2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Christian Grothoff (and other contributing authors)
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6 it under the terms of the GNU General Public License as published
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13 General Public License for more details.
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22 * @file include/gnunet_crypto_lib.h
23 * @brief cryptographic primitives for GNUnet
25 * @author Christian Grothoff
26 * @author Krista Bennett
27 * @author Gerd Knorr <kraxel@bytesex.org>
28 * @author Ioana Patrascu
29 * @author Tzvetan Horozov
32 #ifndef GNUNET_CRYPTO_LIB_H
33 #define GNUNET_CRYPTO_LIB_H
38 #if 0 /* keep Emacsens' auto-indent happy */
43 #include "gnunet_common.h"
44 #include "gnunet_scheduler_lib.h"
47 * Desired quality level for cryptographic operations.
49 enum GNUNET_CRYPTO_Quality
52 * No good quality of the operation is needed (i.e.,
53 * random numbers can be pseudo-random).
55 GNUNET_CRYPTO_QUALITY_WEAK,
58 * High-quality operations are desired.
60 GNUNET_CRYPTO_QUALITY_STRONG,
63 * Randomness for IVs etc. is required.
65 GNUNET_CRYPTO_QUALITY_NONCE
70 * @brief length of the sessionkey in bytes (256 BIT sessionkey)
72 #define GNUNET_CRYPTO_AES_KEY_LENGTH (256/8)
76 * @brief Length of RSA encrypted data (2048 bit)
78 * We currently do not handle encryption of data
79 * that can not be done in a single call to the
80 * RSA methods (read: large chunks of data).
81 * We should never need that, as we can use
82 * the GNUNET_CRYPTO_hash for larger pieces of data for signing,
83 * and for encryption, we only need to encode sessionkeys!
85 #define GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH 256
89 * Length of an RSA KEY (d,e,len), 2048 bit (=256 octests) key d, 2 byte e
91 #define GNUNET_CRYPTO_RSA_KEY_LENGTH 258
95 * Length of a hash value
97 #define GNUNET_CRYPTO_HASH_LENGTH 512/8
100 * The private information of an RSA key pair.
102 struct GNUNET_CRYPTO_RsaPrivateKey;
106 * @brief 0-terminated ASCII encoding of a GNUNET_HashCode.
108 struct GNUNET_CRYPTO_HashAsciiEncoded
110 unsigned char encoding[104];
116 * @brief an RSA signature
118 struct GNUNET_CRYPTO_RsaSignature
120 unsigned char sig[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH];
125 * @brief header of what an RSA signature signs
126 * this must be followed by "size - 8" bytes of
127 * the actual signed data
129 struct GNUNET_CRYPTO_RsaSignaturePurpose
132 * How many bytes does this signature sign?
133 * (including this purpose header); in network
136 uint32_t size GNUNET_PACKED;
139 * What does this signature vouch for? This
140 * must contain a GNUNET_SIGNATURE_PURPOSE_XXX
141 * constant (from gnunet_signatures.h). In
142 * network byte order!
144 uint32_t purpose GNUNET_PACKED;
150 * @brief A public key.
152 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
155 * In big-endian, must be GNUNET_CRYPTO_RSA_KEY_LENGTH+4
157 uint16_t len GNUNET_PACKED;
160 * Size of n in key; in big-endian!
162 uint16_t sizen GNUNET_PACKED;
165 * The key itself, contains n followed by e.
167 unsigned char key[GNUNET_CRYPTO_RSA_KEY_LENGTH];
170 * Padding (must be 0)
172 uint16_t padding GNUNET_PACKED;
177 * RSA Encrypted data.
179 struct GNUNET_CRYPTO_RsaEncryptedData
181 unsigned char encoding[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH];
186 * @brief type for session keys
188 struct GNUNET_CRYPTO_AesSessionKey
193 unsigned char key[GNUNET_CRYPTO_AES_KEY_LENGTH];
198 uint32_t crc32 GNUNET_PACKED;
203 * @brief IV for sym cipher
205 * NOTE: must be smaller (!) in size than the
208 struct GNUNET_CRYPTO_AesInitializationVector
210 unsigned char iv[GNUNET_CRYPTO_AES_KEY_LENGTH / 2];
215 * @brief type for (message) authentication keys
217 struct GNUNET_CRYPTO_AuthKey
219 unsigned char key[GNUNET_CRYPTO_HASH_LENGTH];
223 /* **************** Functions and Macros ************* */
226 * Seed a weak random generator. Only GNUNET_CRYPTO_QUALITY_WEAK-mode generator
229 * @param seed the seed to use
232 GNUNET_CRYPTO_seed_weak_random (int32_t seed);
235 * Compute the CRC32 checksum for the first len
236 * bytes of the buffer.
