2 This file is part of GNUnet.
3 (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
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12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
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17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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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 ************* */
227 * Compute the CRC32 checksum for the first len
228 * bytes of the buffer.
230 * @param buf the data over which we're taking the CRC
231 * @param len the length of the buffer in bytes
232 * @return the resulting CRC32 checksum
235 GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
239 * Produce a random value.
241 * @param mode desired quality of the random number
242 * @param i the upper limit (exclusive) for the random number
243 * @return a random value in the interval [0,i) (exclusive).
246 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
250 * Random on unsigned 64-bit values.
252 * @param mode desired quality of the random number
253 * @param max value returned will be in range [0,max) (exclusive)
254 * @return random 64-bit number
257 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max);
261 * Get an array with a random permutation of the
263 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
264 * @param n the size of the array
265 * @return the permutation array (allocated from heap)
268 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n);
272 * Create a new Session key.
274 * @param key key to initialize
277 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key);
280 * Check that a new session key is well-formed.
282 * @param key key to check
283 * @return GNUNET_OK if the key is valid
286 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
291 * Encrypt a block with the public key of another
292 * host that uses the same cyper.
294 * @param block the block to encrypt
295 * @param len the size of the block
296 * @param sessionkey the key used to encrypt
297 * @param iv the initialization vector to use, use INITVALUE
299 * @return the size of the encrypted block, -1 for errors
302 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
303 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
304 const struct GNUNET_CRYPTO_AesInitializationVector
309 * Decrypt a given block with the sessionkey.
311 * @param block the data to decrypt, encoded as returned by encrypt
312 * @param size how big is the block?
313 * @param sessionkey the key used to decrypt
314 * @param iv the initialization vector to use
315 * @param result address to store the result at
316 * @return -1 on failure, size of decrypted block on success
319 GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size,
320 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
321 const struct GNUNET_CRYPTO_AesInitializationVector
326 * @brief Derive an IV
327 * @param iv initialization vector
328 * @param skey session key
329 * @param salt salt for the derivation
330 * @param salt_len size of the salt
331 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
334 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
335 const struct GNUNET_CRYPTO_AesSessionKey *skey,
336 const void *salt, size_t salt_len, ...);
340 * @brief Derive an IV
341 * @param iv initialization vector
342 * @param skey session key
343 * @param salt salt for the derivation
344 * @param salt_len size of the salt
345 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
348 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
349 const struct GNUNET_CRYPTO_AesSessionKey *skey,
350 const void *salt, size_t salt_len, va_list argp);
354 * Convert hash to ASCII encoding.
355 * @param block the hash code
356 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
357 * safely cast to char*, a '\\0' termination is set).
360 GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
361 struct GNUNET_CRYPTO_HashAsciiEncoded *result);
365 * Convert ASCII encoding back to GNUNET_CRYPTO_hash
366 * @param enc the encoding
367 * @param result where to store the GNUNET_CRYPTO_hash code
368 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
371 GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result);
375 * Compute the distance between 2 hashcodes.
376 * The computation must be fast, not involve
377 * a.a or a.e (they're used elsewhere), and
378 * be somewhat consistent. And of course, the
379 * result should be a positive number.
381 * @param a some hash code
382 * @param b some hash code
383 * @return number between 0 and UINT32_MAX
386 GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
387 const GNUNET_HashCode * b);
391 * Compute hash of a given block.
393 * @param block the data to hash
394 * @param size size of the block
395 * @param ret pointer to where to write the hashcode
398 GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret);
402 * Calculate HMAC of a message (RFC 2104)
404 * @param key secret key
405 * @param plaintext input plaintext
406 * @param plaintext_len length of plaintext
407 * @param hmac where to store the hmac
410 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
411 const void *plaintext, size_t plaintext_len,
412 GNUNET_HashCode * hmac);
416 * Function called once the hash computation over the
417 * specified file has completed.
420 * @param res resulting hash, NULL on error
422 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
423 const GNUNET_HashCode *
428 * Handle to file hashing operation.
430 struct GNUNET_CRYPTO_FileHashContext;
433 * Compute the hash of an entire file.
