1 /* Copyright (c) (2010,2011,2012,2013,2014,2015,2016,2017,2018,2019) Apple Inc. All rights reserved. 2 * 3 * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which 4 * is contained in the License.txt file distributed with corecrypto) and only to 5 * people who accept that license. IMPORTANT: Any license rights granted to you by 6 * Apple Inc. (if any) are limited to internal use within your organization only on 7 * devices and computers you own or control, for the sole purpose of verifying the 8 * security characteristics and correct functioning of the Apple Software. You may 9 * not, directly or indirectly, redistribute the Apple Software or any portions thereof. 10 */ 11 12 #ifndef _CORECRYPTO_CCRNG_H_ 13 #define _CORECRYPTO_CCRNG_H_ 14 15 #include <corecrypto/cc.h> 16 17 #define CCRNG_STATE_COMMON \ 18 int (*CC_SPTR(ccrng_state, generate))(struct ccrng_state *rng, size_t outlen, void *out); 19 20 /*! 21 @type struct ccrng_state 22 @abstract Default state structure. Do not instantiate. ccrng() returns a reference to this structure 23 */ 24 struct ccrng_state { 25 CCRNG_STATE_COMMON 26 }; 27 28 /*! 29 @function ccrng 30 @abstract Initializes an AES-CTR mode cryptographic random number generator and returns the statically-allocated rng object. 31 Getting a pointer to a ccrng has never been simpler! 32 Call this function, get an rng object and then pass the object to ccrng_generate() to generate randoms. 33 ccrng() may be called more than once. It returns pointer to the same object on all calls. 34 35 @result a cryptographically secure random number generator or NULL if fails 36 37 @discussion 38 - It is significantly faster than using the system /dev/random 39 - FIPS Compliant: NIST SP800-90A + FIPS 140-2 40 - Seeded from the system entropy. 41 - Provides at least 128bit security if the system provide 2bit of entropy / byte. 42 - Entropy accumulation 43 - Backtracing resistance 44 - Prediction break with frequent (asynchronous) reseed 45 */ 46 47 struct ccrng_state *ccrng(int *error); 48 49 /*! 50 @function ccrng_generate 51 @abstract Generate `outlen` bytes of output, stored in `out`, using ccrng_state `rng`. 52 53 @param rng `struct ccrng_state` representing the state of the RNG. 54 @param outlen Amount of random bytes to generate. 55 @param out Pointer to memory where random bytes are stored, of size at least `outlen`. 56 57 @result 0 on success and nonzero on failure. 58 */ 59 #define ccrng_generate(rng, outlen, out) \ 60 ((rng)->generate((struct ccrng_state *)(rng), (outlen), (out))) 61 62 /*! 63 @function ccrng_uniform 64 @abstract Generate a random value in @p [0, bound). 65 66 @param rng The state of the RNG. 67 @param bound The exclusive upper bound on the output. 68 @param rand A pointer to a single @p uint64_t to store the result. 69 70 @result Returns zero iff the operation is successful. 71 */ 72 int ccrng_uniform(struct ccrng_state *rng, uint64_t bound, uint64_t *rand); 73 74 #endif /* _CORECRYPTO_CCRNG_H_ */ 75