1=pod 2 3=head1 NAME 4 5EVP_RAND-HASH-DRBG - The HASH DRBG EVP_RAND implementation 6 7=head1 DESCRIPTION 8 9Support for the hash deterministic random bit generator through the 10B<EVP_RAND> API. 11 12=head2 Identity 13 14"HASH-DRBG" is the name for this implementation; it can be used with the 15EVP_RAND_fetch() function. 16 17=head2 Supported parameters 18 19The supported parameters are: 20 21=over 4 22 23=item "state" (B<OSSL_RAND_PARAM_STATE>) <integer> 24 25=item "strength" (B<OSSL_RAND_PARAM_STRENGTH>) <unsigned integer> 26 27=item "max_request" (B<OSSL_RAND_PARAM_MAX_REQUEST>) <unsigned integer> 28 29=item "reseed_requests" (B<OSSL_DRBG_PARAM_RESEED_REQUESTS>) <unsigned integer> 30 31=item "reseed_time_interval" (B<OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL>) <integer> 32 33=item "min_entropylen" (B<OSSL_DRBG_PARAM_MIN_ENTROPYLEN>) <unsigned integer> 34 35=item "max_entropylen" (B<OSSL_DRBG_PARAM_MAX_ENTROPYLEN>) <unsigned integer> 36 37=item "min_noncelen" (B<OSSL_DRBG_PARAM_MIN_NONCELEN>) <unsigned integer> 38 39=item "max_noncelen" (B<OSSL_DRBG_PARAM_MAX_NONCELEN>) <unsigned integer> 40 41=item "max_perslen" (B<OSSL_DRBG_PARAM_MAX_PERSLEN>) <unsigned integer> 42 43=item "max_adinlen" (B<OSSL_DRBG_PARAM_MAX_ADINLEN>) <unsigned integer> 44 45=item "reseed_counter" (B<OSSL_DRBG_PARAM_RESEED_COUNTER>) <unsigned integer> 46 47=item "properties" (B<OSSL_DRBG_PARAM_PROPERTIES>) <UTF8 string> 48 49=item "digest" (B<OSSL_DRBG_PARAM_DIGEST>) <UTF8 string> 50 51These parameters work as described in L<EVP_RAND(3)/PARAMETERS>. 52 53=back 54 55=head1 NOTES 56 57A context for HASH DRBG can be obtained by calling: 58 59 EVP_RAND *rand = EVP_RAND_fetch(NULL, "HASH-DRBG", NULL); 60 EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand); 61 62=head1 EXAMPLES 63 64 EVP_RAND *rand; 65 EVP_RAND_CTX *rctx; 66 unsigned char bytes[100]; 67 OSSL_PARAM params[2], *p = params; 68 unsigned int strength = 128; 69 70 rand = EVP_RAND_fetch(NULL, "HASH-DRBG", NULL); 71 rctx = EVP_RAND_CTX_new(rand, NULL); 72 EVP_RAND_free(rand); 73 74 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST, SN_sha512, 0); 75 *p = OSSL_PARAM_construct_end(); 76 EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params); 77 78 EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0); 79 80 EVP_RAND_CTX_free(rctx); 81 82=head1 CONFORMING TO 83 84NIST SP 800-90A and SP 800-90B 85 86=head1 SEE ALSO 87 88L<EVP_RAND(3)>, 89L<EVP_RAND(3)/PARAMETERS> 90 91=head1 COPYRIGHT 92 93Copyright 2020-2021 The OpenSSL Project Authors. All Rights Reserved. 94 95Licensed under the Apache License 2.0 (the "License"). You may not use 96this file except in compliance with the License. You can obtain a copy 97in the file LICENSE in the source distribution or at 98L<https://www.openssl.org/source/license.html>. 99 100=cut 101