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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
65 * @brief length of the sessionkey in bytes (256 BIT sessionkey)
67 #define GNUNET_CRYPTO_AES_KEY_LENGTH (256/8)
71 * @brief Length of RSA encrypted data (2048 bit)
73 * We currently do not handle encryption of data
74 * that can not be done in a single call to the
75 * RSA methods (read: large chunks of data).
76 * We should never need that, as we can use
77 * the GNUNET_CRYPTO_hash for larger pieces of data for signing,
78 * and for encryption, we only need to encode sessionkeys!
80 #define GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH 256
84 * Length of an RSA KEY (d,e,len), 2048 bit (=256 octests) key d, 2 byte e
86 #define GNUNET_CRYPTO_RSA_KEY_LENGTH 258
90 * The private information of an RSA key pair.
92 struct GNUNET_CRYPTO_RsaPrivateKey;
96 * @brief 0-terminated ASCII encoding of a GNUNET_HashCode.
98 struct GNUNET_CRYPTO_HashAsciiEncoded
100 unsigned char encoding[104];
106 * @brief an RSA signature
108 struct GNUNET_CRYPTO_RsaSignature
110 unsigned char sig[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH];
115 * @brief header of what an RSA signature signs
116 * this must be followed by "size - 8" bytes of
117 * the actual signed data
119 struct GNUNET_CRYPTO_RsaSignaturePurpose
122 * How many bytes does this signature sign?
123 * (including this purpose header); in network
126 uint32_t size GNUNET_PACKED;
129 * What does this signature vouch for? This
130 * must contain a GNUNET_SIGNATURE_PURPOSE_XXX
131 * constant (from gnunet_signatures.h). In
132 * network byte order!
134 uint32_t purpose GNUNET_PACKED;
140 * @brief A public key.
142 struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
145 * In big-endian, must be GNUNET_CRYPTO_RSA_KEY_LENGTH+4
147 uint16_t len GNUNET_PACKED;
150 * Size of n in key; in big-endian!
152 uint16_t sizen GNUNET_PACKED;
155 * The key itself, contains n followed by e.
157 unsigned char key[GNUNET_CRYPTO_RSA_KEY_LENGTH];
160 * Padding (must be 0)
162 uint16_t padding GNUNET_PACKED;
167 * RSA Encrypted data.
169 struct GNUNET_CRYPTO_RsaEncryptedData
171 unsigned char encoding[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH];
176 * @brief type for session keys
178 struct GNUNET_CRYPTO_AesSessionKey
183 unsigned char key[GNUNET_CRYPTO_AES_KEY_LENGTH];
188 uint32_t crc32 GNUNET_PACKED;
193 * @brief IV for sym cipher
195 * NOTE: must be smaller (!) in size than the
198 struct GNUNET_CRYPTO_AesInitializationVector
200 unsigned char iv[GNUNET_CRYPTO_AES_KEY_LENGTH / 2];
204 /* **************** Functions and Macros ************* */
208 * Compute the CRC32 checksum for the first len
209 * bytes of the buffer.
211 * @param buf the data over which we're taking the CRC
212 * @param len the length of the buffer in bytes
213 * @return the resulting CRC32 checksum
215 int32_t GNUNET_CRYPTO_crc32_n (const void *buf,
220 * Produce a random value.
222 * @param mode desired quality of the random number
223 * @param i the upper limit (exclusive) for the random number
224 * @return a random value in the interval [0,i) (exclusive).
226 uint32_t GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode,
231 * Random on unsigned 64-bit values. We break them down into signed
232 * 32-bit values and reassemble the 64-bit random value bit-wise.
234 * @param mode desired quality of the random number
235 * @param max value returned will be in range [0,max) (exclusive)
236 * @return random 64-bit number
238 uint64_t GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode,
243 * Get an array with a random permutation of the
245 * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise
246 * @param n the size of the array
247 * @return the permutation array (allocated from heap)
249 unsigned int *GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode,
254 * Create a new Session key.
256 * @param key key to initialize
258 void GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey
263 * Check that a new session key is well-formed.
265 * @param key key to check
266 * @return GNUNET_OK if the key is valid
268 int GNUNET_CRYPTO_aes_check_session_key (const struct
269 GNUNET_CRYPTO_AesSessionKey *key);
273 * Encrypt a block with the public key of another
274 * host that uses the same cyper.
