/* This file is part of GNUnet. (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007 Christian Grothoff (and other contributing authors) GNUnet is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GNUnet; see the file COPYING. If not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ /** * @file include/gnunet_crypto_lib.h * @brief cryptographic primitives for GNUnet * * @author Christian Grothoff * @author Krista Bennett * @author Gerd Knorr * @author Ioana Patrascu * @author Tzvetan Horozov */ #ifndef GNUNET_CRYPTO_LIB_H #define GNUNET_CRYPTO_LIB_H #ifdef __cplusplus extern "C" { #if 0 /* keep Emacsens' auto-indent happy */ } #endif #endif #include "gnunet_common.h" #include "gnunet_scheduler_lib.h" /** * Desired quality level for cryptographic operations. */ enum GNUNET_CRYPTO_Quality { /** * No good quality of the operation is needed (i.e., * random numbers can be pseudo-random). */ GNUNET_CRYPTO_QUALITY_WEAK, /** * High-quality operations are desired. */ GNUNET_CRYPTO_QUALITY_STRONG, /** * Randomness for IVs etc. is required. */ GNUNET_CRYPTO_QUALITY_NONCE }; /** * @brief length of the sessionkey in bytes (256 BIT sessionkey) */ #define GNUNET_CRYPTO_AES_KEY_LENGTH (256/8) /** * @brief Length of RSA encrypted data (2048 bit) * * We currently do not handle encryption of data * that can not be done in a single call to the * RSA methods (read: large chunks of data). * We should never need that, as we can use * the GNUNET_CRYPTO_hash for larger pieces of data for signing, * and for encryption, we only need to encode sessionkeys! */ #define GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH 256 /** * Length of an RSA KEY (d,e,len), 2048 bit (=256 octests) key d, 2 byte e */ #define GNUNET_CRYPTO_RSA_KEY_LENGTH 258 /** * Length of a hash value */ #define GNUNET_CRYPTO_HASH_LENGTH 512/8 /** * The private information of an RSA key pair. */ struct GNUNET_CRYPTO_RsaPrivateKey; /** * @brief 0-terminated ASCII encoding of a GNUNET_HashCode. */ struct GNUNET_CRYPTO_HashAsciiEncoded { unsigned char encoding[104]; }; /** * @brief an RSA signature */ struct GNUNET_CRYPTO_RsaSignature { unsigned char sig[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH]; }; /** * @brief header of what an RSA signature signs * this must be followed by "size - 8" bytes of * the actual signed data */ struct GNUNET_CRYPTO_RsaSignaturePurpose { /** * How many bytes does this signature sign? * (including this purpose header); in network * byte order (!). */ uint32_t size GNUNET_PACKED; /** * What does this signature vouch for? This * must contain a GNUNET_SIGNATURE_PURPOSE_XXX * constant (from gnunet_signatures.h). In * network byte order! */ uint32_t purpose GNUNET_PACKED; }; /** * @brief A public key. */ struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded { /** * In big-endian, must be GNUNET_CRYPTO_RSA_KEY_LENGTH+4 */ uint16_t len GNUNET_PACKED; /** * Size of n in key; in big-endian! */ uint16_t sizen GNUNET_PACKED; /** * The key itself, contains n followed by e. */ unsigned char key[GNUNET_CRYPTO_RSA_KEY_LENGTH]; /** * Padding (must be 0) */ uint16_t padding GNUNET_PACKED; }; /** * RSA Encrypted data. */ struct GNUNET_CRYPTO_RsaEncryptedData { unsigned char encoding[GNUNET_CRYPTO_RSA_DATA_ENCODING_LENGTH]; }; /** * @brief type for session keys */ struct GNUNET_CRYPTO_AesSessionKey { /** * Actual key. */ unsigned char key[GNUNET_CRYPTO_AES_KEY_LENGTH]; /** * checksum! */ uint32_t crc32 GNUNET_PACKED; }; /** * @brief IV for sym cipher * * NOTE: must be smaller (!) in size than the * GNUNET_HashCode. */ struct GNUNET_CRYPTO_AesInitializationVector { unsigned char iv[GNUNET_CRYPTO_AES_KEY_LENGTH / 2]; }; /** * @brief type for (message) authentication keys */ struct GNUNET_CRYPTO_AuthKey { unsigned char key[GNUNET_CRYPTO_HASH_LENGTH]; }; /* **************** Functions and Macros ************* */ /** * Compute the CRC32 checksum for the first len * bytes of the buffer. * * @param buf the data over which we're taking the