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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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);
238 * Perform an incremental step in a CRC16 (for TCP/IP) calculation.
240 * @param sum current sum, initially 0
241 * @param buf buffer to calculate CRC over (must be 16-bit aligned)
242 * @param len number of bytes in hdr, must be multiple of 2
243 * @return updated crc sum (must be subjected to GNUNET_CRYPTO_crc16_finish to get actual crc16)
246 GNUNET_CRYPTO_crc16_step (uint32_t sum, const void *buf, size_t len);
250 * Convert results from GNUNET_CRYPTO_crc16_step to final crc16.
252 * @param sum cummulative sum
253 * @return crc16 value
256 GNUNET_CRYPTO_crc16_finish (uint32_t sum);
260 * Calculate the checksum of a buffer in one step.
262 * @param buf buffer to calculate CRC over (must be 16-bit aligned)
263 * @param len number of bytes in hdr, must be multiple of 2
264 * @return crc16 value
267 GNUNET_CRYPTO_crc16_n (const void *buf, size_t len);
271 * Compute the CRC32 checksum for the first len
272 * bytes of the buffer.
274 * @param buf the data over which we're taking the CRC
275 * @param len the length of the buffer in bytes
276 * @return the resulting CRC32 checksum
279 GNUNET_CRYPTO_crc32_n (const void *buf, size_t len);
283 * Produce a random value.
285 * @param mode desired quality of the random number
286 * @param i the upper limit (exclusive) for the random number
287 * @return a random value in the interval [0,i) (exclusive).
290 GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i);
294 * Random on unsigned 64-bit values.
296 * @param mode desired quality of the random number
297 * @param max value returned will be in range [0,max) (exclusive)
298 * @return random 64-bit number
301 GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max);
305 * Get an array with a random permutation of the
307 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
308 * @param n the size of the array
309 * @return the permutation array (allocated from heap)
312 GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n);
316 * Create a new Session key.
318 * @param key key to initialize
321 GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key);
324 * Check that a new session key is well-formed.
326 * @param key key to check
327 * @return GNUNET_OK if the key is valid
330 GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey
335 * Encrypt a block with the public key of another
336 * host that uses the same cyper.
338 * @param block the block to encrypt
339 * @param len the size of the block
340 * @param sessionkey the key used to encrypt
341 * @param iv the initialization vector to use, use INITVALUE
343 * @return the size of the encrypted block, -1 for errors
346 GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len,
347 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
348 const struct GNUNET_CRYPTO_AesInitializationVector
353 * Decrypt a given block with the sessionkey.
355 * @param block the data to decrypt, encoded as returned by encrypt
356 * @param size how big is the block?
357 * @param sessionkey the key used to decrypt
358 * @param iv the initialization vector to use
359 * @param result address to store the result at
360 * @return -1 on failure, size of decrypted block on success
363 GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size,
364 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
365 const struct GNUNET_CRYPTO_AesInitializationVector
370 * @brief Derive an IV
371 * @param iv initialization vector
372 * @param skey session key
373 * @param salt salt for the derivation
374 * @param salt_len size of the salt
375 * @param ... pairs of void * & size_t for context chunks, terminated by NULL
378 GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv,
379 const struct GNUNET_CRYPTO_AesSessionKey *skey,
380 const void *salt, size_t salt_len, ...);
384 * @brief Derive an IV
385 * @param iv initialization vector
386 * @param skey session key
387 * @param salt salt for the derivation
388 * @param salt_len size of the salt
389 * @param argp pairs of void * & size_t for context chunks, terminated by NULL
392 GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv,
393 const struct GNUNET_CRYPTO_AesSessionKey *skey,
394 const void *salt, size_t salt_len, va_list argp);
398 * Convert hash to ASCII encoding.
399 * @param block the hash code
400 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
401 * safely cast to char*, a '\\0' termination is set).
404 GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
405 struct GNUNET_CRYPTO_HashAsciiEncoded *result);
409 * Convert ASCII encoding back to GNUNET_CRYPTO_hash
410 * @param enc the encoding
411 * @param result where to store the GNUNET_CRYPTO_hash code
412 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
415 GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result);
419 * Compute the distance between 2 hashcodes.
420 * The computation must be fast, not involve
421 * a.a or a.e (they're used elsewhere), and
422 * be somewhat consistent. And of course, the
423 * result should be a positive number.
425 * @param a some hash code
426 * @param b some hash code
427 * @return number between 0 and UINT32_MAX
430 GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
431 const GNUNET_HashCode * b);
435 * Compute hash of a given block.