276 * @param block the block to encrypt
277 * @param len the size of the block
278 * @param sessionkey the key used to encrypt
279 * @param iv the initialization vector to use, use INITVALUE
281 * @returns the size of the encrypted block, -1 for errors
283 ssize_t GNUNET_CRYPTO_aes_encrypt (const void *block,
285 const struct GNUNET_CRYPTO_AesSessionKey
288 GNUNET_CRYPTO_AesInitializationVector *iv,
293 * Decrypt a given block with the sessionkey.
295 * @param block the data to decrypt, encoded as returned by encrypt
296 * @param size how big is the block?
297 * @param sessionkey the key used to decrypt
298 * @param iv the initialization vector to use
299 * @param result address to store the result at
300 * @return -1 on failure, size of decrypted block on success
302 ssize_t GNUNET_CRYPTO_aes_decrypt (const void *block,
304 const struct GNUNET_CRYPTO_AesSessionKey *sessionkey,
305 const struct GNUNET_CRYPTO_AesInitializationVector *iv,
310 * Convert GNUNET_CRYPTO_hash to ASCII encoding.
311 * @param block the GNUNET_CRYPTO_hash code
312 * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be
313 * safely cast to char*, a '\0' termination is set).
315 void GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block,
316 struct GNUNET_CRYPTO_HashAsciiEncoded
321 * Convert ASCII encoding back to GNUNET_CRYPTO_hash
322 * @param enc the encoding
323 * @param result where to store the GNUNET_CRYPTO_hash code
324 * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding
326 int GNUNET_CRYPTO_hash_from_string (const char *enc,
327 GNUNET_HashCode * result);
331 * Compute the distance between 2 hashcodes.
332 * The computation must be fast, not involve
333 * a.a or a.e (they're used elsewhere), and
334 * be somewhat consistent. And of course, the
335 * result should be a positive number.
337 * @param a some hash code
338 * @param b some hash code
339 * @return number between 0 and 65536
341 uint32_t GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a,
342 const GNUNET_HashCode * b);
346 * Compute hash of a given block.
348 * @param block the data to hash
349 * @param size size of the block
350 * @param ret pointer to where to write the hashcode
352 void GNUNET_CRYPTO_hash (const void *block,
354 GNUNET_HashCode * ret);
358 * Function called once the hash computation over the
359 * specified file has completed.
362 * @param res resulting hash, NULL on error
364 typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls,
365 const GNUNET_HashCode *
370 * Compute the hash of an entire file.
372 * @param sched scheduler to use
373 * @param priority scheduling priority to use
374 * @param run_on_shutdown should we complete even on shutdown?
375 * @param filename name of file to hash
376 * @param blocksize number of bytes to process in one task
377 * @param callback function to call upon completion
378 * @param callback_cls closure for callback
380 void GNUNET_CRYPTO_hash_file (struct GNUNET_SCHEDULER_Handle *sched,
381 enum GNUNET_SCHEDULER_Priority priority,
383 const char *filename,
385 GNUNET_CRYPTO_HashCompletedCallback callback,
390 * Create a random hash code.
392 * @param mode desired quality level
393 * @param result hash code that is randomized
395 void GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
396 GNUNET_HashCode * result);
400 * compute result(delta) = b - a
402 * @param a some hash code
403 * @param b some hash code
404 * @param result set to b - a
406 void GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a,
407 const GNUNET_HashCode * b,
408 GNUNET_HashCode * result);
412 * compute result(b) = a + delta
414 * @param a some hash code
415 * @param delta some hash code
416 * @param result set to a + delta
418 void GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a,
419 const GNUNET_HashCode * delta,
420 GNUNET_HashCode * result);
424 * compute result = a ^ b
426 * @param a some hash code
427 * @param b some hash code
428 * @param result set to a ^ b
430 void GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a,
431 const GNUNET_HashCode * b,
432 GNUNET_HashCode * result);
436 * Convert a hashcode into a key.
438 * @param hc hash code that serves to generate the key
439 * @param skey set to a valid session key
440 * @param iv set to a valid initialization vector
442 void GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc,
443 struct GNUNET_CRYPTO_AesSessionKey *skey,
445 GNUNET_CRYPTO_AesInitializationVector
450 * Obtain a bit from a hashcode.
