Implement automatic reseeding of DRBG after a specified time interval
[openssl.git] / include / internal / rand.h
1 /*
2  * Copyright 2017 The OpenSSL Project Authors. All Rights Reserved.
3  *
4  * Licensed under the OpenSSL license (the "License").  You may not use
5  * this file except in compliance with the License.  You can obtain a copy
6  * in the file LICENSE in the source distribution or at
7  * https://www.openssl.org/source/license.html
8  */
9
10 #ifndef HEADER_DRBG_RAND_H
11 # define HEADER_DRBG_RAND_H
12
13 /* In CTR mode, use derivation function ctr_df */
14 #define RAND_DRBG_FLAG_CTR_USE_DF            0x2
15
16 /*
17  * Default security strength (in the sense of [NIST SP 800-90Ar1])
18  * of the default OpenSSL DRBG, and the corresponding NID.
19  *
20  * Currently supported values: 128, 192, 256
21  *
22  * TODO(DRBG): would be nice to have the strength configurable
23  */
24 # define RAND_DRBG_STRENGTH             128
25 # define RAND_DRBG_NID                  NID_aes_128_ctr
26
27 /*
28  * Object lifetime functions.
29  */
30 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent);
31 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags);
32 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
33                           const unsigned char *pers, size_t perslen);
34 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg);
35 void RAND_DRBG_free(RAND_DRBG *drbg);
36
37 /*
38  * Object "use" functions.
39  */
40 int RAND_DRBG_reseed(RAND_DRBG *drbg,
41                      const unsigned char *adin, size_t adinlen);
42 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
43                        int prediction_resistance,
44                        const unsigned char *adin, size_t adinlen);
45 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval);
46 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval);
47
48 RAND_DRBG *RAND_DRBG_get0_master(void);
49 RAND_DRBG *RAND_DRBG_get0_public(void);
50 RAND_DRBG *RAND_DRBG_get0_private(void);
51
52 /*
53  * EXDATA
54  */
55 #define RAND_DRBG_get_ex_new_index(l, p, newf, dupf, freef) \
56     CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_DRBG, l, p, newf, dupf, freef)
57 int RAND_DRBG_set_ex_data(RAND_DRBG *dctx, int idx, void *arg);
58 void *RAND_DRBG_get_ex_data(const RAND_DRBG *dctx, int idx);
59
60 /*
61  * Callback functions.  See comments in drbg_lib.c
62  */
63 typedef size_t (*RAND_DRBG_get_entropy_fn)(RAND_DRBG *ctx,
64                                            unsigned char **pout,
65                                            int entropy, size_t min_len,
66                                            size_t max_len);
67 typedef void (*RAND_DRBG_cleanup_entropy_fn)(RAND_DRBG *ctx,
68                                              unsigned char *out, size_t outlen);
69 typedef size_t (*RAND_DRBG_get_nonce_fn)(RAND_DRBG *ctx, unsigned char **pout,
70                                          int entropy, size_t min_len,
71                                          size_t max_len);
72 typedef void (*RAND_DRBG_cleanup_nonce_fn)(RAND_DRBG *ctx,
73                                            unsigned char *out, size_t outlen);
74
75 int RAND_DRBG_set_callbacks(RAND_DRBG *dctx,
76                             RAND_DRBG_get_entropy_fn get_entropy,
77                             RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
78                             RAND_DRBG_get_nonce_fn get_nonce,
79                             RAND_DRBG_cleanup_nonce_fn cleanup_nonce);
80
81 /*
82  * RAND_POOL functions
83  */
84 RAND_POOL *RAND_POOL_new(int entropy_requested, size_t min_len, size_t max_len);
85 void RAND_POOL_free(RAND_POOL *pool);
86
87 const unsigned char *RAND_POOL_buffer(RAND_POOL *pool);
88 unsigned char *RAND_POOL_detach(RAND_POOL *pool);
89
90 size_t RAND_POOL_entropy(RAND_POOL *pool);
91 size_t RAND_POOL_length(RAND_POOL *pool);
92
93 size_t RAND_POOL_entropy_available(RAND_POOL *pool);
94 size_t RAND_POOL_entropy_needed(RAND_POOL *pool);
95 size_t RAND_POOL_bytes_needed(RAND_POOL *pool, unsigned int entropy_per_byte);
96 size_t RAND_POOL_bytes_remaining(RAND_POOL *pool);
97
98 size_t RAND_POOL_add(RAND_POOL *pool,
99                      const unsigned char *buffer, size_t len, size_t entropy);
100 unsigned char *RAND_POOL_add_begin(RAND_POOL *pool, size_t len);
101 size_t RAND_POOL_add_end(RAND_POOL *pool, size_t len, size_t entropy);
102
103
104 /*
105  * Add random bytes to the pool to acquire requested amount of entropy
106  *
107  * This function is platform specific and tries to acquire the requested
108  * amount of entropy by polling platform specific entropy sources.
109  *
110  * If the function succeeds in acquiring at least |entropy_requested| bits
111  * of entropy, the total entropy count is returned. If it fails, it returns
112  * an entropy count of 0.
113  */
114 size_t RAND_POOL_acquire_entropy(RAND_POOL *pool);
115 #endif