|  | q(0x70), q(0x71), q(0x72), q(0x73), q(0x74), q(0x75), q(0x76), q(0x77),\ | 
|  | q(0x78), q(0x79), q(0x7a), q(0x7b), q(0x7c), q(0x7d), q(0x7e), q(0x7f),\ | 
|  | q(0x80), q(0x81), q(0x82), q(0x83), q(0x84), q(0x85), q(0x86), q(0x87),\ | 
|  | q(0x88), q(0x89), q(0x8a), q(0x8b), q(0x8c), q(0x8d), q(0x8e), q(0x8f),\ | 
|  | q(0x90), q(0x91), q(0x92), q(0x93), q(0x94), q(0x95), q(0x96), q(0x97),\ | 
|  | q(0x98), q(0x99), q(0x9a), q(0x9b), q(0x9c), q(0x9d), q(0x9e), q(0x9f),\ | 
|  | q(0xa0), q(0xa1), q(0xa2), q(0xa3), q(0xa4), q(0xa5), q(0xa6), q(0xa7),\ | 
|  | q(0xa8), q(0xa9), q(0xaa), q(0xab), q(0xac), q(0xad), q(0xae), q(0xaf),\ | 
|  | q(0xb0), q(0xb1), q(0xb2), q(0xb3), q(0xb4), q(0xb5), q(0xb6), q(0xb7),\ | 
|  | q(0xb8), q(0xb9), q(0xba), q(0xbb), q(0xbc), q(0xbd), q(0xbe), q(0xbf),\ | 
|  | q(0xc0), q(0xc1), q(0xc2), q(0xc3), q(0xc4), q(0xc5), q(0xc6), q(0xc7),\ | 
|  | q(0xc8), q(0xc9), q(0xca), q(0xcb), q(0xcc), q(0xcd), q(0xce), q(0xcf),\ | 
|  | q(0xd0), q(0xd1), q(0xd2), q(0xd3), q(0xd4), q(0xd5), q(0xd6), q(0xd7),\ | 
|  | q(0xd8), q(0xd9), q(0xda), q(0xdb), q(0xdc), q(0xdd), q(0xde), q(0xdf),\ | 
|  | q(0xe0), q(0xe1), q(0xe2), q(0xe3), q(0xe4), q(0xe5), q(0xe6), q(0xe7),\ | 
|  | q(0xe8), q(0xe9), q(0xea), q(0xeb), q(0xec), q(0xed), q(0xee), q(0xef),\ | 
|  | q(0xf0), q(0xf1), q(0xf2), q(0xf3), q(0xf4), q(0xf5), q(0xf6), q(0xf7),\ | 
|  | q(0xf8), q(0xf9), q(0xfa), q(0xfb), q(0xfc), q(0xfd), q(0xfe), q(0xff) \ | 
|  | } | 
|  |  | 
|  | /*	Given the value i in 0..255 as the byte overflow when a field element | 
|  | in GHASH is multipled by x^8, this function will return the values that | 
|  | are generated in the lo 16-bit word of the field value by applying the | 
|  | modular polynomial. The values lo_byte and hi_byte are returned via the | 
|  | macro xp_fun(lo_byte, hi_byte) so that the values can be assembled into | 
|  | memory as required by a suitable definition of this macro operating on | 
|  | the table above | 
|  | */ | 
|  |  | 
|  | #define xx(p, q)	0x##p##q | 
|  |  | 
|  | #define xda_bbe(i) ( \ | 
|  | (i & 0x80 ? xx(43, 80) : 0) ^ (i & 0x40 ? xx(21, c0) : 0) ^ \ | 
|  | (i & 0x20 ? xx(10, e0) : 0) ^ (i & 0x10 ? xx(08, 70) : 0) ^ \ | 
|  | (i & 0x08 ? xx(04, 38) : 0) ^ (i & 0x04 ? xx(02, 1c) : 0) ^ \ | 
|  | (i & 0x02 ? xx(01, 0e) : 0) ^ (i & 0x01 ? xx(00, 87) : 0) \ | 
|  | ) | 
|  |  | 
|  | #define xda_lle(i) ( \ | 
|  | (i & 0x80 ? xx(e1, 00) : 0) ^ (i & 0x40 ? xx(70, 80) : 0) ^ \ | 
|  | (i & 0x20 ? xx(38, 40) : 0) ^ (i & 0x10 ? xx(1c, 20) : 0) ^ \ | 
|  | (i & 0x08 ? xx(0e, 10) : 0) ^ (i & 0x04 ? xx(07, 08) : 0) ^ \ | 
