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