mdw@git.distorted.org.uk Git - catacomb/blob - symm/salsa20.h

   1 /* -*-c-*-
   2  *
   3  * Salsa20 stream cipher
   4  *
   5  * (c) 2015 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 #ifndef CATACOMB_SALSA20_H
  29 #define CATACOMB_SALSA20_H
  30
  31 #ifdef __cplusplus
  32   extern "C" {
  33 #endif
  34
  35 /*----- Header files ------------------------------------------------------*/
  36
  37 #include <mLib/bits.h>
  38
  39 #ifndef CATACOMB_GCIPHER_H
  40 #  include "gcipher.h"
  41 #endif
  42
  43 #ifndef CATACOMB_GRAND_H
  44 #  include "grand.h"
  45 #endif
  46
  47 /*----- Constants ---------------------------------------------------------*/
  48
  49 #define SALSA20_NONCESZ 8u
  50 #define SALSA20_IETF_NONCESZ 12u
  51 #define SALSA20_KEYSZ 32u
  52 #define SALSA20_OUTSZ 64u
  53
  54 #define HSALSA20_INSZ 16u
  55 #define HSALSA20_OUTSZ 32u
  56
  57 #define XSALSA20_NONCESZ 24u
  58 #define XSALSA20_KEYSZ SALSA20_KEYSZ
  59 #define XSALSA20_OUTSZ SALSA20_OUTSZ
  60
  61 /*----- Data structures ---------------------------------------------------*/
  62
  63 typedef uint32 salsa20_matrix[16];
  64
  65 typedef struct salsa20_ctx {
  66   salsa20_matrix a;
  67   octet b[SALSA20_OUTSZ];
  68   unsigned off;
  69 } salsa20_ctx;
  70
  71 #define XSALSA20_DEFCTX(name)                                           \
  72   typedef struct name { salsa20_ctx s; salsa20_matrix k; } name
  73 XSALSA20_DEFCTX(xsalsa20_ctx);
  74 XSALSA20_DEFCTX(xsalsa2012_ctx);
  75 XSALSA20_DEFCTX(xsalsa208_ctx);
  76
  77 /*----- The Salsa20 stream cipher -----------------------------------------*/
  78
  79 /* --- @salsa20_init@ --- *
  80  *
  81  * Arguments:   @salsa20_ctx *ctx@ = context to fill in
  82  *              @const void *key@ = pointer to key material
  83  *              @size_t ksz@ = size of key (either 32 or 16)
  84  *              @const void *nonce@ = initial nonce, or null
  85  *
  86  * Returns:     ---
  87  *
  88  * Use:         Initializes a Salsa20 context ready for use.
  89  */
  90
  91 extern void salsa20_init(salsa20_ctx */*ctx*/,
  92                          const void */*key*/, size_t /*ksz*/,
  93                          const void */*nonce*/);
  94
  95 /* --- @salsa20_setnonce{,_ietf}@ --- *
  96  *
  97  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
  98  *              @const void *nonce@ = the nonce (@SALSA20_NONCESZ@ or
  99  *                      @SALSA20_IETF_NONCESZ@ bytes)
 100  *
 101  * Returns:     ---
 102  *
 103  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 104  *              different message.  The stream position is reset to zero (see
 105  *              @salsa20_seek@ etc.).
 106  */
 107
 108 extern void salsa20_setnonce(salsa20_ctx */*ctx*/, const void */*nonce*/);
 109 extern void salsa20_setnonce_ietf(salsa20_ctx */*ctx*/,
 110                                   const void */*nonce*/);
 111
 112 /* --- @salsa20_seek{,u64,_ietf}@ --- *
 113  *
 114  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 115  *              @unsigned long i@, @kludge64 i@ = new position to set
 116  *
 117  * Returns:     ---
 118  *
 119  * Use:         Sets a new stream position, in units of Salsa20 output
 120  *              blocks, which are @SALSA20_OUTSZ@ bytes each.  Byte
 121  *              granularity can be achieved by calling @salsa20_encrypt@
 122  *              appropriately.
