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 ************* */
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
234 int32_t GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
238 * Produce a random value.
240 * @param mode desired quality of the random number
241 * @param i the upper limit (exclusive) for the random number
242 * @return a random value in the interval [0,i) (exclusive).
244 uint32_t GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
248 * Random on unsigned 64-bit values.
250 * @param mode desired quality of the random number
251 * @param max value returned will be in range [0,max) (exclusive)
252 * @return random 64-bit number
254 uint64_t GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode,
259 * Get an array with a random permutation of the
261 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
262 * @param n the size of the array
263 * @return the permutation array (allocated from heap)
265 unsigned int *GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode,
270 * Create a new Session key.
272 * @param key key to initialize
274 void GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey
278 * Check that a new session key is well-formed.
280 * @param key key to check
281 * @return GNUNET_OK if the key is valid
283 int GNUNET_CRYPTO_aes_check_session_key (const struct
284 GNUNET_CRYPTO_AesSessionKey *key);
288 * Encrypt a block with the public key of another
289 * host that uses the same cyper.
291 * @param block the block to encrypt
292 * @param len the size of the block
293 * @param sessionkey the key used to encrypt
294 * @param iv the initialization vector to use, use INITVALUE
296 * @return the size of the encrypted block, -1 for errors
298 ssize_t GNUNET_CRYPTO_aes_encrypt (const void *block,
300 const struct GNUNET_CRYPTO_AesSessionKey
303 GNUNET_CRYPTO_AesInitializationVector *iv,
308 * Decrypt a given block with the sessionkey.
310 * @param block the data to decrypt, encoded as returned by encrypt
311 * @param size how big is the block?
312 * @param sessionkey the key used to decrypt
313 * @param iv the initialization vector to use
314 * @param result address to store the result at
315 * @return -1 on failure, size of decrypted block on success
317 ssize_t GNUNET_CRYPTO_aes_decrypt (const void *block,
319 const struct GNUNET_CRYPTO_AesSessionKey
322 GNUNET_CRYPTO_AesInitializationVector *iv,
327 * @brief Derive an IV
328 * @param iv initialization vector
329 * @param skey session key
330 * @param salt salt for the derivation
331 * @param salt_len size of the salt
332 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
335 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
336 const struct GNUNET_CRYPTO_AesSessionKey *skey,
337 const void *salt, size_t salt_len, ...);
341 * @brief Derive an IV
342 * @param iv initialization vector
343 * @param skey session key
344 * @param salt salt for the derivation
345 * @param salt_len size of the salt
346 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
349 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
350 const struct GNUNET_CRYPTO_AesSessionKey *skey,
351 const void *salt, size_t salt_len, va_list argp);
355 * Convert hash to ASCII encoding.
356 * @param block the hash code
357 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
358 * safely cast to char*, a '\\0' termination is set).
360 void 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
370 int GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result);
374 * Compute the distance between 2 hashcodes.
375 * The computation must be fast, not involve
376 * a.a or a.e (they're used elsewhere), and
377 * be somewhat consistent. And of course, the
378 * result should be a positive number.
380 * @param a some hash code
381 * @param b some hash code
382 * @return number between 0 and UINT32_MAX
384 uint32_t GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
385 const GNUNET_HashCode * b);
389 * Compute hash of a given block.
391 * @param block the data to hash
392 * @param size size of the block
393 * @param ret pointer to where to write the hashcode
395 void GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret);
399 * Calculate HMAC of a message (RFC 2104)
401 * @param key secret key
402 * @param plaintext input plaintext
403 * @param plaintext_len length of plaintext
404 * @param hmac where to store the hmac
407 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
408 const void *plaintext,
409 size_t plaintext_len, GNUNET_HashCode * hmac);
413 * Function called once the hash computation over the
414 * specified file has completed.
417 * @param res resulting hash, NULL on error
419 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
420 const GNUNET_HashCode *
425 * Handle to file hashing operation.
427 struct GNUNET_CRYPTO_FileHashContext;
430 * Compute the hash of an entire file.
432 * @param priority scheduling priority to use
433 * @param filename name of file to hash
434 * @param blocksize number of bytes to process in one task
435 * @param callback function to call upon completion
436 * @param callback_cls closure for callback
437 * @return NULL on (immediate) errror
439 struct GNUNET_CRYPTO_FileHashContext *GNUNET_CRYPTO_hash_file (enum
440 GNUNET_SCHEDULER_Priority
445 GNUNET_CRYPTO_HashCompletedCallback
452 * Cancel a file hashing operation.
454 * @param fhc operation to cancel (callback must not yet have been invoked)
456 void GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc);
460 * Create a random hash code.
462 * @param mode desired quality level
463 * @param result hash code that is randomized
465 void 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
476 void GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
477 const GNUNET_HashCode * b,
478 GNUNET_HashCode * result);
482 * compute result(b) = a + delta
484 * @param a some hash code
485 * @param delta some hash code
486 * @param result set to a + delta
488 void GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
489 const GNUNET_HashCode * delta,
490 GNUNET_HashCode * result);
494 * compute result = a ^ b
496 * @param a some hash code
497 * @param b some hash code
498 * @param result set to a ^ b
500 void GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a,
501 const GNUNET_HashCode * b,
502 GNUNET_HashCode * result);
506 * Convert a hashcode into a key.
508 * @param hc hash code that serves to generate the key
509 * @param skey set to a valid session key
510 * @param iv set to a valid initialization vector
512 void GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
513 struct GNUNET_CRYPTO_AesSessionKey *skey,
515 GNUNET_CRYPTO_AesInitializationVector *iv);
519 * Obtain a bit from a hashcode.
