5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 1997 - 2007 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
23 /****h* silccrypt/SILC Hash Interface
27 * This is the interface for hash functions which are used to create
28 * message digests. The routines are used in various cryptographic
29 * operations. SILC Hash Interface is used for example by the
30 * SILC HMAC Interface (SilcHmac).
34 /****s* silccrypt/SilcHashAPI/SilcHash
38 * typedef struct SilcHashStruct *SilcHash;
42 * This context is the actual hash function context and is allocated
43 * by silc_hash_alloc and given as argument usually to all
44 * silc_hash_* functions. It is freed by the silc_hash_free
48 typedef struct SilcHashStruct *SilcHash;
50 /****s* silccrypt/SilcHashAPI/SilcHashObject
54 * typedef struct { ... } SilcHashObject;
58 * This structure represents one hash function. The hash function's
59 * name, digest length and block length are defined in the structure.
60 * This structure is then given as argument to the silc_hash_register.
61 * That function is used to register all hash functions into SILC.
62 * They can be then allocated by the name found in this structure by
63 * calling the silc_hash_alloc.
73 void (*update)(void *, const unsigned char *, SilcUInt32);
74 void (*final)(void *, unsigned char *);
75 void (*transform)(void *, const unsigned char *);
76 SilcUInt32 (*context_len)();
79 /* Marks for all hash functions. This can be used in silc_hash_unregister
80 to unregister all hash function at once. */
81 #define SILC_ALL_HASH_FUNCTIONS ((SilcHashObject *)1)
83 /* Default hash functions for silc_hash_register_default(). */
84 extern DLLAPI const SilcHashObject silc_default_hash[];
86 /* Default HASH function in the SILC protocol */
87 #define SILC_DEFAULT_HASH "sha1"
88 #define SILC_HASH_MAXLEN 64
92 /* Following macros are used to implement the SILC Hash API. These
93 macros should be used instead of declaring functions by hand. */
95 /* Function names in SILC Hash modules. The name of the hash function
96 is appended into these names and used to the get correct symbol out
97 of the module. All SILC Hash API compliant modules has to support
98 these names as function names (use macros below to assure this). */
99 #define SILC_HASH_SIM_INIT "init"
100 #define SILC_HASH_SIM_UPDATE "update"
101 #define SILC_HASH_SIM_FINAL "final"
102 #define SILC_HASH_SIM_TRANSFORM "transform"
103 #define SILC_HASH_SIM_CONTEXT_LEN "context_len"
105 /* Macros that can be used to declare SILC Hash API functions. */
106 #define SILC_HASH_API_INIT(hash) \
107 void silc_##hash##_init(void *context)
108 #define SILC_HASH_API_UPDATE(hash) \
109 void silc_##hash##_update(void *context, const unsigned char *data, \
111 #define SILC_HASH_API_FINAL(hash) \
112 void silc_##hash##_final(void *context, unsigned char *digest)
113 #define SILC_HASH_API_TRANSFORM(hash) \
114 void silc_##hash##_transform(void *state, const unsigned char *buffer)
115 #define SILC_HASH_API_CONTEXT_LEN(hash) \
116 SilcUInt32 silc_##hash##_context_len()
120 /****f* silccrypt/SilcHashAPI/silc_hash_register
124 * SilcBool silc_hash_register(const SilcHashObject *hash);
128 * Registers a new hash function into the SILC. This function is used
129 * at the initialization of the SILC. All registered hash functions
130 * should be unregistered with silc_hash_unregister. The `hash' includes
131 * the name of the hash function, digest length and block length. Usually
132 * this function is not called directly. Instead, application can call
133 * the silc_hash_register_default to register all default hash functions
134 * that are builtin the sources. Returns FALSE on error.
137 SilcBool silc_hash_register(const SilcHashObject *hash);
139 /****f* silccrypt/SilcHashAPI/silc_hash_unregister
143 * SilcBool silc_hash_unregister(SilcHashObject *hash);
147 * Unregister a hash function from SILC by the SilcHashObject `hash'.