|  | (i & 0x02 ? xx(03, 84) : 0) ^ (i & 0x01 ? xx(01, c2) : 0) \ | 
|  | ) | 
|  |  | 
|  | static const u16 gf128mul_table_lle[256] = gf128mul_dat(xda_lle); | 
|  | static const u16 gf128mul_table_bbe[256] = gf128mul_dat(xda_bbe); | 
|  |  | 
|  | /* These functions multiply a field element by x, by x^4 and by x^8 | 
|  | * in the polynomial field representation. It uses 32-bit word operations | 
|  | * to gain speed but compensates for machine endianess and hence works | 
|  | * correctly on both styles of machine. | 
|  | */ | 
|  |  | 
|  | static void gf128mul_x_lle(be128 *r, const be128 *x) | 
|  | { | 
|  | u64 a = be64_to_cpu(x->a); | 
|  | u64 b = be64_to_cpu(x->b); | 
|  | u64 _tt = gf128mul_table_lle[(b << 7) & 0xff]; | 
|  |  | 
|  | r->b = cpu_to_be64((b >> 1) | (a << 63)); | 
|  | r->a = cpu_to_be64((a >> 1) ^ (_tt << 48)); | 
|  | } | 
|  |  | 
|  | static void gf128mul_x_bbe(be128 *r, const be128 *x) | 
|  | { | 
|  | u64 a = be64_to_cpu(x->a); | 
|  | u64 b = be64_to_cpu(x->b); | 
|  | u64 _tt = gf128mul_table_bbe[a >> 63]; | 
|  |  | 
|  | r->a = cpu_to_be64((a << 1) | (b >> 63)); | 
|  | r->b = cpu_to_be64((b << 1) ^ _tt); | 
|  | } | 
|  |  | 
|  | void gf128mul_x_ble(be128 *r, const be128 *x) | 
|  | { | 
|  | u64 a = le64_to_cpu(x->a); | 
|  | u64 b = le64_to_cpu(x->b); | 
|  | u64 _tt = gf128mul_table_bbe[b >> 63]; | 
|  |  | 
|  | r->a = cpu_to_le64((a << 1) ^ _tt); | 
|  | r->b = cpu_to_le64((b << 1) | (a >> 63)); | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_x_ble); | 
|  |  | 
|  | static void gf128mul_x8_lle(be128 *x) | 
|  | { | 
|  | u64 a = be64_to_cpu(x->a); | 
|  | u64 b = be64_to_cpu(x->b); | 
|  | u64 _tt = gf128mul_table_lle[b & 0xff]; | 
|  |  | 
|  | x->b = cpu_to_be64((b >> 8) | (a << 56)); | 
|  | x->a = cpu_to_be64((a >> 8) ^ (_tt << 48)); | 
|  | } | 
|  |  | 
|  | static void gf128mul_x8_bbe(be128 *x) | 
|  | { | 
|  | u64 a = be64_to_cpu(x->a); | 
|  | u64 b = be64_to_cpu(x->b); | 
|  | u64 _tt = gf128mul_table_bbe[a >> 56]; | 
|  |  | 
|  | x->a = cpu_to_be64((a << 8) | (b >> 56)); | 
|  | x->b = cpu_to_be64((b << 8) ^ _tt); | 
|  | } | 
|  |  | 
|  | void gf128mul_lle(be128 *r, const be128 *b) | 
|  | { | 
|  | be128 p[8]; | 
|  | int i; | 
|  |  | 
|  | p[0] = *r; | 
|  | for (i = 0; i < 7; ++i) | 
|  | gf128mul_x_lle(&p[i + 1], &p[i]); | 
|  |  | 
|  | memset(r, 0, sizeof(r)); | 
|  | for (i = 0;;) { | 
|  | u8 ch = ((u8 *)b)[15 - i]; | 
|  |  | 
|  | if (ch & 0x80) | 
|  | be128_xor(r, r, &p[0]); | 
|  | if (ch & 0x40) | 
|  | be128_xor(r, r, &p[1]); | 
|  | if (ch & 0x20) | 
|  | be128_xor(r, r, &p[2]); | 
|  | if (ch & 0x10) | 
|  | be128_xor(r, r, &p[3]); | 
