2 This file is part of GNUnet.
3 (C) 2001-2013 Christian Grothoff (and other contributing authors)
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13 General Public License for more details.
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23 * @file util/crypto_hash.c
24 * @brief SHA-512 GNUNET_CRYPTO_hash related functions
25 * @author Christian Grothoff
29 #include "gnunet_common.h"
30 #include "gnunet_crypto_lib.h"
31 #include "gnunet_disk_lib.h"
32 #include "gnunet_strings_lib.h"
35 #define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
37 #define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util", syscall, filename)
40 * Hash block of given size.
42 * @param block the data to GNUNET_CRYPTO_hash, length is given as a second argument
43 * @param size the length of the data to GNUNET_CRYPTO_hash
44 * @param ret pointer to where to write the hashcode
47 GNUNET_CRYPTO_hash (const void *block, size_t size, struct GNUNET_HashCode * ret)
49 gcry_md_hash_buffer (GCRY_MD_SHA512, ret, block, size);
54 * Context used when hashing a file.
56 struct GNUNET_CRYPTO_FileHashContext
60 * Function to call upon completion.
62 GNUNET_CRYPTO_HashCompletedCallback callback;
65 * Closure for callback.
72 unsigned char *buffer;
75 * Name of the file we are hashing.
82 struct GNUNET_DISK_FileHandle *fh;
100 * Current task for hashing.
102 GNUNET_SCHEDULER_TaskIdentifier task;
107 enum GNUNET_SCHEDULER_Priority priority;
118 * Report result of hash computation to callback
119 * and free associated resources.
122 file_hash_finish (struct GNUNET_CRYPTO_FileHashContext *fhc,
123 const struct GNUNET_HashCode * res)
125 fhc->callback (fhc->callback_cls, res);
126 GNUNET_free (fhc->filename);
127 if (!GNUNET_DISK_handle_invalid (fhc->fh))
128 GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
129 gcry_md_close (fhc->md);
130 GNUNET_free (fhc); /* also frees fhc->buffer */
141 file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
143 struct GNUNET_CRYPTO_FileHashContext *fhc = cls;
144 struct GNUNET_HashCode *res;
147 fhc->task = GNUNET_SCHEDULER_NO_TASK;
148 GNUNET_assert (fhc->offset <= fhc->fsize);
150 if (fhc->fsize - fhc->offset < delta)
151 delta = fhc->fsize - fhc->offset;
152 if (delta != GNUNET_DISK_file_read (fhc->fh, fhc->buffer, delta))
154 LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "read", fhc->filename);
155 file_hash_finish (fhc, NULL);
158 gcry_md_write (fhc->md, fhc->buffer, delta);
159 fhc->offset += delta;
160 if (fhc->offset == fhc->fsize)
162 res = (struct GNUNET_HashCode *) gcry_md_read (fhc->md, GCRY_MD_SHA512);
163 file_hash_finish (fhc, res);
166 fhc->task = GNUNET_SCHEDULER_add_with_priority (fhc->priority,
167 &file_hash_task, fhc);
172 * Compute the hash of an entire file.
174 * @param priority scheduling priority to use
175 * @param filename name of file to hash
176 * @param blocksize number of bytes to process in one task
177 * @param callback function to call upon completion
178 * @param callback_cls closure for callback
179 * @return NULL on (immediate) errror
181 struct GNUNET_CRYPTO_FileHashContext *
182 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
183 const char *filename, size_t blocksize,
184 GNUNET_CRYPTO_HashCompletedCallback callback,
187 struct GNUNET_CRYPTO_FileHashContext *fhc;
189 GNUNET_assert (blocksize > 0);
191 GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_FileHashContext) + blocksize);
192 fhc->callback = callback;
193 fhc->callback_cls = callback_cls;
194 fhc->buffer = (unsigned char *) &fhc[1];
195 fhc->filename = GNUNET_strdup (filename);
196 if (GPG_ERR_NO_ERROR != gcry_md_open (&fhc->md, GCRY_MD_SHA512, 0))
202 fhc->bsize = blocksize;
203 if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fhc->fsize, GNUNET_NO, GNUNET_YES))
205 GNUNET_free (fhc->filename);
210 GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
211 GNUNET_DISK_PERM_NONE);
214 GNUNET_free (fhc->filename);
218 fhc->priority = priority;
220 GNUNET_SCHEDULER_add_with_priority (priority, &file_hash_task, fhc);
226 * Cancel a file hashing operation.