435 * @param priority scheduling priority to use
436 * @param filename name of file to hash
437 * @param blocksize number of bytes to process in one task
438 * @param callback function to call upon completion
439 * @param callback_cls closure for callback
440 * @return NULL on (immediate) errror
442 struct GNUNET_CRYPTO_FileHashContext *
443 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
444 const char *filename, size_t blocksize,
445 GNUNET_CRYPTO_HashCompletedCallback callback,
450 * Cancel a file hashing operation.
452 * @param fhc operation to cancel (callback must not yet have been invoked)
455 GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc);
459 * Create a random hash code.
461 * @param mode desired quality level
462 * @param result hash code that is randomized
465 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
466 GNUNET_HashCode * result);
470 * compute result(delta) = b - a
472 * @param a some hash code
473 * @param b some hash code
474 * @param result set to b - a
477 GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
478 const GNUNET_HashCode * b,
479 GNUNET_HashCode * result);
483 * compute result(b) = a + delta
485 * @param a some hash code
486 * @param delta some hash code
487 * @param result set to a + delta
490 GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
491 const GNUNET_HashCode * delta,
492 GNUNET_HashCode * result);
496 * compute result = a ^ b
498 * @param a some hash code
499 * @param b some hash code
500 * @param result set to a ^ b
503 GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
504 GNUNET_HashCode * result);
508 * Convert a hashcode into a key.
510 * @param hc hash code that serves to generate the key
511 * @param skey set to a valid session key
512 * @param iv set to a valid initialization vector
515 GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
516 struct GNUNET_CRYPTO_AesSessionKey *skey,
517 struct GNUNET_CRYPTO_AesInitializationVector
522 * Obtain a bit from a hashcode.
524 * @param code the GNUNET_CRYPTO_hash to index bit-wise
525 * @param bit index into the hashcode, [0...159]
526 * @return Bit \a bit from hashcode \a code, -1 for invalid index
529 GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit);
532 * Determine how many low order bits match in two
533 * GNUNET_HashCodes. i.e. - 010011 and 011111 share
534 * the first two lowest order bits, and therefore the
535 * return value is two (NOT XOR distance, nor how many
536 * bits match absolutely!).
538 * @param first the first hashcode
539 * @param second the hashcode to compare first to
541 * @return the number of bits that match
544 GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
545 const GNUNET_HashCode * second);
549 * Compare function for HashCodes, producing a total ordering
552 * @param h1 some hash code
553 * @param h2 some hash code
554 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
557 GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2);
561 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
562 * in the XOR metric (Kademlia).
564 * @param h1 some hash code
565 * @param h2 some hash code
566 * @param target some hash code
567 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
570 GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
571 const GNUNET_HashCode * h2,
572 const GNUNET_HashCode * target);
576 * @brief Derive an authentication key
577 * @param key authentication key
578 * @param rkey root key
580 * @param salt_len size of the salt
581 * @param argp pair of void * & size_t for context chunks, terminated by NULL
584 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
585 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
586 const void *salt, size_t salt_len,
591 * @brief Derive an authentication key
592 * @param key authentication key
593 * @param rkey root key
595 * @param salt_len size of the salt
596 * @param ... pair of void * & size_t for context chunks, terminated by NULL
599 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
600 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
601 const void *salt, size_t salt_len, ...);
605 * @param result buffer for the derived key, allocated by caller
606 * @param out_len desired length of the derived key
607 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
608 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
610 * @param xts_len length of xts
611 * @param skm source key material
612 * @param skm_len length of skm
613 * @return GNUNET_YES on success
616 GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
617 const void *xts, size_t xts_len, const void *skm,
618 size_t skm_len, ...);
623 * @param result buffer for the derived key, allocated by caller
624 * @param out_len desired length of the derived key
625 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
626 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
628 * @param xts_len length of xts
629 * @param skm source key material
630 * @param skm_len length of skm
631 * @param argp va_list of void * & size_t pairs for context chunks
632 * @return GNUNET_YES on success
635 GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
636 const void *xts, size_t xts_len, const void *skm,
637 size_t skm_len, va_list argp);
642 * @param result buffer for the derived key, allocated by caller
643 * @param out_len desired length of the derived key
645 * @param xts_len length of xts
646 * @param skm source key material
647 * @param skm_len length of skm
648 * @param argp va_list of void * & size_t pairs for context chunks
649 * @return GNUNET_YES on success
652 GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts,
653 size_t xts_len, const void *skm, size_t skm_len,
659 * @param result buffer for the derived key, allocated by caller
660 * @param out_len desired length of the derived key
662 * @param xts_len length of xts
663 * @param skm source key material
664 * @param skm_len length of skm
665 * @param ... void * & size_t pairs for context chunks
666 * @return GNUNET_YES on success
669 GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts,
670 size_t xts_len, const void *skm, size_t skm_len, ...);
674 * Create a new private key. Caller must free return value.