 123  */
 124
 125 extern void salsa20_seek(salsa20_ctx */*ctx*/, unsigned long /*i*/);
 126 extern void salsa20_seeku64(salsa20_ctx */*ctx*/, kludge64 /*i*/);
 127 extern void salsa20_seek_ietf(salsa20_ctx */*ctx*/, uint32 /*i*/);
 128
 129 /* --- @salsa20_tell{,u64,_ietf}@ --- *
 130  *
 131  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 132  *
 133  * Returns:     The current position in the output stream, in blocks,
 134  *              rounding upwards.
 135  */
 136
 137 extern unsigned long salsa20_tell(salsa20_ctx */*ctx*/);
 138 extern kludge64 salsa20_tellu64(salsa20_ctx */*ctx*/);
 139 extern uint32 salsa20_tell_ietf(salsa20_ctx */*ctx*/);
 140
 141 /* --- @salsa20{,12,8}_encrypt@ --- *
 142  *
 143  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 144  *              @const void *src@ = source buffer (or null)
 145  *              @void *dest@ = destination buffer (or null)
 146  *              @size_t sz@ = size of the buffers
 147  *
 148  * Returns:     ---
 149  *
 150  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 151  *              Salsa20 works by XORing plaintext with a keystream, so
 152  *              encryption and decryption are the same operation.  If @dest@
 153  *              is null then ignore @src@ and skip @sz@ bytes of the
 154  *              keystream.  If @src@ is null, then just write the keystream
 155  *              to @dest@.
 156  */
 157
 158 extern void salsa20_encrypt(salsa20_ctx */*ctx*/,
 159                             const void */*src*/, void */*dest*/,
 160                             size_t /*sz*/);
 161 extern void salsa2012_encrypt(salsa20_ctx */*ctx*/,
 162                               const void */*src*/, void */*dest*/,
 163                               size_t /*sz*/);
 164 extern void salsa208_encrypt(salsa20_ctx */*ctx*/,
 165                               const void */*src*/, void */*dest*/,
 166                               size_t /*sz*/);
 167
 168 /*----- The HSalsa20 pseudorandom function --------------------------------*/
 169
 170 /* --- @hsalsa20{,12,8}_prf@ --- *
 171  *
 172  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 173  *              @const void *src@ = the input (@HSALSA20_INSZ@ bytes)
 174  *              @void *dest@ = the output (@HSALSA20_OUTSZ@ bytes)
 175  *
 176  * Returns:     ---
 177  *
 178  * Use:         Apply the HSalsa20/r pseudorandom function to @src@, writing
 179  *              the result to @out@.
 180  */
 181
 182 extern void hsalsa20_prf(salsa20_ctx */*ctx*/,
 183                          const void */*src*/, void */*dest*/);
 184 extern void hsalsa2012_prf(salsa20_ctx */*ctx*/,
 185                            const void */*src*/, void */*dest*/);
 186 extern void hsalsa208_prf(salsa20_ctx */*ctx*/,
 187                           const void */*src*/, void */*dest*/);
 188
 189 /*----- The XSalsa20 stream cipher ----------------------------------------*/
 190
 191 /* --- @xsalsa20{,12,8}_init@ --- *
 192  *
 193  * Arguments:   @xsalsa20R_ctx *ctx@ = the context to fill in
 194  *              @const void *key@ = pointer to key material
 195  *              @size_t ksz@ = size of key (either 32 or 16)
 196  *              @const void *nonce@ = initial nonce, or null
 197  *
 198  * Returns:     ---
 199  *
 200  * Use:         Initializes an XSalsa20/r context ready for use.
 201  *
 202  *              There is a different function for each number of rounds,
 203  *              unlike for plain Salsa20.
 204  */
 205
 206 extern void xsalsa20_init(xsalsa20_ctx */*ctx*/,
 207                           const void */*key*/, size_t /*ksz*/,
 208                           const void */*nonce*/);
 209 extern void xsalsa2012_init(xsalsa2012_ctx */*ctx*/,
 210                             const void */*key*/, size_t /*ksz*/,
 211                             const void */*nonce*/);
 212 extern void xsalsa208_init(xsalsa208_ctx */*ctx*/,
 213                            const void */*key*/, size_t /*ksz*/,
 214                            const void */*nonce*/);
 215
 216 /* --- @xsalsa20{,12,8}_setnonce@ --- *
 217  *
 218  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 219  *              @const void *nonce@ = the nonce (@XSALSA20_NONCESZ@ bytes)
 220  *
 221  * Returns:     ---
 222  *
 223  * Use:         Set a new nonce in the context @ctx@, e.g., for processing a
 224  *              different message.  The stream position is reset to zero (see
 225  *              @salsa20_seek@ etc.).