CRC * @param len the length of the buffer in bytes * @return the resulting CRC32 checksum */ int32_t GNUNET_CRYPTO_crc32_n (const void *buf, size_t len); /** * Produce a random value. * * @param mode desired quality of the random number * @param i the upper limit (exclusive) for the random number * @return a random value in the interval [0,i) (exclusive). */ uint32_t GNUNET_CRYPTO_random_u32 (enum GNUNET_CRYPTO_Quality mode, uint32_t i); /** * Random on unsigned 64-bit values. * * @param mode desired quality of the random number * @param max value returned will be in range [0,max) (exclusive) * @return random 64-bit number */ uint64_t GNUNET_CRYPTO_random_u64 (enum GNUNET_CRYPTO_Quality mode, uint64_t max); /** * Get an array with a random permutation of the * numbers 0...n-1. * @param mode GNUNET_CRYPTO_QUALITY_STRONG if the strong (but expensive) PRNG should be used, GNUNET_CRYPTO_QUALITY_WEAK otherwise * @param n the size of the array * @return the permutation array (allocated from heap) */ unsigned int * GNUNET_CRYPTO_random_permute (enum GNUNET_CRYPTO_Quality mode, unsigned int n); /** * Create a new Session key. * * @param key key to initialize */ void GNUNET_CRYPTO_aes_create_session_key (struct GNUNET_CRYPTO_AesSessionKey *key); /** * Check that a new session key is well-formed. * * @param key key to check * @return GNUNET_OK if the key is valid */ int GNUNET_CRYPTO_aes_check_session_key (const struct GNUNET_CRYPTO_AesSessionKey *key); /** * Encrypt a block with the public key of another * host that uses the same cyper. * * @param block the block to encrypt * @param len the size of the block * @param sessionkey the key used to encrypt * @param iv the initialization vector to use, use INITVALUE * for streams. * @return the size of the encrypted block, -1 for errors */ ssize_t GNUNET_CRYPTO_aes_encrypt (const void *block, size_t len, const struct GNUNET_CRYPTO_AesSessionKey *sessionkey, const struct GNUNET_CRYPTO_AesInitializationVector *iv, void *result); /** * Decrypt a given block with the sessionkey. * * @param block the data to decrypt, encoded as returned by encrypt * @param size how big is the block? * @param sessionkey the key used to decrypt * @param iv the initialization vector to use * @param result address to store the result at * @return -1 on failure, size of decrypted block on success */ ssize_t GNUNET_CRYPTO_aes_decrypt (const void *block, size_t size, const struct GNUNET_CRYPTO_AesSessionKey *sessionkey, const struct GNUNET_CRYPTO_AesInitializationVector *iv, void *result); /** * @brief Derive an IV * @param iv initialization vector * @param skey session key * @param salt salt for the derivation * @param salt_len size of the salt * @param ... pairs of void * & size_t for context chunks, terminated by NULL */ void GNUNET_CRYPTO_aes_derive_iv (struct GNUNET_CRYPTO_AesInitializationVector *iv, const struct GNUNET_CRYPTO_AesSessionKey *skey, const void *salt, size_t salt_len, ...); /** * @brief Derive an IV * @param iv initialization vector * @param skey session key * @param salt salt for the derivation * @param salt_len size of the salt * @param argp pairs of void * & size_t for context chunks, terminated by NULL */ void GNUNET_CRYPTO_aes_derive_iv_v (struct GNUNET_CRYPTO_AesInitializationVector *iv, const struct GNUNET_CRYPTO_AesSessionKey *skey, const void *salt, size_t salt_len, va_list argp); /** * Convert hash to ASCII encoding. * @param block the hash code * @param result where to store the encoding (struct GNUNET_CRYPTO_HashAsciiEncoded can be * safely cast to char*, a '\\0' termination is set). */ void GNUNET_CRYPTO_hash_to_enc (const GNUNET_HashCode * block, struct GNUNET_CRYPTO_HashAsciiEncoded *result); /** * Convert ASCII encoding back to GNUNET_CRYPTO_hash * @param enc the encoding * @param result where to store the GNUNET_CRYPTO_hash code * @return GNUNET_OK on success, GNUNET_SYSERR if result has the wrong encoding */ int GNUNET_CRYPTO_hash_from_string (const char *enc, GNUNET_HashCode * result); /** * Compute the distance between 2 hashcodes. * The computation must be fast, not involve * a.a or a.e (they're used elsewhere), and * be somewhat consistent. And of course, the * result should be a positive number. * * @param a some hash code * @param b some hash code * @return number between 0 and UINT32_MAX */ uint32_t GNUNET_CRYPTO_hash_distance_u32 (const GNUNET_HashCode * a, const GNUNET_HashCode * b); /** * Compute hash of a given block. * * @param block the data to hash * @param size size of the block * @param ret pointer to where to write the hashcode */ void GNUNET_CRYPTO_hash (const void *block, size_t size, GNUNET_HashCode * ret); /** * Calculate HMAC of a message (RFC 2104) * * @param key secret key * @param plaintext input plaintext * @param plaintext_len length of plaintext * @param hmac where to store the hmac */ void GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key, const void *plaintext, size_t plaintext_len, GNUNET_HashCode * hmac); /** * Function called once the hash computation over the * specified file has completed. * * @param cls closure * @param res resulting hash, NULL on error */ typedef void (*GNUNET_CRYPTO_HashCompletedCallback) (void *cls, const GNUNET_HashCode * res); /** * Handle to file hashing operation. */ struct GNUNET_CRYPTO_FileHashContext; /** * Compute the hash of an entire file. * * @param priority scheduling priority to use * @param filename name of file to hash * @param blocksize number of bytes to process in one task * @param callback function to call upon completion * @param callback_cls closure for callback * @return NULL on (immediate) errror */ struct GNUNET_CRYPTO_FileHashContext * GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority, const char *filename, size_t blocksize, GNUNET_CRYPTO_HashCompletedCallback callback, void *callback_cls); /** * Cancel a file hashing operation. * * @param fhc operation to cancel (callback must not yet have been invoked) */ void GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc); /** * Create a random hash code. * * @param mode desired quality level * @param result hash code that is randomized */ void GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode, GNUNET_HashCode * result); /** * compute result(delta) = b - a * * @param a some hash code * @param b some hash code * @param result set to b - a */ void GNUNET_CRYPTO_hash_difference (const GNUNET_HashCode * a, const GNUNET_HashCode * b, GNUNET_HashCode * result); /** * compute result(b) = a + delta * * @param a some hash code * @param delta some hash code * @param result set to a + delta */ void GNUNET_CRYPTO_hash_sum (const GNUNET_HashCode * a, const GNUNET_HashCode * delta, GNUNET_HashCode * result); /** * compute result = a ^ b * * @param a some hash code * @param b some hash code * @param result set to a ^ b */ void GNUNET_CRYPTO_hash_xor (const GNUNET_HashCode * a, const GNUNET_HashCode * b, GNUNET_HashCode * result); /** * Convert a hashcode into a key. * * @param hc hash code that serves to generate the key * @param skey set to a valid session key * @param iv set to a valid initialization vector */ void GNUNET_CRYPTO_hash_to_aes_key (const GNUNET_HashCode * hc, struct GNUNET_CRYPTO_AesSessionKey *skey, struct GNUNET_CRYPTO_AesInitializationVector *iv); /** * Obtain a bit from a hashcode. * * @param code the GNUNET_CRYPTO_hash to index bit-wise * @param bit index into the hashcode, [0...159] * @return Bit \a bit from hashcode \a code, -1 for invalid index */ int GNUNET_CRYPTO_hash_get_bit (const GNUNET_HashCode * code, unsigned int bit); /** * Determine how many low order bits match in two * GNUNET_HashCodes. i.e. - 010011 and 011111 share * the first two lowest order bits, and therefore the * return value is two (NOT XOR distance, nor how many * bits match absolutely!). * * @param first the first hashcode * @param second the hashcode to compare first to * * @return the number of bits that match */ unsigned int