452 * @param code the GNUNET_CRYPTO_hash to index bit-wise
453 * @param bit index into the hashcode, [0...159]
454 * @return Bit \a bit from hashcode \a code, -1 for invalid index
456 int GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code,
461 * Compare function for HashCodes, producing a total ordering
464 * @param h1 some hash code
465 * @param h2 some hash code
466 * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
468 int GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1,
469 const GNUNET_HashCode * h2);
473 * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target
474 * in the XOR metric (Kademlia).
476 * @param h1 some hash code
477 * @param h2 some hash code
478 * @param target some hash code
479 * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
481 int GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1,
482 const GNUNET_HashCode * h2,
483 const GNUNET_HashCode * target);
487 * Create a new private key. Caller must free return value.
489 * @return fresh private key
491 struct GNUNET_CRYPTO_RsaPrivateKey *GNUNET_CRYPTO_rsa_key_create (void);
495 * Create a new private key by reading it from a file. If the
496 * files does not exist, create a new key and write it to the
497 * file. Caller must free return value. Note that this function
498 * can not guarantee that another process might not be trying
499 * the same operation on the same file at the same time. The
500 * caller must somehow know that the file either already exists
501 * with a valid key OR be sure that no other process is calling
502 * this function at the same time. If the contents of the file
503 * are invalid the old file is deleted and a fresh key is
506 * @param filename name of file to use for storage
507 * @return new private key, NULL on error (for example,
510 struct GNUNET_CRYPTO_RsaPrivateKey
511 *GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename);
515 * Deterministically (!) create a private key using only the
516 * given HashCode as input to the PRNG.
518 * @param input "random" input to PRNG
519 * @return some private key purely dependent on input
521 struct GNUNET_CRYPTO_RsaPrivateKey
522 *GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * input);
526 * Free memory occupied by the private key.
527 * @param hostkey pointer to the memory to free
529 void GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey);
533 * Extract the public key of the host.
535 * @param priv the private key
536 * @param pub where to write the public key
538 void GNUNET_CRYPTO_rsa_key_get_public (const struct
539 GNUNET_CRYPTO_RsaPrivateKey *priv,
541 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
546 * Encrypt a block with the public key of another host that uses the
549 * @param block the block to encrypt
550 * @param size the size of block
551 * @param publicKey the encoded public key used to encrypt
552 * @param target where to store the encrypted block
553 * @returns GNUNET_SYSERR on error, GNUNET_OK if ok
555 int GNUNET_CRYPTO_rsa_encrypt (const void *block,
558 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
560 struct GNUNET_CRYPTO_RsaEncryptedData *target);
564 * Decrypt a given block with the hostkey.
566 * @param key the key to use
567 * @param block the data to decrypt, encoded as returned by encrypt, not consumed
568 * @param result pointer to a location where the result can be stored
569 * @param size how many bytes of a result are expected? Must be exact.
570 * @returns the size of the decrypted block (that is, size) or -1 on error
572 ssize_t GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
573 const struct GNUNET_CRYPTO_RsaEncryptedData
580 * Sign a given block.
582 * @param key private key to use for the signing
583 * @param purpose what to sign (size, purpose)
584 * @param result where to write the signature
585 * @return GNUNET_SYSERR on error, GNUNET_OK on success
587 int GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key,
588 const struct GNUNET_CRYPTO_RsaSignaturePurpose
590 struct GNUNET_CRYPTO_RsaSignature *result);
594 * Verify signature. Note that the caller MUST have already
595 * checked that "validate->size" bytes are actually available.
597 * @param purpose what is the purpose that validate should have?
598 * @param validate block to validate (size, purpose, data)
599 * @param sig signature that is being validated
600 * @param publicKey public key of the signer
601 * @returns GNUNET_OK if ok, GNUNET_SYSERR if invalid
603 int GNUNET_CRYPTO_rsa_verify (uint32_t purpose,
604 const struct GNUNET_CRYPTO_RsaSignaturePurpose
606 const struct GNUNET_CRYPTO_RsaSignature *sig,
608 GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded
614 * This function should only be called in testcases
615 * where strong entropy gathering is not desired
616 * (for example, for hostkey generation).
618 void GNUNET_CRYPTO_random_disable_entropy_gathering (void);
620 #if 0 /* keep Emacsens' auto-indent happy */
628 /* ifndef GNUNET_CRYPTO_LIB_H */
630 /* end of gnunet_crypto_lib.h */