EVP_RAND-HASH-DRBG

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).

"fips-indicator" (OSSL_DRBG_PARAM_FIPS_APPROVED_INDICATOR) <integer>

"digest-check" (OSSL_DRBG_PARAM_FIPS_DIGEST_CHECK) <integer>

These parameters work as described in "PARAMETERS" in provider-rand(7).

When the FIPS provider is installed using the -no_drbg_truncated_digests option to fipsinstall, only these digests are permitted (as per FIPS 140-3 IG D.R https://csrc.nist.gov/CSRC/media/Projects/cryptographic-module-validation-program/documents/fips%20140-3/FIPS%20140-3%20IG.pdf):

The default HASH-DRBG implementation attempts to fetch the required internal algorithms from the provider they are built into (eg the default provider) regardless of the properties provided. Should the provider not implement the required algorithms then properties will be used to find a different implementation.

SHA-1

SHA2-256

SHA2-512

SHA3-256

SHA3-512

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, NULL);

 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);

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

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

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