238 * @param buf the data over which we're taking the CRC
239 * @param len the length of the buffer in bytes
240 * @return the resulting CRC32 checksum
243 GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
247 * Produce a random value.
249 * @param mode desired quality of the random number
250 * @param i the upper limit (exclusive) for the random number
251 * @return a random value in the interval [0,i) (exclusive).
254 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
258 * Random on unsigned 64-bit values.
260 * @param mode desired quality of the random number
261 * @param max value returned will be in range [0,max) (exclusive)
262 * @return random 64-bit number
265 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max);
269 * Get an array with a random permutation of the
271 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
272 * @param n the size of the array
273 * @return the permutation array (allocated from heap)
276 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n);
280 * Create a new Session key.
282 * @param key key to initialize
285 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key);
288 * Check that a new session key is well-formed.
290 * @param key key to check
291 * @return GNUNET_OK if the key is valid
294 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
299 * Encrypt a block with the public key of another
300 * host that uses the same cyper.
302 * @param block the block to encrypt
303 * @param len the size of the block
304 * @param sessionkey the key used to encrypt
305 * @param iv the initialization vector to use, use INITVALUE
307 * @return the size of the encrypted block, -1 for errors
310 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
311 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
312 const struct GNUNET_CRYPTO_AesInitializationVector
317 * Decrypt a given block with the sessionkey.
319 * @param block the data to decrypt, encoded as returned by encrypt
320 * @param size how big is the block?
321 * @param sessionkey the key used to decrypt
322 * @param iv the initialization vector to use
323 * @param result address to store the result at
324 * @return -1 on failure, size of decrypted block on success
327 GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size,
328 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
329 const struct GNUNET_CRYPTO_AesInitializationVector
334 * @brief Derive an IV
335 * @param iv initialization vector
336 * @param skey session key
337 * @param salt salt for the derivation
338 * @param salt_len size of the salt
339 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
342 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
343 const struct GNUNET_CRYPTO_AesSessionKey *skey,
344 const void *salt, size_t salt_len, ...);
348 * @brief Derive an IV
349 * @param iv initialization vector
350 * @param skey session key
351 * @param salt salt for the derivation
352 * @param salt_len size of the salt
353 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
356 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
357 const struct GNUNET_CRYPTO_AesSessionKey *skey,
358 const void *salt, size_t salt_len, va_list argp);
362 * Convert hash to ASCII encoding.
363 * @param block the hash code
364 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
365 * safely cast to char*, a '\\0' termination is set).
368 GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
369 struct GNUNET_CRYPTO_HashAsciiEncoded *result);
373 * Convert ASCII encoding back to GNUNET_CRYPTO_hash
374 * @param enc the encoding
375 * @param result where to store the GNUNET_CRYPTO_hash code
376 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
379 GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result);
383 * Compute the distance between 2 hashcodes.
384 * The computation must be fast, not involve
385 * a.a or a.e (they're used elsewhere), and
386 * be somewhat consistent. And of course, the
387 * result should be a positive number.
389 * @param a some hash code
390 * @param b some hash code
391 * @return number between 0 and UINT32_MAX
394 GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
395 const GNUNET_HashCode * b);
399 * Compute hash of a given block.
401 * @param block the data to hash
402 * @param size size of the block
403 * @param ret pointer to where to write the hashcode
406 GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret);
410 * Calculate HMAC of a message (RFC 2104)
412 * @param key secret key
413 * @param plaintext input plaintext
414 * @param plaintext_len length of plaintext
415 * @param hmac where to store the hmac
418 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
419 const void *plaintext, size_t plaintext_len,
420 GNUNET_HashCode * hmac);
424 * Function called once the hash computation over the
425 * specified file has completed.
428 * @param res resulting hash, NULL on error
430 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
431 const GNUNET_HashCode *
436 * Handle to file hashing operation.
