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];
124 GNUNET_NETWORK_STRUCT_BEGIN
127 * @brief header of what an RSA signature signs
128 * this must be followed by "size - 8" bytes of
129 * the actual signed data
131 struct GNUNET_CRYPTO_RsaSignaturePurpose
134 * How many bytes does this signature sign?
135 * (including this purpose header); in network
138 uint32_t size GNUNET_PACKED;
141 * What does this signature vouch for? This
142 * must contain a GNUNET_SIGNATURE_PURPOSE_XXX
143 * constant (from gnunet_signatures.h). In
144 * network byte order!
146 uint32_t purpose GNUNET_PACKED;
152 * @brief A public key.
154 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
157 * In big-endian, must be GNUNET_CRYPTO_RSA_KEY_LENGTH+4
159 uint16_t len GNUNET_PACKED;
162 * Size of n in key; in big-endian!
164 uint16_t sizen GNUNET_PACKED;
167 * The key itself, contains n followed by e.
169 unsigned char key[GNUNET_CRYPTO_RSA_KEY_LENGTH];
172 * Padding (must be 0)
174 uint16_t padding GNUNET_PACKED;
179 * RSA Encrypted data.
181 struct GNUNET_CRYPTO_RsaEncryptedData
183 unsigned char encoding[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH];
188 * @brief type for session keys
190 struct GNUNET_CRYPTO_AesSessionKey
195 unsigned char key[GNUNET_CRYPTO_AES_KEY_LENGTH];
200 uint32_t crc32 GNUNET_PACKED;
202 GNUNET_NETWORK_STRUCT_END
205 * @brief IV for sym cipher
207 * NOTE: must be smaller (!) in size than the
210 struct GNUNET_CRYPTO_AesInitializationVector
212 unsigned char iv[GNUNET_CRYPTO_AES_KEY_LENGTH / 2];
217 * @brief type for (message) authentication keys
219 struct GNUNET_CRYPTO_AuthKey
221 unsigned char key[GNUNET_CRYPTO_HASH_LENGTH];
225 /* **************** Functions and Macros ************* */
228 * Seed a weak random generator. Only GNUNET_CRYPTO_QUALITY_WEAK-mode generator
231 * @param seed the seed to use
234 GNUNET_CRYPTO_seed_weak_random (int32_t seed);
237 * Compute the CRC32 checksum for the first len
238 * bytes of the buffer.
240 * @param buf the data over which we're taking the CRC
241 * @param len the length of the buffer in bytes
242 * @return the resulting CRC32 checksum
245 GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
249 * Produce a random value.
251 * @param mode desired quality of the random number
252 * @param i the upper limit (exclusive) for the random number
253 * @return a random value in the interval [0,i) (exclusive).
256 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
260 * Random on unsigned 64-bit values.
262 * @param mode desired quality of the random number
263 * @param max value returned will be in range [0,max) (exclusive)
264 * @return random 64-bit number
267 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max);
271 * Get an array with a random permutation of the
273 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
274 * @param n the size of the array
275 * @return the permutation array (allocated from heap)
278 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n);
282 * Create a new Session key.
284 * @param key key to initialize
287 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key);
290 * Check that a new session key is well-formed.
292 * @param key key to check
293 * @return GNUNET_OK if the key is valid
296 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
301 * Encrypt a block with the public key of another
302 * host that uses the same cyper.
304 * @param block the block to encrypt
305 * @param len the size of the block
306 * @param sessionkey the key used to encrypt
307 * @param iv the initialization vector to use, use INITVALUE
309 * @return the size of the encrypted block, -1 for errors
312 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
313 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
314 const struct GNUNET_CRYPTO_AesInitializationVector
319 * Decrypt a given block with the sessionkey.
321 * @param block the data to decrypt, encoded as returned by encrypt
322 * @param size how big is the block?
323 * @param sessionkey the key used to decrypt
324 * @param iv the initialization vector to use
325 * @param result address to store the result at
326 * @return -1 on failure, size of decrypted block on success
329 GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size,
330 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
331 const struct GNUNET_CRYPTO_AesInitializationVector
336 * @brief Derive an IV
337 * @param iv initialization vector
338 * @param skey session key
339 * @param salt salt for the derivation
340 * @param salt_len size of the salt
341 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
344 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
345 const struct GNUNET_CRYPTO_AesSessionKey *skey,
346 const void *salt, size_t salt_len, ...);
350 * @brief Derive an IV
351 * @param iv initialization vector
352 * @param skey session key
353 * @param salt salt for the derivation
354 * @param salt_len size of the salt
355 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
358 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
359 const struct GNUNET_CRYPTO_AesSessionKey *skey,
360 const void *salt, size_t salt_len, va_list argp);
364 * Convert hash to ASCII encoding.
365 * @param block the hash code
366 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
367 * safely cast to char*, a '\\0' termination is set).