 226  *
 227  *              There is a different function for each number of rounds,
 228  *              unlike for plain Salsa20.
 229  */
 230
 231 extern void xsalsa20_setnonce(xsalsa20_ctx */*ctx*/,
 232                               const void */*nonce*/);
 233 extern void xsalsa2012_setnonce(xsalsa2012_ctx */*ctx*/,
 234                                 const void */*nonce*/);
 235 extern void xsalsa208_setnonce(xsalsa208_ctx */*ctx*/,
 236                                const void */*nonce*/);
 237
 238 /* --- @xsalsa20{,12,8}_seek@, @xsalsa20{,12,8}_seeku64@ --- *
 239  *
 240  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 241  *              @unsigned long i@, @kludge64 i@ = new position to set
 242  *
 243  * Returns:     ---
 244  *
 245  * Use:         Sets a new stream position, in units of Salsa20 output
 246  *              blocks, which are @XSALSA20_OUTSZ@ bytes each.  Byte
 247  *              granularity can be achieved by calling @xsalsa20R_encrypt@
 248  *              appropriately.
 249  *
 250  *              There is a different function for each number of rounds,
 251  *              unlike for plain Salsa20, because the context structures are
 252  *              different.
 253  */
 254
 255 extern void xsalsa20_seek(xsalsa20_ctx */*ctx*/, unsigned long /*i*/);
 256 extern void xsalsa2012_seek(xsalsa2012_ctx */*ctx*/, unsigned long /*i*/);
 257 extern void xsalsa208_seek(xsalsa208_ctx */*ctx*/, unsigned long /*i*/);
 258 extern void xsalsa20_seeku64(xsalsa20_ctx */*ctx*/, kludge64 /*i*/);
 259 extern void xsalsa2012_seeku64(xsalsa2012_ctx */*ctx*/, kludge64 /*i*/);
 260 extern void xsalsa208_seeku64(xsalsa208_ctx */*ctx*/, kludge64 /*i*/);
 261
 262 /* --- @xsalsa20{,12,8}_tell@, @xsalsa20{,12,8}_tellu64@ --- *
 263  *
 264  * Arguments:   @salsa20_ctx *ctx@ = pointer to context
 265  *
 266  * Returns:     The current position in the output stream, in blocks,
 267  *              rounding upwards.
 268  *
 269  *              There is a different function for each number of rounds,
 270  *              unlike for plain Salsa20, because the context structures are
 271  *              different.
 272  */
 273
 274 extern unsigned long xsalsa20_tell(xsalsa20_ctx */*ctx*/);
 275 extern unsigned long xsalsa2012_tell(xsalsa2012_ctx */*ctx*/);
 276 extern unsigned long xsalsa208_tell(xsalsa208_ctx */*ctx*/);
 277 extern kludge64 xsalsa20_tellu64(xsalsa20_ctx */*ctx*/);
 278 extern kludge64 xsalsa2012_tellu64(xsalsa2012_ctx */*ctx*/);
 279 extern kludge64 xsalsa208_tellu64(xsalsa208_ctx */*ctx*/);
 280
 281 /* --- @xsalsa20{,12,8}_encrypt@ --- *
 282  *
 283  * Arguments:   @xsalsa20R_ctx *ctx@ = pointer to context
 284  *              @const void *src@ = source buffer (or null)
 285  *              @void *dest@ = destination buffer (or null)
 286  *              @size_t sz@ = size of the buffers
 287  *
 288  * Returns:     ---
 289  *
 290  * Use:         Encrypts or decrypts @sz@ bytes of data from @src@ to @dest@.
