include/nettle/poly1305.h

0001 /* poly1305.h
0002
0003    Poly1305 message authentication code.
0004
0005    Copyright (C) 2013 Nikos Mavrogiannopoulos
0006    Copyright (C) 2013, 2014 Niels Möller
0007
0008    This file is part of GNU Nettle.
0009
0010    GNU Nettle is free software: you can redistribute it and/or
0011    modify it under the terms of either:
0012
0013      * the GNU Lesser General Public License as published by the Free
0014        Software Foundation; either version 3 of the License, or (at your
0015        option) any later version.
0016
0017    or
0018
0019      * the GNU General Public License as published by the Free
0020        Software Foundation; either version 2 of the License, or (at your
0021        option) any later version.
0022
0023    or both in parallel, as here.
0024
0025    GNU Nettle is distributed in the hope that it will be useful,
0026    but WITHOUT ANY WARRANTY; without even the implied warranty of
0027    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0028    General Public License for more details.
0029
0030    You should have received copies of the GNU General Public License and
0031    the GNU Lesser General Public License along with this program.  If
0032    not, see http://www.gnu.org/licenses/.
0033 */
0034
0035 #ifndef NETTLE_POLY1305_H_INCLUDED
0036 #define NETTLE_POLY1305_H_INCLUDED
0037
0038 #include "aes.h"
0039
0040 #ifdef __cplusplus
0041 extern "C" {
0042 #endif
0043
0044 /* Name mangling */
0045 #define poly1305_aes_set_key nettle_poly1305_aes_set_key
0046 #define poly1305_aes_set_nonce nettle_poly1305_aes_set_nonce
0047 #define poly1305_aes_update nettle_poly1305_aes_update
0048 #define poly1305_aes_digest nettle_poly1305_aes_digest
0049
0050 /* Low level functions/macros for the poly1305 construction. */
0051
0052 #define POLY1305_BLOCK_SIZE 16
0053
0054 struct poly1305_ctx {
0055   /* Key, 128-bit value and some cached multiples. */
0056   union
0057   {
0058     uint32_t r32[6];
0059     uint64_t r64[3];
0060   } r;
0061   uint32_t s32[3];
0062   /* State, represented as words of 26, 32 or 64 bits, depending on
0063      implementation. */
0064   /* High bits first, to maintain alignment. */
0065   uint32_t hh;
0066   union
0067   {
0068     uint32_t h32[4];
0069     uint64_t h64[2];
0070   } h;
0071 };
0072
0073 /* poly1305-aes */
0074
0075 #define POLY1305_AES_KEY_SIZE 32
0076 #define POLY1305_AES_DIGEST_SIZE 16
0077 #define POLY1305_AES_NONCE_SIZE 16
0078
0079 struct poly1305_aes_ctx
0080 {
0081   /* Keep aes context last, to make it possible to use a general
0082      poly1305_update if other variants are added. */
0083   struct poly1305_ctx pctx;
0084   uint8_t block[POLY1305_BLOCK_SIZE];
0085   unsigned index;
0086   uint8_t nonce[POLY1305_BLOCK_SIZE];
0087   struct aes128_ctx aes;
0088 };
0089
0090 /* Also initialize the nonce to zero. */
0091 void
0092 poly1305_aes_set_key (struct poly1305_aes_ctx *ctx, const uint8_t *key);
0093
0094 /* Optional, if not used, messages get incrementing nonces starting
0095    from zero. */
0096 void
0097 poly1305_aes_set_nonce (struct poly1305_aes_ctx *ctx,
0098                 const uint8_t *nonce);
0099
0100 /* Update is not aes-specific, but since this is the only implemented
0101    variant, we need no more general poly1305_update. */
0102 void
0103 poly1305_aes_update (struct poly1305_aes_ctx *ctx, size_t length, const uint8_t *data);
0104
0105 /* Also increments the nonce */
0106 void
0107 poly1305_aes_digest (struct poly1305_aes_ctx *ctx,
0108                  size_t length, uint8_t *digest);
0109
0110 #ifdef __cplusplus
0111 }
0112 #endif
0113
0114 #endif /* NETTLE_POLY1305_H_INCLUDED */