EVP_RAND-HASH-DRBG.7ossl - Man Page

The HASH DRBG EVP_RAND implementation

Description

Support for the hash deterministic random bit generator through the EVP_RAND API.

Identity

“HASH-DRBG” is the name for this implementation; it can be used with the EVP_RAND_fetch() function.

Supported parameters

The supported parameters are:

“state” (OSSL_RAND_PARAM_STATE) <integer>
“strength” (OSSL_RAND_PARAM_STRENGTH) <unsigned integer>
“max_request” (OSSL_RAND_PARAM_MAX_REQUEST) <unsigned integer>
“reseed_requests” (OSSL_DRBG_PARAM_RESEED_REQUESTS) <unsigned integer>
“reseed_time_interval” (OSSL_DRBG_PARAM_RESEED_TIME_INTERVAL) <integer>
“min_entropylen” (OSSL_DRBG_PARAM_MIN_ENTROPYLEN) <unsigned integer>
“max_entropylen” (OSSL_DRBG_PARAM_MAX_ENTROPYLEN) <unsigned integer>
“min_noncelen” (OSSL_DRBG_PARAM_MIN_NONCELEN) <unsigned integer>
“max_noncelen” (OSSL_DRBG_PARAM_MAX_NONCELEN) <unsigned integer>
“max_perslen” (OSSL_DRBG_PARAM_MAX_PERSLEN) <unsigned integer>
“max_adinlen” (OSSL_DRBG_PARAM_MAX_ADINLEN) <unsigned integer>
“reseed_counter” (OSSL_DRBG_PARAM_RESEED_COUNTER) <unsigned integer>
“properties” (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string>
“digest” (OSSL_DRBG_PARAM_DIGEST) <UTF8 string>

These parameters work as described in “PARAMETERS” in EVP_RAND(3).

Notes

A context for HASH DRBG can be obtained by calling:

 EVP_RAND *rand = EVP_RAND_fetch(NULL, "HASH-DRBG", NULL);
 EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand);

Examples

 EVP_RAND *rand;
 EVP_RAND_CTX *rctx;
 unsigned char bytes[100];
 OSSL_PARAM params[2], *p = params;
 unsigned int strength = 128;

 rand = EVP_RAND_fetch(NULL, "HASH-DRBG", NULL);
 rctx = EVP_RAND_CTX_new(rand, NULL);
 EVP_RAND_free(rand);

 *p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_DIGEST, SN_sha512, 0);
 *p = OSSL_PARAM_construct_end();
 EVP_RAND_instantiate(rctx, strength, 0, NULL, 0, params);

 EVP_RAND_generate(rctx, bytes, sizeof(bytes), strength, 0, NULL, 0);

 EVP_RAND_CTX_free(rctx);

Conforming to

NIST SP 800-90A and SP 800-90B

See Also

EVP_RAND(3), “PARAMETERS” in EVP_RAND(3)

Referenced By

EVP_RAND.3ossl(3).

2021-09-09 3.0.0 OpenSSL