|  | if (ch & 0x08) | 
|  | be128_xor(r, r, &p[4]); | 
|  | if (ch & 0x04) | 
|  | be128_xor(r, r, &p[5]); | 
|  | if (ch & 0x02) | 
|  | be128_xor(r, r, &p[6]); | 
|  | if (ch & 0x01) | 
|  | be128_xor(r, r, &p[7]); | 
|  |  | 
|  | if (++i >= 16) | 
|  | break; | 
|  |  | 
|  | gf128mul_x8_lle(r); | 
|  | } | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_lle); | 
|  |  | 
|  | void gf128mul_bbe(be128 *r, const be128 *b) | 
|  | { | 
|  | be128 p[8]; | 
|  | int i; | 
|  |  | 
|  | p[0] = *r; | 
|  | for (i = 0; i < 7; ++i) | 
|  | gf128mul_x_bbe(&p[i + 1], &p[i]); | 
|  |  | 
|  | memset(r, 0, sizeof(r)); | 
|  | for (i = 0;;) { | 
|  | u8 ch = ((u8 *)b)[i]; | 
|  |  | 
|  | if (ch & 0x80) | 
|  | be128_xor(r, r, &p[7]); | 
|  | if (ch & 0x40) | 
|  | be128_xor(r, r, &p[6]); | 
|  | if (ch & 0x20) | 
|  | be128_xor(r, r, &p[5]); | 
|  | if (ch & 0x10) | 
|  | be128_xor(r, r, &p[4]); | 
|  | if (ch & 0x08) | 
|  | be128_xor(r, r, &p[3]); | 
|  | if (ch & 0x04) | 
|  | be128_xor(r, r, &p[2]); | 
|  | if (ch & 0x02) | 
|  | be128_xor(r, r, &p[1]); | 
|  | if (ch & 0x01) | 
|  | be128_xor(r, r, &p[0]); | 
|  |  | 
|  | if (++i >= 16) | 
|  | break; | 
|  |  | 
|  | gf128mul_x8_bbe(r); | 
|  | } | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_bbe); | 
|  |  | 
|  | /*      This version uses 64k bytes of table space. | 
|  | A 16 byte buffer has to be multiplied by a 16 byte key | 
|  | value in GF(128).  If we consider a GF(128) value in | 
|  | the buffer's lowest byte, we can construct a table of | 
|  | the 256 16 byte values that result from the 256 values | 
|  | of this byte.  This requires 4096 bytes. But we also | 
|  | need tables for each of the 16 higher bytes in the | 
|  | buffer as well, which makes 64 kbytes in total. | 
|  | */ | 
|  | /* additional explanation | 
|  | * t[0][BYTE] contains g*BYTE | 
|  | * t[1][BYTE] contains g*x^8*BYTE | 
|  | *  .. | 
|  | * t[15][BYTE] contains g*x^120*BYTE */ | 
|  | struct gf128mul_64k *gf128mul_init_64k_lle(const be128 *g) | 
|  | { | 
|  | struct gf128mul_64k *t; | 
|  | int i, j, k; | 
|  |  | 
|  | t = kzalloc(sizeof(*t), GFP_KERNEL); | 
|  | if (!t) | 
|  | goto out; | 
|  |  | 
|  | for (i = 0; i < 16; i++) { | 
|  | t->t[i] = kzalloc(sizeof(*t->t[i]), GFP_KERNEL); | 
|  | if (!t->t[i]) { | 
|  | gf128mul_free_64k(t); | 
|  | t = NULL; | 
|  | goto out; | 
|  | } | 
|  | } | 
|  |  | 
|  | t->t[0]->t[128] = *g; | 
|  | for (j = 64; j > 0; j >>= 1) | 
|  | gf128mul_x_lle(&t->t[0]->t[j], &t->t[0]->t[j + j]); | 
|  |  | 
|  | for (i = 0;;) { | 
|  | for (j = 2; j < 256; j += j) | 
|  | for (k = 1; k < j; ++k) | 
|  | be128_xor(&t->t[i]->t[j + k], | 