438 struct GNUNET_CRYPTO_FileHashContext;
441 * Compute the hash of an entire file.
443 * @param priority scheduling priority to use
444 * @param filename name of file to hash
445 * @param blocksize number of bytes to process in one task
446 * @param callback function to call upon completion
447 * @param callback_cls closure for callback
448 * @return NULL on (immediate) errror
450 struct GNUNET_CRYPTO_FileHashContext *
451 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
452 const char *filename, size_t blocksize,
453 GNUNET_CRYPTO_HashCompletedCallback callback,
458 * Cancel a file hashing operation.
460 * @param fhc operation to cancel (callback must not yet have been invoked)
463 GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc);
467 * Create a random hash code.
469 * @param mode desired quality level
470 * @param result hash code that is randomized
473 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
474 GNUNET_HashCode * result);
478 * compute result(delta) = b - a
480 * @param a some hash code
481 * @param b some hash code
482 * @param result set to b - a
485 GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
486 const GNUNET_HashCode * b,
487 GNUNET_HashCode * result);
491 * compute result(b) = a + delta
493 * @param a some hash code
494 * @param delta some hash code
495 * @param result set to a + delta
498 GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
499 const GNUNET_HashCode * delta,
500 GNUNET_HashCode * result);
504 * compute result = a ^ b
506 * @param a some hash code
507 * @param b some hash code
508 * @param result set to a ^ b
511 GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
512 GNUNET_HashCode * result);
516 * Convert a hashcode into a key.
518 * @param hc hash code that serves to generate the key
519 * @param skey set to a valid session key
520 * @param iv set to a valid initialization vector
523 GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
524 struct GNUNET_CRYPTO_AesSessionKey *skey,
525 struct GNUNET_CRYPTO_AesInitializationVector
530 * Obtain a bit from a hashcode.
532 * @param code the GNUNET_CRYPTO_hash to index bit-wise
533 * @param bit index into the hashcode, [0...159]
534 * @return Bit \a bit from hashcode \a code, -1 for invalid index
537 GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit);
540 * Determine how many low order bits match in two
541 * GNUNET_HashCodes. i.e. - 010011 and 011111 share
542 * the first two lowest order bits, and therefore the
543 * return value is two (NOT XOR distance, nor how many
544 * bits match absolutely!).
546 * @param first the first hashcode
547 * @param second the hashcode to compare first to
549 * @return the number of bits that match
552 GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
553 const GNUNET_HashCode * second);
557 * Compare function for HashCodes, producing a total ordering
560 * @param h1 some hash code
561 * @param h2 some hash code
562 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
565 GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2);
569 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
570 * in the XOR metric (Kademlia).
572 * @param h1 some hash code
573 * @param h2 some hash code
574 * @param target some hash code
575 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
578 GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
579 const GNUNET_HashCode * h2,
580 const GNUNET_HashCode * target);
584 * @brief Derive an authentication key
585 * @param key authentication key
586 * @param rkey root key
588 * @param salt_len size of the salt
589 * @param argp pair of void * & size_t for context chunks, terminated by NULL
592 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
593 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
594 const void *salt, size_t salt_len,
599 * @brief Derive an authentication key
600 * @param key authentication key
601 * @param rkey root key
603 * @param salt_len size of the salt
604 * @param ... pair of void * & size_t for context chunks, terminated by NULL
607 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
608 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
609 const void *salt, size_t salt_len, ...);
613 * @param result buffer for the derived key, allocated by caller
614 * @param out_len desired length of the derived key
615 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
616 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
618 * @param xts_len length of xts
619 * @param skm source key material
620 * @param skm_len length of skm
621 * @return GNUNET_YES on success
624 GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
625 const void *xts, size_t xts_len, const void *skm,
626 size_t skm_len, ...);
631 * @param result buffer for the derived key, allocated by caller
632 * @param out_len desired length of the derived key
633 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
634 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
636 * @param xts_len length of xts
637 * @param skm source key material
638 * @param skm_len length of skm
639 * @param argp va_list of void * & size_t pairs for context chunks
640 * @return GNUNET_YES on success
643 GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
644 const void *xts, size_t xts_len, const void *skm,
645 size_t skm_len, va_list argp);
650 * @param result buffer for the derived key, allocated by caller
651 * @param out_len desired length of the derived key
653 * @param xts_len length of xts
654 * @param skm source key material
655 * @param skm_len length of skm
656 * @param argp va_list of void * & size_t pairs for context chunks
657 * @return GNUNET_YES on success
660 GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts,
661 size_t xts_len, const void *skm, size_t skm_len,
667 * @param result buffer for the derived key, allocated by caller
668 * @param out_len desired length of the derived key
670 * @param xts_len length of xts
671 * @param skm source key material
672 * @param skm_len length of skm
673 * @param ... void * & size_t pairs for context chunks
674 * @return GNUNET_YES on success
677 GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts,
678 size_t xts_len, const void *skm, size_t skm_len, ...);
682 * Create a new private key. Caller must free return value.