GNUNET_CRYPTO_hash_matching_bits (const GNUNET_HashCode * first, const GNUNET_HashCode * second); /** * Compare function for HashCodes, producing a total ordering * of all hashcodes. * * @param h1 some hash code * @param h2 some hash code * @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2. */ int GNUNET_CRYPTO_hash_cmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2); /** * Find out which of the two GNUNET_CRYPTO_hash codes is closer to target * in the XOR metric (Kademlia). * * @param h1 some hash code * @param h2 some hash code * @param target some hash code * @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2. */ int GNUNET_CRYPTO_hash_xorcmp (const GNUNET_HashCode * h1, const GNUNET_HashCode * h2, const GNUNET_HashCode * target); /** * @brief Derive an authentication key * @param key authentication key * @param rkey root key * @param salt salt * @param salt_len size of the salt * @param argp pair of void * & size_t for context chunks, terminated by NULL */ void GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key, const struct GNUNET_CRYPTO_AesSessionKey *rkey, const void *salt, size_t salt_len, va_list argp); /** * @brief Derive an authentication key * @param key authentication key * @param rkey root key * @param salt salt * @param salt_len size of the salt * @param ... pair of void * & size_t for context chunks, terminated by NULL */ void GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key, const struct GNUNET_CRYPTO_AesSessionKey *rkey, const void *salt, size_t salt_len, ...); /** * @brief Derive key * @param result buffer for the derived key, allocated by caller * @param out_len desired length of the derived key * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_... * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_... * @param xts salt * @param xts_len length of xts * @param skm source key material * @param skm_len length of skm * @return GNUNET_YES on success */ int GNUNET_CRYPTO_hkdf (void *result, size_t out_len, int xtr_algo, int prf_algo, const void *xts, size_t xts_len, const void *skm, size_t skm_len, ...); /** * @brief Derive key * @param result buffer for the derived key, allocated by caller * @param out_len desired length of the derived key * @param xtr_algo hash algorithm for the extraction phase, GCRY_MD_... * @param prf_algo hash algorithm for the expansion phase, GCRY_MD_... * @param xts salt * @param xts_len length of xts * @param skm source key material * @param skm_len length of skm * @param argp va_list of void * & size_t pairs for context chunks * @return GNUNET_YES on success */ int GNUNET_CRYPTO_hkdf_v (void *result, size_t out_len, int xtr_algo, int prf_algo, const void *xts, size_t xts_len, const void *skm, size_t skm_len, va_list argp); /** * @brief Derive key * @param result buffer for the derived key, allocated by caller * @param out_len desired length of the derived key * @param xts salt * @param xts_len length of xts * @param skm source key material * @param skm_len length of skm * @param argp va_list of void * & size_t pairs for context chunks * @return GNUNET_YES on success */ int GNUNET_CRYPTO_kdf_v (void *result, size_t out_len, const void *xts, size_t xts_len, const void *skm, size_t skm_len, va_list argp); /** * @brief Derive key * @param result buffer for the derived key, allocated by caller * @param out_len desired length of the derived key * @param xts salt * @param xts_len length of xts * @param skm source key material * @param skm_len length of skm * @param ... void * & size_t pairs for context chunks * @return GNUNET_YES on success */ int GNUNET_CRYPTO_kdf (void *result, size_t out_len, const void *xts, size_t xts_len, const void *skm, size_t skm_len, ...); /** * Create a new private key. Caller must free return value. * * @return fresh private key */ struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_key_create (void); /** * Decode the private key from the data-format back * to the "normal", internal format. * * @param buf the buffer