|  | &t->t[i]->t[j], &t->t[i]->t[k]); | 
|  |  | 
|  | if (++i >= 16) | 
|  | break; | 
|  |  | 
|  | for (j = 128; j > 0; j >>= 1) { | 
|  | t->t[i]->t[j] = t->t[i - 1]->t[j]; | 
|  | gf128mul_x8_lle(&t->t[i]->t[j]); | 
|  | } | 
|  | } | 
|  |  | 
|  | out: | 
|  | return t; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_init_64k_lle); | 
|  |  | 
|  | struct gf128mul_64k *gf128mul_init_64k_bbe(const be128 *g) | 
|  | { | 
|  | struct gf128mul_64k *t; | 
|  | int i, j, k; | 
|  |  | 
|  | t = kzalloc(sizeof(*t), GFP_KERNEL); | 
|  | if (!t) | 
|  | goto out; | 
|  |  | 
|  | for (i = 0; i < 16; i++) { | 
|  | t->t[i] = kzalloc(sizeof(*t->t[i]), GFP_KERNEL); | 
|  | if (!t->t[i]) { | 
|  | gf128mul_free_64k(t); | 
|  | t = NULL; | 
|  | goto out; | 
|  | } | 
|  | } | 
|  |  | 
|  | t->t[0]->t[1] = *g; | 
|  | for (j = 1; j <= 64; j <<= 1) | 
|  | gf128mul_x_bbe(&t->t[0]->t[j + j], &t->t[0]->t[j]); | 
|  |  | 
|  | for (i = 0;;) { | 
|  | for (j = 2; j < 256; j += j) | 
|  | for (k = 1; k < j; ++k) | 
|  | be128_xor(&t->t[i]->t[j + k], | 
|  | &t->t[i]->t[j], &t->t[i]->t[k]); | 
|  |  | 
|  | if (++i >= 16) | 
|  | break; | 
|  |  | 
|  | for (j = 128; j > 0; j >>= 1) { | 
|  | t->t[i]->t[j] = t->t[i - 1]->t[j]; | 
|  | gf128mul_x8_bbe(&t->t[i]->t[j]); | 
|  | } | 
|  | } | 
|  |  | 
|  | out: | 
|  | return t; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_init_64k_bbe); | 
|  |  | 
|  | void gf128mul_free_64k(struct gf128mul_64k *t) | 
|  | { | 
|  | int i; | 
|  |  | 
|  | for (i = 0; i < 16; i++) | 
|  | kfree(t->t[i]); | 
|  | kfree(t); | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_free_64k); | 
|  |  | 
|  | void gf128mul_64k_lle(be128 *a, struct gf128mul_64k *t) | 
|  | { | 
|  | u8 *ap = (u8 *)a; | 
|  | be128 r[1]; | 
|  | int i; | 
|  |  | 
|  | *r = t->t[0]->t[ap[0]]; | 
|  | for (i = 1; i < 16; ++i) | 
|  | be128_xor(r, r, &t->t[i]->t[ap[i]]); | 
|  | *a = *r; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_64k_lle); | 
|  |  | 
|  | void gf128mul_64k_bbe(be128 *a, struct gf128mul_64k *t) | 
|  | { | 
|  | u8 *ap = (u8 *)a; | 
|  | be128 r[1]; | 
|  | int i; | 
|  |  | 
|  | *r = t->t[0]->t[ap[15]]; | 
|  | for (i = 1; i < 16; ++i) | 
|  | be128_xor(r, r, &t->t[i]->t[ap[15 - i]]); | 
|  | *a = *r; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_64k_bbe); | 
|  |  | 
|  | /*      This version uses 4k bytes of table space. | 
|  | A 16 byte buffer has to be multiplied by a 16 byte key | 
|  | value in GF(128).  If we consider a GF(128) value in a | 
|  | single byte, we can construct a table of the 256 16 byte | 
|  | values that result from the 256 values of this byte. | 