228 * @param fhc operation to cancel (callback must not yet have been invoked)
231 GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc)
233 GNUNET_SCHEDULER_cancel (fhc->task);
234 GNUNET_free (fhc->filename);
235 GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
240 /* ***************** binary-ASCII encoding *************** */
244 * Convert GNUNET_CRYPTO_hash to ASCII encoding. The ASCII encoding is rather
245 * GNUnet specific. It was chosen such that it only uses characters
246 * in [0-9A-V], can be produced without complex arithmetics and uses a
247 * small number of characters. The GNUnet encoding uses 103
248 * characters plus a null terminator.
250 * @param block the hash code
251 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
252 * safely cast to char*, a '\\0' termination is set).
255 GNUNET_CRYPTO_hash_to_enc (const struct GNUNET_HashCode * block,
256 struct GNUNET_CRYPTO_HashAsciiEncoded *result)
260 np = GNUNET_STRINGS_data_to_string ((const unsigned char *) block,
261 sizeof (struct GNUNET_HashCode),
263 sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
264 GNUNET_assert (NULL != np);
270 * Convert ASCII encoding back to hash code.
272 * @param enc the encoding
273 * @param enclen number of characters in 'enc' (without 0-terminator, which can be missing)
274 * @param result where to store the hash code
275 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
278 GNUNET_CRYPTO_hash_from_string2 (const char *enc, size_t enclen,
279 struct GNUNET_HashCode * result)
281 char upper_enc[enclen];
282 char* up_ptr = upper_enc;
284 GNUNET_STRINGS_utf8_toupper(enc, &up_ptr);
286 return GNUNET_STRINGS_string_to_data (upper_enc, enclen,
287 (unsigned char*) result,
288 sizeof (struct GNUNET_HashCode));
293 * Compute the distance between 2 hashcodes. The computation must be
294 * fast, not involve bits[0] or bits[4] (they're used elsewhere), and be
295 * somewhat consistent. And of course, the result should be a positive
298 * @param a some hash code
299 * @param b some hash code
300 * @return a positive number which is a measure for
301 * hashcode proximity.
304 GNUNET_CRYPTO_hash_distance_u32 (const struct GNUNET_HashCode * a,
305 const struct GNUNET_HashCode * b)
307 unsigned int x1 = (a->bits[1] - b->bits[1]) >> 16;
308 unsigned int x2 = (b->bits[1] - a->bits[1]) >> 16;
315 * Create a random hash code.
317 * @param mode desired quality level
318 * @param result hash code that is randomized
321 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
322 struct GNUNET_HashCode *result)
326 for (i = (sizeof (struct GNUNET_HashCode) / sizeof (uint32_t)) - 1; i >= 0; i--)
327 result->bits[i] = GNUNET_CRYPTO_random_u32 (mode, UINT32_MAX);
332 * compute result(delta) = b - a
334 * @param a some hash code
335 * @param b some hash code
336 * @param result set to b - a
339 GNUNET_CRYPTO_hash_difference (const struct GNUNET_HashCode * a,
340 const struct GNUNET_HashCode * b,
341 struct GNUNET_HashCode * result)
345 for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
346 result->bits[i] = b->bits[i] - a->bits[i];
351 * compute result(b) = a + delta
353 * @param a some hash code
354 * @param delta some hash code
355 * @param result set to a + delta
358 GNUNET_CRYPTO_hash_sum (const struct GNUNET_HashCode * a,
359 const struct GNUNET_HashCode * delta, struct GNUNET_HashCode * result)
363 for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
364 result->bits[i] = delta->bits[i] + a->bits[i];
369 * compute result = a ^ b
371 * @param a some hash code
372 * @param b some hash code
373 * @param result set to a ^ b
376 GNUNET_CRYPTO_hash_xor (const struct GNUNET_HashCode * a, const struct GNUNET_HashCode * b,
377 struct GNUNET_HashCode * result)
381 for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
382 result->bits[i] = a->bits[i] ^ b->bits[i];
387 * Convert a hashcode into a key.
389 * @param hc hash code that serves to generate the key
390 * @param skey set to a valid session key
391 * @param iv set to a valid initialization vector
394 GNUNET_CRYPTO_hash_to_aes_key (const struct GNUNET_HashCode * hc,
395 struct GNUNET_CRYPTO_AesSessionKey *skey,
396 struct GNUNET_CRYPTO_AesInitializationVector *iv)
398 GNUNET_assert (sizeof (struct GNUNET_HashCode) >=
399 GNUNET_CRYPTO_AES_KEY_LENGTH +
400 sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
401 memcpy (skey, hc, GNUNET_CRYPTO_AES_KEY_LENGTH);
402 memcpy (iv, &((char *) hc)[GNUNET_CRYPTO_AES_KEY_LENGTH],
403 sizeof (struct GNUNET_CRYPTO_AesInitializationVector));
408 * Obtain a bit from a hashcode.
