1EVP_RAND-HMAC-DRBG(7ossl)           OpenSSL          EVP_RAND-HMAC-DRBG(7ossl)
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NAME

6       EVP_RAND-HMAC-DRBG - The HMAC DRBG EVP_RAND implementation
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DESCRIPTION

9       Support for the HMAC deterministic random bit generator through the
10       EVP_RAND API.
11
12   Identity
13       "HMAC-DRBG" is the name for this implementation; it can be used with
14       the EVP_RAND_fetch() function.
15
16   Supported parameters
17       The supported parameters are:
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19       "state" (OSSL_RAND_PARAM_STATE) <integer>
20       "strength" (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>
21       "max_request" (OSSL_RAND_PARAM_MAX_REQUEST) <unsigned integer>
22       "reseed_requests" (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
23       "reseed_time_interval" (OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL) <integer>
24       "min_entropylen" (OSSL_DRBG_PARAM_MIN_ENTROPYLEN) <unsigned integer>
25       "max_entropylen" (OSSL_DRBG_PARAM_MAX_ENTROPYLEN) <unsigned integer>
26       "min_noncelen" (OSSL_DRBG_PARAM_MIN_NONCELEN) <unsigned integer>
27       "max_noncelen" (OSSL_DRBG_PARAM_MAX_NONCELEN) <unsigned integer>
28       "max_perslen" (OSSL_DRBG_PARAM_MAX_PERSLEN) <unsigned integer>
29       "max_adinlen" (OSSL_DRBG_PARAM_MAX_ADINLEN) <unsigned integer>
30       "reseed_counter" (OSSL_DRBG_PARAM_RESEED_COUNTER) <unsigned integer>
31       "properties" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>
32       "mac" (OSSL_DRBG_PARAM_MAC) <UTF8 string>
33       "digest" (OSSL_DRBG_PARAM_DIGEST) <UTF8 string>
34           These parameters work as described in "PARAMETERS" in EVP_RAND(3).
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NOTES

37       When using the FIPS provider, only these digests are permitted (as per
38       FIPS 140-3 IG D.R
39       <https://csrc.nist.gov/CSRC/media/Projects/cryptographic-module-
40       validation-program/documents/fips%20140-3/FIPS%20140-3%20IG.pdf>):
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42       SHA-1
43       SHA2-256
44       SHA2-512
45       SHA3-256
46       SHA3-512
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48       A context for HMAC DRBG can be obtained by calling:
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50        EVP_RAND *rand = EVP_RAND_fetch(NULL, "HMAC-DRBG", NULL);
51        EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand);
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EXAMPLES

54        EVP_RAND *rand;
55        EVP_RAND_CTX *rctx;
56        unsigned char bytes[100];
57        OSSL_PARAM params[3], *p = params;
58        unsigned int strength = 128;
59
60        rand = EVP_RAND_fetch(NULL, "HMAC-DRBG", NULL);
61        rctx = EVP_RAND_CTX_new(rand, NULL);
62        EVP_RAND_free(rand);
63
64        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_MAC, SN_hmac, 0);
65        *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST, SN_sha256, 0);
66        *p = OSSL_PARAM_construct_end();
67        EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params);
68
69        EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0);
70
71        EVP_RAND_CTX_free(rctx);
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CONFORMING TO

74       NIST SP 800-90A and SP 800-90B
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SEE ALSO

77       EVP_RAND(3), "PARAMETERS" in EVP_RAND(3), openssl-fipsinstall(1)
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HISTORY

80       OpenSSL 3.1.1 introduced the -no_drbg_truncated_digests option to
81       fipsinstall which restricts the permitted digests when using the FIPS
82       provider in a complaint manner.  For details refer to FIPS 140-3 IG D.R
83       <https://csrc.nist.gov/CSRC/media/Projects/cryptographic-module-
84       validation-program/documents/fips%20140-3/FIPS%20140-3%20IG.pdf>).
85

87       Copyright 2020-2023 The OpenSSL Project Authors. All Rights Reserved.
88
89       Licensed under the Apache License 2.0 (the "License").  You may not use
90       this file except in compliance with the License.  You can obtain a copy
91       in the file LICENSE in the source distribution or at
92       <https://www.openssl.org/source/license.html>.
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963.1.1                             2023-08-31         EVP_RAND-HMAC-DRBG(7ossl)
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