|  | This requires 4096 bytes. If we take the highest byte in | 
|  | the buffer and use this table to get the result, we then | 
|  | have to multiply by x^120 to get the final value. For the | 
|  | next highest byte the result has to be multiplied by x^112 | 
|  | and so on. But we can do this by accumulating the result | 
|  | in an accumulator starting with the result for the top | 
|  | byte.  We repeatedly multiply the accumulator value by | 
|  | x^8 and then add in (i.e. xor) the 16 bytes of the next | 
|  | lower byte in the buffer, stopping when we reach the | 
|  | lowest byte. This requires a 4096 byte table. | 
|  | */ | 
|  | struct gf128mul_4k *gf128mul_init_4k_lle(const be128 *g) | 
|  | { | 
|  | struct gf128mul_4k *t; | 
|  | int j, k; | 
|  |  | 
|  | t = kzalloc(sizeof(*t), GFP_KERNEL); | 
|  | if (!t) | 
|  | goto out; | 
|  |  | 
|  | t->t[128] = *g; | 
|  | for (j = 64; j > 0; j >>= 1) | 
|  | gf128mul_x_lle(&t->t[j], &t->t[j+j]); | 
|  |  | 
|  | for (j = 2; j < 256; j += j) | 
|  | for (k = 1; k < j; ++k) | 
|  | be128_xor(&t->t[j + k], &t->t[j], &t->t[k]); | 
|  |  | 
|  | out: | 
|  | return t; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_init_4k_lle); | 
|  |  | 
|  | struct gf128mul_4k *gf128mul_init_4k_bbe(const be128 *g) | 
|  | { | 
|  | struct gf128mul_4k *t; | 
|  | int j, k; | 
|  |  | 
|  | t = kzalloc(sizeof(*t), GFP_KERNEL); | 
|  | if (!t) | 
|  | goto out; | 
|  |  | 
|  | t->t[1] = *g; | 
|  | for (j = 1; j <= 64; j <<= 1) | 
|  | gf128mul_x_bbe(&t->t[j + j], &t->t[j]); | 
|  |  | 
|  | for (j = 2; j < 256; j += j) | 
|  | for (k = 1; k < j; ++k) | 
|  | be128_xor(&t->t[j + k], &t->t[j], &t->t[k]); | 
|  |  | 
|  | out: | 
|  | return t; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_init_4k_bbe); | 
|  |  | 
|  | void gf128mul_4k_lle(be128 *a, struct gf128mul_4k *t) | 
|  | { | 
|  | u8 *ap = (u8 *)a; | 
|  | be128 r[1]; | 
|  | int i = 15; | 
|  |  | 
|  | *r = t->t[ap[15]]; | 
|  | while (i--) { | 
|  | gf128mul_x8_lle(r); | 
|  | be128_xor(r, r, &t->t[ap[i]]); | 
|  | } | 
|  | *a = *r; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_4k_lle); | 
|  |  | 
|  | void gf128mul_4k_bbe(be128 *a, struct gf128mul_4k *t) | 
|  | { | 
|  | u8 *ap = (u8 *)a; | 
|  | be128 r[1]; | 
|  | int i = 0; | 
|  |  | 
|  | *r = t->t[ap[0]]; | 
|  | while (++i < 16) { | 
|  | gf128mul_x8_bbe(r); | 
|  | be128_xor(r, r, &t->t[ap[i]]); | 
|  | } | 
|  | *a = *r; | 
|  | } | 
|  | EXPORT_SYMBOL(gf128mul_4k_bbe); | 
|  |  | 
|  | MODULE_LICENSE("GPL"); | 
|  | MODULE_DESCRIPTION("Functions for multiplying elements of GF(2^128)"); |