521 * @param code the GNUNET_CRYPTO_hash to index bit-wise
522 * @param bit index into the hashcode, [0...159]
523 * @return Bit \a bit from hashcode \a code, -1 for invalid index
525 int GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit);
528 * Determine how many low order bits match in two
529 * GNUNET_HashCodes. i.e. - 010011 and 011111 share
530 * the first two lowest order bits, and therefore the
531 * return value is two (NOT XOR distance, nor how many
532 * bits match absolutely!).
534 * @param first the first hashcode
535 * @param second the hashcode to compare first to
537 * @return the number of bits that match
539 unsigned int GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
540 const GNUNET_HashCode * second);
544 * Compare function for HashCodes, producing a total ordering
547 * @param h1 some hash code
548 * @param h2 some hash code
549 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
551 int GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1,
552 const GNUNET_HashCode * h2);
556 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
557 * in the XOR metric (Kademlia).
559 * @param h1 some hash code
560 * @param h2 some hash code
561 * @param target some hash code
562 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
564 int GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
565 const GNUNET_HashCode * h2,
566 const GNUNET_HashCode * target);
570 * @brief Derive an authentication key
571 * @param key authentication key
572 * @param rkey root key
574 * @param salt_len size of the salt
575 * @param argp pair of void * & size_t for context chunks, terminated by NULL
578 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
579 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
581 size_t salt_len, va_list argp);
585 * @brief Derive an authentication key
586 * @param key authentication key
587 * @param rkey root key
589 * @param salt_len size of the salt
590 * @param ... pair of void * & size_t for context chunks, terminated by NULL
593 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
594 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
595 const void *salt, size_t salt_len, ...);
599 * @param result buffer for the derived key, allocated by caller
600 * @param out_len desired length of the derived key
601 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
602 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
604 * @param xts_len length of xts
605 * @param skm source key material
606 * @param skm_len length of skm
607 * @return GNUNET_YES on success
610 GNUNET_CRYPTO_hkdf (void *result,
612 int xtr_algo, int prf_algo,
613 const void *xts, size_t xts_len,
614 const void *skm, size_t skm_len, ...);
619 * @param result buffer for the derived key, allocated by caller
620 * @param out_len desired length of the derived key
621 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
622 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
624 * @param xts_len length of xts
625 * @param skm source key material
626 * @param skm_len length of skm
627 * @param argp va_list of void * & size_t pairs for context chunks
628 * @return GNUNET_YES on success
631 GNUNET_CRYPTO_hkdf_v (void *result,
635 const void *xts, size_t xts_len,
636 const void *skm, size_t skm_len, va_list argp);
641 * @param result buffer for the derived key, allocated by caller
642 * @param out_len desired length of the derived key
644 * @param xts_len length of xts
645 * @param skm source key material
646 * @param skm_len length of skm
647 * @param argp va_list of void * & size_t pairs for context chunks
648 * @return GNUNET_YES on success
651 GNUNET_CRYPTO_kdf_v (void *result,
653 const void *xts, size_t xts_len,
654 const void *skm, size_t skm_len, va_list argp);
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,
670 const void *xts, size_t xts_len, const void *skm,
671 size_t skm_len, ...);
675 * Create a new private key. Caller must free return value.
677 * @return fresh private key
679 struct GNUNET_CRYPTO_RsaPrivateKey *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 *GNUNET_CRYPTO_rsa_decode_key (const char
693 * Create a new private key by reading it from a file. If the
694 * files does not exist, create a new key and write it to the
695 * file. Caller must free return value. Note that this function
696 * can not guarantee that another process might not be trying
697 * the same operation on the same file at the same time.
698 * If the contents of the file
699 * are invalid the old file is deleted and a fresh key is
702 * @param filename name of file to use for storage
703 * @return new private key, NULL on error (for example,
706 struct GNUNET_CRYPTO_RsaPrivateKey
707 *GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
711 * Deterministically (!) create a private key using only the
712 * given HashCode as input to the PRNG.
714 * @param hc "random" input to PRNG
715 * @return some private key purely dependent on input
717 struct GNUNET_CRYPTO_RsaPrivateKey
718 *GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc);
722 * Free memory occupied by the private key.
723 * @param hostkey pointer to the memory to free
725 void 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
734 void GNUNET_CRYPTO_rsa_key_get_public (const struct
735 GNUNET_CRYPTO_RsaPrivateKey *priv,
737 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
751 int GNUNET_CRYPTO_rsa_encrypt (const void *block,
754 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
756 struct GNUNET_CRYPTO_RsaEncryptedData *target);
760 * Decrypt a given block with the hostkey.
762 * @param key the key to use
763 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
764 * @param result pointer to a location where the result can be stored
765 * @param max how many bytes of a result are expected? Must be exact.
766 * @return the size of the decrypted block (that is, size) or -1 on error
768 ssize_t GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey
770 const struct GNUNET_CRYPTO_RsaEncryptedData
771 *block, void *result, size_t max);
775 * Sign a given block.
777 * @param key private key to use for the signing
778 * @param purpose what to sign (size, purpose)
779 * @param sig where to write the signature
780 * @return GNUNET_SYSERR on error, GNUNET_OK on success
782 int GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
783 const struct GNUNET_CRYPTO_RsaSignaturePurpose
784 *purpose, 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
797 int GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
798 const struct GNUNET_CRYPTO_RsaSignaturePurpose
800 const struct GNUNET_CRYPTO_RsaSignature *sig,
802 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).
812 void GNUNET_CRYPTO_random_disable_entropy_gathering (void);
814 #if 0 /* keep Emacsens' auto-indent happy */
822 /* ifndef GNUNET_CRYPTO_LIB_H */
824 /* end of gnunet_crypto_lib.h */