148 * This should be called for all registered hash functions. Returns
152 SilcBool silc_hash_unregister(SilcHashObject *hash);
154 /****f* silccrypt/SilcHashAPI/silc_hash_register_default
158 * SilcBool silc_hash_register_default(void);
162 * Registers all default hash functions into the SILC. These are the
163 * hash functions that are builtin in the sources. See the list of
164 * default hash functions in the silchash.c source file. The application
165 * may use this to register default hash functions if specific hash
166 * function in any specific order is not wanted (application's
167 * configuration usually may decide the order of the registration, in
168 * which case this function should not be used).
171 SilcBool silc_hash_register_default(void);
173 /****f* silccrypt/SilcHashAPI/silc_hash_unregister_all
177 * SilcBool silc_hash_unregister_all(void);
181 * Unregisters all registered hash functions.
184 SilcBool silc_hash_unregister_all(void);
186 /****f* silccrypt/SilcHashAPI/silc_hash_alloc
190 * SilcBool silc_hash_alloc(const char *name, SilcHash *new_hash);
194 * Allocates a new SilcHash object of name of `name'. The new allocated
195 * hash function is returned into `new_hash' pointer. This function
196 * returns FALSE if such hash function does not exist.
199 SilcBool silc_hash_alloc(const char *name, SilcHash *new_hash);
201 /****f* silccrypt/SilcHashAPI/silc_hash_alloc_by_oid
205 * SilcBool silc_hash_alloc_by_oid(const char *oid, SilcHash *new_hash);
209 * Same as silc_hash_alloc but allocates the hash algorithm by the
210 * hash algorithm OID string indicated by `oid'. Returns FALSE if such
211 * hash function does not exist.
214 SilcBool silc_hash_alloc_by_oid(const char *oid, SilcHash *new_hash);
216 /****f* silccrypt/SilcHashAPI/silc_hash_free
220 * void silc_hash_free(SilcHash hash);
224 * Frees the allocated hash function context.
227 void silc_hash_free(SilcHash hash);
229 /****f* silccrypt/SilcHashAPI/silc_hash_is_supported
233 * SilcBool silc_hash_is_supported(const char *name);
237 * Returns TRUE if the hash function indicated by the `name' exists.
240 SilcBool silc_hash_is_supported(const char *name);
242 /****f* silccrypt/SilcHashAPI/silc_hash_get_supported
246 * char *silc_hash_get_supported(void);
250 * Returns comma (`,') separated list of registered hash functions This
251 * is used for example when sending supported hash function list during
252 * the SILC Key Exchange protocol (SKE). The caller must free the returned
256 char *silc_hash_get_supported(void);
258 /****f* silccrypt/SilcHashAPI/silc_hash_len
262 * SilcUInt32 silc_hash_len(SilcHash hash);
266 * Returns the length of the message digest the hash function produce.
269 SilcUInt32 silc_hash_len(SilcHash hash);
271 /****f* silccrypt/SilcHashAPI/silc_hash_block_len
275 * SilcUInt32 silc_hash_block_len(SilcHash hash);
279 * Returns the block length of the hash function.
282 SilcUInt32 silc_hash_block_len(SilcHash hash);
284 /****f* silccrypt/SilcHashAPI/silc_hash_get_name
288 * const char *silc_hash_get_name(SilcHash hash);
292 * Returns the name of the hash function indicated by the `hash' context.
295 const char *silc_hash_get_name(SilcHash hash);
297 /****f* silccrypt/SilcHashAPI/silc_hash_get_oid
301 * const char *silc_hash_get_name(SilcHash hash);
305 * Returns the hash OID string. Returns NULL if the hash doesn't have
306 * OID string. Use strlen() to get the OID string length.
309 const char *silc_hash_get_oid(SilcHash hash);
311 /****f* silccrypt/SilcHashAPI/silc_hash_make
315 * void silc_hash_make(SilcHash hash, const unsigned char *data,
316 * SilcUInt32 len, unsigned char *return_hash);
320 * Computes the message digest (hash) out of the data indicated by
321 * `data' of length of `len' bytes. Returns the message digest to the
322 * `return_hash' buffer which must be at least of the size of the
323 * message digest the `hash' produces.