where the private key data is stored * @param len the length of the data in 'buffer' */ struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_decode_key (const char *buf, uint16_t len); /** * Create a new private key by reading it from a file. If the * files does not exist, create a new key and write it to the * file. Caller must free return value. Note that this function * can not guarantee that another process might not be trying * the same operation on the same file at the same time. * If the contents of the file * are invalid the old file is deleted and a fresh key is * created. * * @param filename name of file to use for storage * @return new private key, NULL on error (for example, * permission denied) */ struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_key_create_from_file (const char *filename); /** * Deterministically (!) create a private key using only the * given HashCode as input to the PRNG. * * @param hc "random" input to PRNG * @return some private key purely dependent on input */ struct GNUNET_CRYPTO_RsaPrivateKey * GNUNET_CRYPTO_rsa_key_create_from_hash (const GNUNET_HashCode * hc); /** * Free memory occupied by the private key. * @param hostkey pointer to the memory to free */ void GNUNET_CRYPTO_rsa_key_free (struct GNUNET_CRYPTO_RsaPrivateKey *hostkey); /** * Extract the public key of the host. * * @param priv the private key * @param pub where to write the public key */ void GNUNET_CRYPTO_rsa_key_get_public (const struct GNUNET_CRYPTO_RsaPrivateKey *priv, struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *pub); /** * Encrypt a block with the public key of another host that uses the * same cyper. * * @param block the block to encrypt * @param size the size of block * @param publicKey the encoded public key used to encrypt * @param target where to store the encrypted block * @return GNUNET_SYSERR on error, GNUNET_OK if ok */ int GNUNET_CRYPTO_rsa_encrypt (const void *block, size_t size, const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *publicKey, struct GNUNET_CRYPTO_RsaEncryptedData *target); /** * Decrypt a given block with the hostkey. * * @param key the key to use * @param block the data to decrypt, encoded as returned by encrypt, not consumed * @param result pointer to a location where the result can be stored * @param max how many bytes of a result are expected? Must be exact. * @return the size of the decrypted block (that is, size) or -1 on error */ ssize_t GNUNET_CRYPTO_rsa_decrypt (const struct GNUNET_CRYPTO_RsaPrivateKey *key, const struct GNUNET_CRYPTO_RsaEncryptedData *block, void *result, size_t max); /** * Sign a given block. * * @param key private key to use for the signing * @param purpose what to sign (size, purpose) * @param sig where to write the signature * @return GNUNET_SYSERR on error, GNUNET_OK on success */ int GNUNET_CRYPTO_rsa_sign (const struct GNUNET_CRYPTO_RsaPrivateKey *key, const struct GNUNET_CRYPTO_RsaSignaturePurpose *purpose, struct GNUNET_CRYPTO_RsaSignature *sig); /** * Verify signature. Note that the caller MUST have already * checked that "validate->size" bytes are actually available. * * @param purpose what is the purpose that validate should have? * @param validate block to validate (size, purpose, data) * @param sig signature that is being validated * @param publicKey public key of the signer * @return GNUNET_OK if ok, GNUNET_SYSERR if invalid */ int GNUNET_CRYPTO_rsa_verify (uint32_t purpose, const struct GNUNET_CRYPTO_RsaSignaturePurpose *validate, const struct GNUNET_CRYPTO_RsaSignature *sig, const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *publicKey); /** * This function should only be called in testcases * where strong entropy gathering is not desired * (for example, for hostkey generation). */ void GNUNET_CRYPTO_random_disable_entropy_gathering (void); #if 0 /* keep Emacsens' auto-indent happy */ { #endif #ifdef __cplusplus } #endif /* ifndef GNUNET_CRYPTO_LIB_H */ #endif /* end of gnunet_crypto_lib.h */