676 * @return fresh private key
678 struct GNUNET_CRYPTO_RsaPrivateKey *
679 GNUNET_CRYPTO_rsa_key_create (void);
682 * Decode the private key from the data-format back
683 * to the "normal", internal format.
685 * @param buf the buffer where the private key data is stored
686 * @param len the length of the data in 'buffer'
688 struct GNUNET_CRYPTO_RsaPrivateKey *
689 GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len);
692 * Create a new private key by reading it from a file. If the
693 * files does not exist, create a new key and write it to the
694 * file. Caller must free return value. Note that this function
695 * can not guarantee that another process might not be trying
696 * the same operation on the same file at the same time.
697 * If the contents of the file
698 * are invalid the old file is deleted and a fresh key is
701 * @param filename name of file to use for storage
702 * @return new private key, NULL on error (for example,
705 struct GNUNET_CRYPTO_RsaPrivateKey *
706 GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
710 * Deterministically (!) create a private key using only the
711 * given HashCode as input to the PRNG.
713 * @param hc "random" input to PRNG
714 * @return some private key purely dependent on input
716 struct GNUNET_CRYPTO_RsaPrivateKey *
717 GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc);
721 * Free memory occupied by the private key.
722 * @param hostkey pointer to the memory to free
725 GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey);
729 * Extract the public key of the host.
731 * @param priv the private key
732 * @param pub where to write the public key
735 GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey
737 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
742 * Encrypt a block with the public key of another host that uses the
745 * @param block the block to encrypt
746 * @param size the size of block
747 * @param publicKey the encoded public key used to encrypt
748 * @param target where to store the encrypted block
749 * @return GNUNET_SYSERR on error, GNUNET_OK if ok
752 GNUNET_CRYPTO_rsa_encrypt (const void *block, size_t size,
753 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
755 struct GNUNET_CRYPTO_RsaEncryptedData *target);
759 * Decrypt a given block with the hostkey.
761 * @param key the key to use
762 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
763 * @param result pointer to a location where the result can be stored
764 * @param max how many bytes of a result are expected? Must be exact.
765 * @return the size of the decrypted block (that is, size) or -1 on error
768 GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
769 const struct GNUNET_CRYPTO_RsaEncryptedData *block,
770 void *result, size_t max);
774 * Sign a given block.
776 * @param key private key to use for the signing
777 * @param purpose what to sign (size, purpose)
778 * @param sig where to write the signature
779 * @return GNUNET_SYSERR on error, GNUNET_OK on success
782 GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
783 const struct GNUNET_CRYPTO_RsaSignaturePurpose *purpose,
784 struct GNUNET_CRYPTO_RsaSignature *sig);
788 * Verify signature. Note that the caller MUST have already
789 * checked that "validate->size" bytes are actually available.
791 * @param purpose what is the purpose that validate should have?
792 * @param validate block to validate (size, purpose, data)
793 * @param sig signature that is being validated
794 * @param publicKey public key of the signer
795 * @return GNUNET_OK if ok, GNUNET_SYSERR if invalid
798 GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
799 const struct GNUNET_CRYPTO_RsaSignaturePurpose
801 const struct GNUNET_CRYPTO_RsaSignature *sig,
802 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
808 * This function should only be called in testcases
809 * where strong entropy gathering is not desired
810 * (for example, for hostkey generation).
813 GNUNET_CRYPTO_random_disable_entropy_gathering (void);
815 #if 0 /* keep Emacsens' auto-indent happy */
823 /* ifndef GNUNET_CRYPTO_LIB_H */
825 /* end of gnunet_crypto_lib.h */