684 * @return fresh private key
686 struct GNUNET_CRYPTO_RsaPrivateKey *
687 GNUNET_CRYPTO_rsa_key_create (void);
690 * Decode the private key from the data-format back
691 * to the "normal", internal format.
693 * @param buf the buffer where the private key data is stored
694 * @param len the length of the data in 'buffer'
696 struct GNUNET_CRYPTO_RsaPrivateKey *
697 GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len);
700 * Create a new private key by reading it from a file. If the
701 * files does not exist, create a new key and write it to the
702 * file. Caller must free return value. Note that this function
703 * can not guarantee that another process might not be trying
704 * the same operation on the same file at the same time.
705 * If the contents of the file
706 * are invalid the old file is deleted and a fresh key is
709 * @param filename name of file to use for storage
710 * @return new private key, NULL on error (for example,
713 struct GNUNET_CRYPTO_RsaPrivateKey *
714 GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
718 * Deterministically (!) create a private key using only the
719 * given HashCode as input to the PRNG.
721 * @param hc "random" input to PRNG
722 * @return some private key purely dependent on input
724 struct GNUNET_CRYPTO_RsaPrivateKey *
725 GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc);
729 * Free memory occupied by the private key.
730 * @param hostkey pointer to the memory to free
733 GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey);
737 * Extract the public key of the host.
739 * @param priv the private key
740 * @param pub where to write the public key
743 GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey
745 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
750 * Encrypt a block with the public key of another host that uses the
753 * @param block the block to encrypt
754 * @param size the size of block
755 * @param publicKey the encoded public key used to encrypt
756 * @param target where to store the encrypted block
757 * @return GNUNET_SYSERR on error, GNUNET_OK if ok
760 GNUNET_CRYPTO_rsa_encrypt (const void *block, size_t size,
761 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
763 struct GNUNET_CRYPTO_RsaEncryptedData *target);
767 * Decrypt a given block with the hostkey.
769 * @param key the key to use
770 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
771 * @param result pointer to a location where the result can be stored
772 * @param max how many bytes of a result are expected? Must be exact.
773 * @return the size of the decrypted block (that is, size) or -1 on error
776 GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
777 const struct GNUNET_CRYPTO_RsaEncryptedData *block,
778 void *result, size_t max);
782 * Sign a given block.
784 * @param key private key to use for the signing
785 * @param purpose what to sign (size, purpose)
786 * @param sig where to write the signature
787 * @return GNUNET_SYSERR on error, GNUNET_OK on success
790 GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
791 const struct GNUNET_CRYPTO_RsaSignaturePurpose *purpose,
792 struct GNUNET_CRYPTO_RsaSignature *sig);
796 * Verify signature. Note that the caller MUST have already
797 * checked that "validate->size" bytes are actually available.
799 * @param purpose what is the purpose that validate should have?
800 * @param validate block to validate (size, purpose, data)
801 * @param sig signature that is being validated
802 * @param publicKey public key of the signer
803 * @return GNUNET_OK if ok, GNUNET_SYSERR if invalid
806 GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
807 const struct GNUNET_CRYPTO_RsaSignaturePurpose
809 const struct GNUNET_CRYPTO_RsaSignature *sig,
810 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
816 * This function should only be called in testcases
817 * where strong entropy gathering is not desired
818 * (for example, for hostkey generation).
821 GNUNET_CRYPTO_random_disable_entropy_gathering (void);
823 #if 0 /* keep Emacsens' auto-indent happy */
831 /* ifndef GNUNET_CRYPTO_LIB_H */
833 /* end of gnunet_crypto_lib.h */