diff --git a/include/mbedtls/gf128mul.h b/include/mbedtls/gf128mul.h new file mode 100644 index 000000000..41de39c42 --- /dev/null +++ b/include/mbedtls/gf128mul.h @@ -0,0 +1,46 @@ +/** + * \file gf128mul.h + * + * \brief Fast multiplication in GF(128) + * + * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * This file is part of mbed TLS (https://tls.mbed.org) + */ +#ifndef MBEDTLS_GF128MUL_H +#define MBEDTLS_GF128MUL_H + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * \brief Big-Endian definition for 128 bits elements + */ +typedef unsigned char be128[16]; + +/** + * \brief Multiplication in GF(128): + * r = x times x^4 times x^8 in GF(2^128) + * + * \param x the 128-bits number you want to multiply + * \param r result + */ +void gf128mul_x_ble(be128 r, const be128 x); + + + +#endif /* gf128mul.h */ \ No newline at end of file diff --git a/library/CMakeLists.txt b/library/CMakeLists.txt index 60fa7f8f3..03d3f6c65 100644 --- a/library/CMakeLists.txt +++ b/library/CMakeLists.txt @@ -29,6 +29,7 @@ set(src_crypto entropy_poll.c error.c gcm.c + gf128mul.c havege.c hkdf.c hmac_drbg.c diff --git a/library/gf128mul.c b/library/gf128mul.c new file mode 100644 index 000000000..251398f47 --- /dev/null +++ b/library/gf128mul.c @@ -0,0 +1,78 @@ +/* + * GF(2^128) multiplication functions + * + * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed under the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + * + * This file is part of mbed TLS (https://tls.mbed.org) + */ +#include + +#include "mbedtls/gf128mul.h" + +/* Endianess with 64 bits values */ +#ifndef GET_UINT64_LE +#define GET_UINT64_LE(n,b,i) \ +{ \ + (n) = ( (uint64_t) (b)[(i) + 7] << 56 ) \ + | ( (uint64_t) (b)[(i) + 6] << 48 ) \ + | ( (uint64_t) (b)[(i) + 5] << 40 ) \ + | ( (uint64_t) (b)[(i) + 4] << 32 ) \ + | ( (uint64_t) (b)[(i) + 3] << 24 ) \ + | ( (uint64_t) (b)[(i) + 2] << 16 ) \ + | ( (uint64_t) (b)[(i) + 1] << 8 ) \ + | ( (uint64_t) (b)[(i) ] ); \ +} +#endif + +#ifndef PUT_UINT64_LE +#define PUT_UINT64_LE(n,b,i) \ +{ \ + (b)[(i) + 7] = (unsigned char) ( (n) >> 56 ); \ + (b)[(i) + 6] = (unsigned char) ( (n) >> 48 ); \ + (b)[(i) + 5] = (unsigned char) ( (n) >> 40 ); \ + (b)[(i) + 4] = (unsigned char) ( (n) >> 32 ); \ + (b)[(i) + 3] = (unsigned char) ( (n) >> 24 ); \ + (b)[(i) + 2] = (unsigned char) ( (n) >> 16 ); \ + (b)[(i) + 1] = (unsigned char) ( (n) >> 8 ); \ + (b)[(i) ] = (unsigned char) ( (n) ); \ +} +#endif + + +/* Jump table for not having ifs */ +static const uint16_t gf128mul_table_bbe[2] = { 0x00, 0x87 }; + + +/* + * This function multiply a field element by x, by x^4 and by x^8 + * in the polynomial field representation. It uses 64-bit word operations + * to gain speed but compensates for machine endianess and hence works + * correctly on both styles of machine. + */ +void mbedtls_gf128mul_x_ble(mbedtls_be128 r, const mbedtls_be128 x) +{ + uint64_t a, b, ra, rb; + + GET_UINT64_LE(a, x, 0); + GET_UINT64_LE(b, x, 8); + + ra = (a << 1) ^ gf128mul_table_bbe[b >> 63]; + rb = (a >> 63) | (b << 1); + + PUT_UINT64_LE(ra, r, 0); + PUT_UINT64_LE(rb, r, 8); +} +