437 * @param block the data to hash
438 * @param size size of the block
439 * @param ret pointer to where to write the hashcode
442 GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret);
446 * Calculate HMAC of a message (RFC 2104)
448 * @param key secret key
449 * @param plaintext input plaintext
450 * @param plaintext_len length of plaintext
451 * @param hmac where to store the hmac
454 GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
455 const void *plaintext, size_t plaintext_len,
456 GNUNET_HashCode * hmac);
460 * Function called once the hash computation over the
461 * specified file has completed.
464 * @param res resulting hash, NULL on error
466 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
467 const GNUNET_HashCode *
472 * Handle to file hashing operation.
474 struct GNUNET_CRYPTO_FileHashContext;
477 * Compute the hash of an entire file.
479 * @param priority scheduling priority to use
480 * @param filename name of file to hash
481 * @param blocksize number of bytes to process in one task
482 * @param callback function to call upon completion
483 * @param callback_cls closure for callback
484 * @return NULL on (immediate) errror
486 struct GNUNET_CRYPTO_FileHashContext *
487 GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
488 const char *filename, size_t blocksize,
489 GNUNET_CRYPTO_HashCompletedCallback callback,
494 * Cancel a file hashing operation.
496 * @param fhc operation to cancel (callback must not yet have been invoked)
499 GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc);
503 * Create a random hash code.
505 * @param mode desired quality level
506 * @param result hash code that is randomized
509 GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
510 GNUNET_HashCode * result);
514 * compute result(delta) = b - a
516 * @param a some hash code
517 * @param b some hash code
518 * @param result set to b - a
521 GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
522 const GNUNET_HashCode * b,
523 GNUNET_HashCode * result);
527 * compute result(b) = a + delta
529 * @param a some hash code
530 * @param delta some hash code
531 * @param result set to a + delta
534 GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
535 const GNUNET_HashCode * delta,
536 GNUNET_HashCode * result);
540 * compute result = a ^ b
542 * @param a some hash code
543 * @param b some hash code
544 * @param result set to a ^ b
547 GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b,
548 GNUNET_HashCode * result);
552 * Convert a hashcode into a key.
554 * @param hc hash code that serves to generate the key
555 * @param skey set to a valid session key
556 * @param iv set to a valid initialization vector
559 GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
560 struct GNUNET_CRYPTO_AesSessionKey *skey,
561 struct GNUNET_CRYPTO_AesInitializationVector
566 * Obtain a bit from a hashcode.
568 * @param code the GNUNET_CRYPTO_hash to index bit-wise
569 * @param bit index into the hashcode, [0...159]
570 * @return Bit \a bit from hashcode \a code, -1 for invalid index
573 GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit);
576 * Determine how many low order bits match in two
577 * GNUNET_HashCodes. i.e. - 010011 and 011111 share
578 * the first two lowest order bits, and therefore the
579 * return value is two (NOT XOR distance, nor how many
580 * bits match absolutely!).
582 * @param first the first hashcode
583 * @param second the hashcode to compare first to
585 * @return the number of bits that match
588 GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first,
589 const GNUNET_HashCode * second);
593 * Compare function for HashCodes, producing a total ordering
596 * @param h1 some hash code
597 * @param h2 some hash code
598 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
601 GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2);
605 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
606 * in the XOR metric (Kademlia).
608 * @param h1 some hash code
609 * @param h2 some hash code
610 * @param target some hash code
611 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
614 GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
615 const GNUNET_HashCode * h2,
616 const GNUNET_HashCode * target);
620 * @brief Derive an authentication key
621 * @param key authentication key
622 * @param rkey root key
624 * @param salt_len size of the salt
625 * @param argp pair of void * & size_t for context chunks, terminated by NULL
628 GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
629 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
630 const void *salt, size_t salt_len,
635 * @brief Derive an authentication key
636 * @param key authentication key
637 * @param rkey root key
639 * @param salt_len size of the salt
640 * @param ... pair of void * & size_t for context chunks, terminated by NULL
643 GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
644 const struct GNUNET_CRYPTO_AesSessionKey *rkey,
645 const void *salt, size_t salt_len, ...);
649 * @param result buffer for the derived key, allocated by caller
650 * @param out_len desired length of the derived key
651 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
652 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
654 * @param xts_len length of xts
655 * @param skm source key material
656 * @param skm_len length of skm
657 * @return GNUNET_YES on success
660 GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo,
661 const void *xts, size_t xts_len, const void *skm,
662 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
669 * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_...
670 * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_...
