2 * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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
10 #ifndef HEADER_RAND_LCL_H
11 # define HEADER_RAND_LCL_H
13 # include <openssl/aes.h>
14 # include <openssl/evp.h>
15 # include <openssl/sha.h>
16 # include <openssl/hmac.h>
17 # include <openssl/ec.h>
18 # include "internal/rand.h"
20 /* How many times to read the TSC as a randomness source. */
21 # define TSC_READ_COUNT 4
23 /* Maximum count allowed in reseeding */
24 # define MAX_RESEED (1 << 24)
26 /* Max size of additional input and personalization string. */
27 # define DRBG_MAX_LENGTH 4096
30 * The quotient between max_{entropy,nonce}len and min_{entropy,nonce}len
32 * The current factor is large enough that the RAND_POOL can store a
33 * random input which has a lousy entropy rate of 0.0625 bits per byte.
34 * This input will be sent through the derivation function which 'compresses'
35 * the low quality input into a high quality output.
37 # define DRBG_MINMAX_FACTOR 128
40 /* DRBG status values */
41 typedef enum drbg_status_e {
50 * The state of a DRBG AES-CTR.
52 typedef struct rand_drbg_ctr_st {
57 /* Temp variables used by derivation function */
60 /* Temporary block storage used by ctr_df */
61 unsigned char bltmp[16];
68 * The state of all types of DRBGs, even though we only have CTR mode
74 int nid; /* the underlying algorithm */
76 unsigned short flags; /* various external flags */
79 * The random pool is used by RAND_add()/drbg_add() to attach random
80 * data to the global drbg, such that the rand_drbg_get_entropy() callback
81 * can pull it during instantiation and reseeding. This is necessary to
82 * reconcile the different philosophies of the RAND and the RAND_DRBG
83 * with respect to how randomness is added to the RNG during reseeding
89 * The following parameters are setup by the per-type "init" function.
91 * Currently the only type is CTR_DRBG, its init function is ctr_init().
93 * The parameters are closely related to the ones described in
94 * section '10.2.1 CTR_DRBG' of [NIST SP 800-90Ar1], with one
95 * crucial difference: In the NIST standard, all counts are given
96 * in bits, whereas in OpenSSL entropy counts are given in bits
97 * and buffer lengths are given in bytes.
99 * Since this difference has lead to some confusion in the past,
100 * (see [GitHub Issue #2443], formerly [rt.openssl.org #4055])
101 * the 'len' suffix has been added to all buffer sizes for
107 size_t min_entropylen, max_entropylen;
108 size_t min_noncelen, max_noncelen;
109 size_t max_perslen, max_adinlen;
110 unsigned int reseed_counter;
111 unsigned int reseed_interval;
115 /* Application data, mainly used in the KATs. */
116 CRYPTO_EX_DATA ex_data;
118 /* Implementation specific structures; was a union, but inline for now */
121 /* Callback functions. See comments in rand_lib.c */
122 RAND_DRBG_get_entropy_fn get_entropy;
123 RAND_DRBG_cleanup_entropy_fn cleanup_entropy;
124 RAND_DRBG_get_nonce_fn get_nonce;
125 RAND_DRBG_cleanup_nonce_fn cleanup_nonce;
128 /* The global RAND method, and the global buffer and DRBG instance. */
129 extern RAND_METHOD rand_meth;
131 /* How often we've forked (only incremented in child). */
132 extern int rand_fork_count;
134 /* Hardware-based seeding functions. */
135 size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool);
136 size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool);
138 /* DRBG entropy callbacks. */
139 size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
140 unsigned char **pout,
141 int entropy, size_t min_len, size_t max_len);
142 void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
143 unsigned char *out, size_t outlen);
146 int rand_drbg_restart(RAND_DRBG *drbg,
147 const unsigned char *buffer, size_t len, size_t entropy);
149 /* DRBG functions implementing AES-CTR */
150 int ctr_init(RAND_DRBG *drbg);
151 int ctr_uninstantiate(RAND_DRBG *drbg);
152 int ctr_instantiate(RAND_DRBG *drbg,
153 const unsigned char *entropy, size_t entropylen,
154 const unsigned char *nonce, size_t noncelen,
155 const unsigned char *pers, size_t perslen);
156 int ctr_reseed(RAND_DRBG *drbg,
157 const unsigned char *entropy, size_t entropylen,
158 const unsigned char *adin, size_t adinlen);
159 int ctr_generate(RAND_DRBG *drbg,
160 unsigned char *out, size_t outlen,
161 const unsigned char *adin, size_t adinlen);