409 * @param code the GNUNET_CRYPTO_hash to index bit-wise
410 * @param bit index into the hashcode, [0...511]
411 * @return Bit \a bit from hashcode \a code, -1 for invalid index
414 GNUNET_CRYPTO_hash_get_bit (const struct GNUNET_HashCode * code, unsigned int bit)
416 GNUNET_assert (bit < 8 * sizeof (struct GNUNET_HashCode));
417 return (((unsigned char *) code)[bit >> 3] & (1 << (bit & 7))) > 0;
422 * Determine how many low order bits match in two
423 * struct GNUNET_HashCodes. i.e. - 010011 and 011111 share
424 * the first two lowest order bits, and therefore the
425 * return value is two (NOT XOR distance, nor how many
426 * bits match absolutely!).
428 * @param first the first hashcode
429 * @param second the hashcode to compare first to
431 * @return the number of bits that match
434 GNUNET_CRYPTO_hash_matching_bits (const struct GNUNET_HashCode * first,
435 const struct GNUNET_HashCode * second)
439 for (i = 0; i < sizeof (struct GNUNET_HashCode) * 8; i++)
440 if (GNUNET_CRYPTO_hash_get_bit (first, i) !=
441 GNUNET_CRYPTO_hash_get_bit (second, i))
443 return sizeof (struct GNUNET_HashCode) * 8;
448 * Compare function for HashCodes, producing a total ordering
451 * @param h1 some hash code
452 * @param h2 some hash code
453 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
456 GNUNET_CRYPTO_hash_cmp (const struct GNUNET_HashCode * h1, const struct GNUNET_HashCode * h2)
462 i1 = (unsigned int *) h1;
463 i2 = (unsigned int *) h2;
464 for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
476 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
477 * in the XOR metric (Kademlia).
479 * @param h1 some hash code
480 * @param h2 some hash code
481 * @param target some hash code
482 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
485 GNUNET_CRYPTO_hash_xorcmp (const struct GNUNET_HashCode * h1,
486 const struct GNUNET_HashCode * h2,
487 const struct GNUNET_HashCode * target)
493 for (i = sizeof (struct GNUNET_HashCode) / sizeof (unsigned int) - 1; i >= 0; i--)
495 d1 = ((unsigned int *) h1)[i] ^ ((unsigned int *) target)[i];
496 d2 = ((unsigned int *) h2)[i] ^ ((unsigned int *) target)[i];
507 * @brief Derive an authentication key
508 * @param key authentication key
509 * @param rkey root key
511 * @param salt_len size of the salt
512 * @param ... pair of void * & size_t for context chunks, terminated by NULL
515 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
516 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
517 const void *salt, size_t salt_len, ...)
521 va_start (argp, salt_len);
522 GNUNET_CRYPTO_hmac_derive_key_v (key, rkey, salt, salt_len, argp);
528 * @brief Derive an authentication key
529 * @param key authentication key
530 * @param rkey root key
532 * @param salt_len size of the salt
533 * @param argp pair of void * & size_t for context chunks, terminated by NULL
536 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
537 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
538 const void *salt, size_t salt_len,
541 GNUNET_CRYPTO_kdf_v (key->key, sizeof (key->key), salt, salt_len, rkey->key,
542 sizeof (rkey->key), argp);
547 * Calculate HMAC of a message (RFC 2104)
549 * @param key secret key
550 * @param plaintext input plaintext
551 * @param plaintext_len length of plaintext
552 * @param hmac where to store the hmac
555 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
556 const void *plaintext, size_t plaintext_len,
557 struct GNUNET_HashCode * hmac)
560 const unsigned char *mc;
562 GNUNET_assert (GPG_ERR_NO_ERROR ==
563 gcry_md_open (&md, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC));
564 gcry_md_setkey (md, key->key, sizeof (key->key));
565 gcry_md_write (md, plaintext, plaintext_len);
566 mc = gcry_md_read (md, GCRY_MD_SHA512);
568 memcpy (hmac->bits, mc, sizeof (hmac->bits));
573 /* end of crypto_hash.c */