672 * @param xts_len length of xts
673 * @param skm source key material
674 * @param skm_len length of skm
675 * @param argp va_list of void * & size_t pairs for context chunks
676 * @return GNUNET_YES on success
679 GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo,
680 const void *xts, size_t xts_len, const void *skm,
681 size_t skm_len, va_list argp);
686 * @param result buffer for the derived key, allocated by caller
687 * @param out_len desired length of the derived key
689 * @param xts_len length of xts
690 * @param skm source key material
691 * @param skm_len length of skm
692 * @param argp va_list of void * & size_t pairs for context chunks
693 * @return GNUNET_YES on success
696 GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts,
697 size_t xts_len, const void *skm, size_t skm_len,
703 * @param result buffer for the derived key, allocated by caller
704 * @param out_len desired length of the derived key
706 * @param xts_len length of xts
707 * @param skm source key material
708 * @param skm_len length of skm
709 * @param ... void * & size_t pairs for context chunks
710 * @return GNUNET_YES on success
713 GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts,
714 size_t xts_len, const void *skm, size_t skm_len, ...);
718 * Create a new private key. Caller must free return value.
720 * @return fresh private key
722 struct GNUNET_CRYPTO_RsaPrivateKey *
723 GNUNET_CRYPTO_rsa_key_create (void);
726 * Decode the private key from the data-format back
727 * to the "normal", internal format.
729 * @param buf the buffer where the private key data is stored
730 * @param len the length of the data in 'buffer'
732 struct GNUNET_CRYPTO_RsaPrivateKey *
733 GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len);
736 * Create a new private key by reading it from a file. If the
737 * files does not exist, create a new key and write it to the
738 * file. Caller must free return value. Note that this function
739 * can not guarantee that another process might not be trying
740 * the same operation on the same file at the same time.
741 * If the contents of the file
742 * are invalid the old file is deleted and a fresh key is
745 * @param filename name of file to use for storage
746 * @return new private key, NULL on error (for example,
749 struct GNUNET_CRYPTO_RsaPrivateKey *
750 GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
754 * Deterministically (!) create a private key using only the
755 * given HashCode as input to the PRNG.
757 * @param hc "random" input to PRNG
758 * @return some private key purely dependent on input
760 struct GNUNET_CRYPTO_RsaPrivateKey *
761 GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc);
765 * Free memory occupied by the private key.
766 * @param hostkey pointer to the memory to free
769 GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey);
773 * Extract the public key of the host.
775 * @param priv the private key
776 * @param pub where to write the public key
779 GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey
781 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
786 * Encrypt a block with the public key of another host that uses the
789 * @param block the block to encrypt
790 * @param size the size of block
791 * @param publicKey the encoded public key used to encrypt
792 * @param target where to store the encrypted block
793 * @return GNUNET_SYSERR on error, GNUNET_OK if ok
796 GNUNET_CRYPTO_rsa_encrypt (const void *block, size_t size,
797 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
799 struct GNUNET_CRYPTO_RsaEncryptedData *target);
803 * Decrypt a given block with the hostkey.
805 * @param key the key to use
806 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
807 * @param result pointer to a location where the result can be stored
808 * @param max how many bytes of a result are expected? Must be exact.
809 * @return the size of the decrypted block (that is, size) or -1 on error
812 GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
813 const struct GNUNET_CRYPTO_RsaEncryptedData *block,
814 void *result, size_t max);
818 * Sign a given block.
820 * @param key private key to use for the signing
821 * @param purpose what to sign (size, purpose)
822 * @param sig where to write the signature
823 * @return GNUNET_SYSERR on error, GNUNET_OK on success
826 GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
827 const struct GNUNET_CRYPTO_RsaSignaturePurpose *purpose,
828 struct GNUNET_CRYPTO_RsaSignature *sig);
832 * Verify signature. Note that the caller MUST have already
833 * checked that "validate->size" bytes are actually available.
835 * @param purpose what is the purpose that validate should have?
836 * @param validate block to validate (size, purpose, data)
837 * @param sig signature that is being validated
838 * @param publicKey public key of the signer
839 * @return GNUNET_OK if ok, GNUNET_SYSERR if invalid
842 GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
843 const struct GNUNET_CRYPTO_RsaSignaturePurpose
845 const struct GNUNET_CRYPTO_RsaSignature *sig,
846 const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
852 * This function should only be called in testcases
853 * where strong entropy gathering is not desired
854 * (for example, for hostkey generation).
857 GNUNET_CRYPTO_random_disable_entropy_gathering (void);
859 #if 0 /* keep Emacsens' auto-indent happy */
867 /* ifndef GNUNET_CRYPTO_LIB_H */
869 /* end of gnunet_crypto_lib.h */