370 GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
371 struct GNUNET_CRYPTO_HashAsciiEncoded *result);
375 * Convert ASCII encoding back to GNUNET_CRYPTO_hash
376 * @param enc the encoding
377 * @param result where to store the GNUNET_CRYPTO_hash code
378 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
381 GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result);
385 * Compute the distance between 2 hashcodes.
386 * The computation must be fast, not involve
387 * a.a or a.e (they're used elsewhere), and
388 * be somewhat consistent. And of course, the
389 * result should be a positive number.
391 * @param a some hash code
392 * @param b some hash code
393 * @return number between 0 and UINT32_MAX
396 GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
397 const GNUNET_HashCode * b);
401 * Compute hash of a given block.
403 * @param block the data to hash
404 * @param size size of the block
405 * @param ret pointer to where to write the hashcode
408 GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret);
412 * Calculate HMAC of a message (RFC 2104)
414 * @param key secret key
415 * @param plaintext input plaintext
416 * @param plaintext_len length of plaintext
417 * @param hmac where to store the hmac
420 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
421 const void *plaintext, size_t plaintext_len,
422 GNUNET_HashCode * hmac);
426 * Function called once the hash computation over the
427 * specified file has completed.
430 * @param res resulting hash, NULL on error
432 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
433 const GNUNET_HashCode *
438 * Handle to file hashing operation.
440 struct GNUNET_CRYPTO_FileHashContext;
443 * Compute the hash of an entire file.
445 * @param priority scheduling priority to use
446 * @param filename name of file to hash
447 * @param blocksize number of bytes to process in one task
448 * @param callback function to call upon completion
449 * @param callback_cls closure for callback
450 * @return NULL on (immediate) errror
452 struct GNUNET_CRYPTO_FileHashContext *
453 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
454 const char *filename, size_t blocksize,
455 GNUNET_CRYPTO_HashCompletedCallback callback,
460 * Cancel a file hashing operation.
462 * @param fhc operation to cancel (callback must not yet have been invoked)
465 GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc);
469 * Create a random hash code.
471 * @param mode desired quality level
472 * @param result hash code that is randomized
475 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
476 GNUNET_HashCode * result);
480 * compute result(delta) = b - a
482 * @param a some hash code
483 * @param b some hash code
484 * @param result set to b - a
487 GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
488 const GNUNET_HashCode * b,
489 GNUNET_HashCode * result);
493 * compute result(b) = a + delta
495 * @param a some hash code
496 * @param delta some hash code
497 * @param result set to a + delta
500 GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
501 const GNUNET_HashCode * delta,
502 GNUNET_HashCode * result);
506 * compute result = a ^ b
508 * @param a some hash code
509 * @param b some hash code
510 * @param result set to a ^ b
513 GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
514 GNUNET_HashCode * result);
518 * Convert a hashcode into a key.
520 * @param hc hash code that serves to generate the key
521 * @param skey set to a valid session key
522 * @param iv set to a valid initialization vector
525 GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
526 struct GNUNET_CRYPTO_AesSessionKey *skey,
527 struct GNUNET_CRYPTO_AesInitializationVector
532 * Obtain a bit from a hashcode.
534 * @param code the GNUNET_CRYPTO_hash to index bit-wise
535 * @param bit index into the hashcode, [0...159]
536 * @return Bit \a bit from hashcode \a code, -1 for invalid index
539 GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit);
542 * Determine how many low order bits match in two
543 * GNUNET_HashCodes. i.e. - 010011 and 011111 share
544 * the first two lowest order bits, and therefore the
545 * return value is two (NOT XOR distance, nor how many
546 * bits match absolutely!).
548 * @param first the first hashcode
549 * @param second the hashcode to compare first to
551 * @return the number of bits that match
554 GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
555 const GNUNET_HashCode * second);
559 * Compare function for HashCodes, producing a total ordering
562 * @param h1 some hash code
563 * @param h2 some hash code
564 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
567 GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2);
571 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
572 * in the XOR metric (Kademlia).