 291  *              XSalsa20 works by XORing plaintext with a keystream, so
 292  *              encryption and decryption are the same operation.  If @dest@
 293  *              is null then ignore @src@ and skip @sz@ bytes of the
 294  *              keystream.  If @src@ is null, then just write the keystream
 295  *              to @dest@.
 296  */
 297
 298 extern void xsalsa20_encrypt(xsalsa20_ctx */*ctx*/,
 299                             const void */*src*/, void */*dest*/,
 300                             size_t /*sz*/);
 301 extern void xsalsa2012_encrypt(xsalsa2012_ctx */*ctx*/,
 302                               const void */*src*/, void */*dest*/,
 303                               size_t /*sz*/);
 304 extern void xsalsa208_encrypt(xsalsa208_ctx */*ctx*/,
 305                               const void */*src*/, void */*dest*/,
 306                               size_t /*sz*/);
 307
 308 /*----- Generic cipher interface ------------------------------------------*/
 309
 310 extern const octet salsa20_keysz[];
 311 #define salsa2012_keysz salsa20_keysz
 312 #define salsa208_keysz salsa20_keysz
 313 #define salsa20_ietf_keysz salsa20_keysz
 314 #define salsa2012_ietf_keysz salsa20_keysz
 315 #define salsa208_ietf_keysz salsa20_keysz
 316 #define xsalsa20_keysz salsa20_keysz
 317 #define xsalsa2012_keysz salsa20_keysz
 318 #define xsalsa208_keysz salsa20_keysz
 319
 320 extern const gccipher salsa20, salsa2012, salsa208;
 321 extern const gccipher salsa20_ietf, salsa2012_ietf, salsa208_ietf;
 322 extern const gccipher xsalsa20, xsalsa2012, xsalsa208;
 323
 324 /*----- Generic random number generator interface -------------------------*/
 325
 326 /* --- @salsa20{,12,8}{,_ietf}_rand@, @xsalsa20{,12,8}{,_ietf}_rand@ --- *
 327  *
 328  * Arguments:           @const void *k@ = pointer to key material
 329  *                      @size_t ksz@ = size of key material
 330  *                      @const void *n@ = pointer to nonce or null
 331  *                              (@SALSA20_NONCESZ@, @SALSA20_IETF_NONCESZ@,
 332  *                              or @XSALSA20_NONCESZ@)
 333  *
 334  * Returns:             Pointer to generic random number generator instance.
 335  *
 336  * Use:                 Creates a random number interface wrapper around
 337  *                      the Salsa20/r or XSalsa20/r stream ciphers.
 338  */
 339
 340 extern grand *salsa20_rand(const void */*k*/, size_t /*ksz*/,
 341                            const void */*n*/);
 342 extern grand *salsa2012_rand(const void */*k*/, size_t /*ksz*/,
 343                              const void */*n*/);
 344 extern grand *salsa208_rand(const void */*k*/, size_t /*ksz*/,
 345                             const void */*n*/);
 346 extern grand *salsa20_ietf_rand(const void */*k*/, size_t /*ksz*/,
 347                                 const void */*n*/);
 348 extern grand *salsa2012_ietf_rand(const void */*k*/, size_t /*ksz*/,
 349                                   const void */*n*/);
 350 extern grand *salsa208_ietf_rand(const void */*k*/, size_t /*ksz*/,
 351                                  const void */*n*/);
 352 extern grand *xsalsa20_rand(const void */*k*/, size_t /*ksz*/,
 353                             const void */*n*/);
 354 extern grand *xsalsa2012_rand(const void */*k*/, size_t /*ksz*/,
 355                               const void */*n*/);
 356 extern grand *xsalsa208_rand(const void */*k*/, size_t /*ksz*/,
 357                              const void */*n*/);
 358
 359 enum {
 360   SALSA20_SEEK = GRAND_SPECIFIC('S'),   /* @unsigned long pos@ */
 361   SALSA20_SEEKU64,                      /* @kludge64 pos@ */
 362   SALSA20_TELL,                         /* @unsigned long *pos@ */
 363   SALSA20_TELLU64                       /* @kludge64 *pos@ */
 364 };
 365
 366 /*----- That's all, folks -------------------------------------------------*/
 367
 368 #ifdef __cplusplus
 369   }
 370 #endif
 371
 372 #endif