326 void silc_hash_make(SilcHash hash, const unsigned char *data,
327 SilcUInt32 len, unsigned char *return_hash);
329 /****f* silccrypt/SilcHashAPI/silc_hash_init
333 * void silc_hash_init(SilcHash hash);
337 * Sometimes calling the silc_hash_make might not be the most optimal
338 * case of computing digests. If you have a lot of different data
339 * that you need to put together for computing a digest you may either
340 * put them into a buffer and compute the digest from the buffer by
341 * calling the silc_hash_make, or you can use the silc_hash_init,
342 * silc_hash_update and silc_hash_final to do the digest. This function
343 * prepares the allocated hash function context for this kind of digest
344 * computation. To add the data to be used in the digest computation
345 * call the silc_hash_update function.
348 void silc_hash_init(SilcHash hash);
350 /****f* silccrypt/SilcHashAPI/silc_hash_update
354 * void silc_hash_update(SilcHash hash, const unsigned char *data,
355 * SilcUInt32 data_len);
359 * This function may be called to add data to be used in the digest
360 * computation. This can be called multiple times to add data from
361 * many sources before actually computing the digest. Once you've
362 * added all the data you need you can call the silc_hash_final to
363 * actually produce the message digest value.
367 * unsigned char digest[20];
369 * silc_hash_init(hash);
370 * silc_hash_update(hash, data, data_len);
371 * silc_hash_update(hash, more_data, more_data_len);
372 * silc_hash_final(hash, digest);
375 void silc_hash_update(SilcHash hash, const unsigned char *data,
376 SilcUInt32 data_len);
378 /****f* silccrypt/SilcHashAPI/silc_hash_final
382 * void silc_hash_final(SilcHash hash, unsigned char *return_hash);
386 * This function is used to produce the final message digest from
387 * the data that has been added to the hash function context by calling
388 * the silc_hash_update function. The digest is copied in to the
389 * `return_hash' pointer which must be at least the size that
390 * the silc_hash_len returns.
393 void silc_hash_final(SilcHash hash, unsigned char *return_hash);
395 /****f* silccrypt/SilcHashAPI/silc_hash_transform
399 * void silc_hash_transform(SilcHash hash, void *state,
400 * const unsigned char *data);
404 * This is special function for calling the hash function's internal
405 * digest generation function. The size of the `state' array and the
406 * sizeof the `data' buffer is hash function specific and must be
407 * known by the caller. Usually this function is not needed.
410 void silc_hash_transform(SilcHash hash, void *state,
411 const unsigned char *data);
413 /****f* silccrypt/SilcHashAPI/silc_hash_fingerprint
417 * char *silc_hash_fingerprint(SilcHash hash, const unsigned char *data,
418 * SilcUInt32 data_len);
422 * Utility function which can be used to create a textual fingerprint
423 * out of the data indicated by `data' of length of `data_len' bytes.
424 * If `hash' is NULL then SHA1 hash function is used automatically.
425 * The caller must free the returned string.
427 * Example output could be:
428 * 41BF 5C2E 4149 039A 3917 831F 65C4 0A69 F98B 0A4D
431 char *silc_hash_fingerprint(SilcHash hash, const unsigned char *data,
432 SilcUInt32 data_len);
434 /****f* silccrypt/SilcHashAPI/silc_hash_babbleprint
438 * char *silc_hash_babbleprint(SilcHash hash, const unsigned char *data,
439 * SilcUInt32 data_len);
443 * Utility function which can be used to create a textual babbleprint
444 * out of the data indicated by `data' of length of `data_len' bytes.
445 * If `hash' is NULL then SHA1 hash function is used automatically.
446 * The caller must free the returned string.
448 * The babbleprint is same as fingerprint but encoded in a form which
449 * makes it easier to pronounce. When verifying fingerprint for example
450 * over a phone call, the babbleprint makes it easier to read the
453 * Example output could be:
454 * xiber-zulad-vubug-noban-puvyc-labac-zonos-gedik-novem-rudog-tyxix
457 char *silc_hash_babbleprint(SilcHash hash, const unsigned char *data,
458 SilcUInt32 data_len);