574 * @param h1 some hash code
575 * @param h2 some hash code
576 * @param target some hash code
577 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
580 GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
581 const GNUNET_HashCode * h2,
582 const GNUNET_HashCode * target);
586 * @brief Derive an authentication key
587 * @param key authentication key
588 * @param rkey root key
590 * @param salt_len size of the salt
591 * @param argp pair of void * & size_t for context chunks, terminated by NULL
594 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
595 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
596 const void *salt, size_t salt_len,
601 * @brief Derive an authentication key
602 * @param key authentication key
603 * @param rkey root key
605 * @param salt_len size of the salt
606 * @param ... pair of void * & size_t for context chunks, terminated by NULL
609 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
610 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
611 const void *salt, size_t salt_len, ...);
615 * @param result buffer for the derived key, allocated by caller
616 * @param out_len desired length of the derived key
617 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
618 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
620 * @param xts_len length of xts
621 * @param skm source key material
622 * @param skm_len length of skm
623 * @return GNUNET_YES on success
626 GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
627 const void *xts, size_t xts_len, const void *skm,
628 size_t skm_len, ...);
633 * @param result buffer for the derived key, allocated by caller
634 * @param out_len desired length of the derived key
635 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
636 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
638 * @param xts_len length of xts
639 * @param skm source key material
640 * @param skm_len length of skm
641 * @param argp va_list of void * & size_t pairs for context chunks
642 * @return GNUNET_YES on success
645 GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
646 const void *xts, size_t xts_len, const void *skm,
647 size_t skm_len, va_list argp);
652 * @param result buffer for the derived key, allocated by caller
653 * @param out_len desired length of the derived key
655 * @param xts_len length of xts
656 * @param skm source key material
657 * @param skm_len length of skm
658 * @param argp va_list of void * & size_t pairs for context chunks
659 * @return GNUNET_YES on success
662 GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts,
663 size_t xts_len, const void *skm, size_t skm_len,
669 * @param result buffer for the derived key, allocated by caller
670 * @param out_len desired length of the derived key
672 * @param xts_len length of xts
673 * @param skm source key material
674 * @param skm_len length of skm
675 * @param ... void * & size_t pairs for context chunks
676 * @return GNUNET_YES on success
679 GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts,
680 size_t xts_len, const void *skm, size_t skm_len, ...);
684 * Create a new private key. Caller must free return value.
686 * @return fresh private key
688 struct GNUNET_CRYPTO_RsaPrivateKey *
689 GNUNET_CRYPTO_rsa_key_create (void);
692 * Decode the private key from the data-format back
693 * to the "normal", internal format.
695 * @param buf the buffer where the private key data is stored
696 * @param len the length of the data in 'buffer'
698 struct GNUNET_CRYPTO_RsaPrivateKey *
699 GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len);
702 * Create a new private key by reading it from a file. If the
703 * files does not exist, create a new key and write it to the
704 * file. Caller must free return value. Note that this function
705 * can not guarantee that another process might not be trying
706 * the same operation on the same file at the same time.
707 * If the contents of the file
708 * are invalid the old file is deleted and a fresh key is
711 * @param filename name of file to use for storage
712 * @return new private key, NULL on error (for example,
715 struct GNUNET_CRYPTO_RsaPrivateKey *
716 GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
720 * Deterministically (!) create a private key using only the
721 * given HashCode as input to the PRNG.
723 * @param hc "random" input to PRNG
724 * @return some private key purely dependent on input
726 struct GNUNET_CRYPTO_RsaPrivateKey *
727 GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc);
731 * Free memory occupied by the private key.
732 * @param hostkey pointer to the memory to free
735 GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey);
739 * Extract the public key of the host.
741 * @param priv the private key
742 * @param pub where to write the public key
745 GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey
747 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
752 * Encrypt a block with the public key of another host that uses the
755 * @param block the block to encrypt
756 * @param size the size of block
757 * @param publicKey the encoded public key used to encrypt
758 * @param target where to store the encrypted block
759 * @return GNUNET_SYSERR on error, GNUNET_OK if ok
762 GNUNET_CRYPTO_rsa_encrypt (const void *block, size_t size,
763 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
765 struct GNUNET_CRYPTO_RsaEncryptedData *target);
769 * Decrypt a given block with the hostkey.
771 * @param key the key to use
772 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
773 * @param result pointer to a location where the result can be stored
774 * @param max how many bytes of a result are expected? Must be exact.
775 * @return the size of the decrypted block (that is, size) or -1 on error
778 GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
779 const struct GNUNET_CRYPTO_RsaEncryptedData *block,
780 void *result, size_t max);
784 * Sign a given block.
786 * @param key private key to use for the signing
787 * @param purpose what to sign (size, purpose)
788 * @param sig where to write the signature
789 * @return GNUNET_SYSERR on error, GNUNET_OK on success
792 GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
793 const struct GNUNET_CRYPTO_RsaSignaturePurpose *purpose,
794 struct GNUNET_CRYPTO_RsaSignature *sig);
798 * Verify signature. Note that the caller MUST have already
799 * checked that "validate->size" bytes are actually available.
801 * @param purpose what is the purpose that validate should have?
802 * @param validate block to validate (size, purpose, data)
803 * @param sig signature that is being validated
804 * @param publicKey public key of the signer
805 * @return GNUNET_OK if ok, GNUNET_SYSERR if invalid
808 GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
809 const struct GNUNET_CRYPTO_RsaSignaturePurpose
811 const struct GNUNET_CRYPTO_RsaSignature *sig,
812 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
818 * This function should only be called in testcases
819 * where strong entropy gathering is not desired
820 * (for example, for hostkey generation).
823 GNUNET_CRYPTO_random_disable_entropy_gathering (void);
825 #if 0 /* keep Emacsens' auto-indent happy */
833 /* ifndef GNUNET_CRYPTO_LIB_H */
835 /* end of gnunet_crypto_lib.h */