EVP_RAND-JITTER(7ossl)

💅 NAME 💅

okay so bestie, this is EVP_RAND-JITTER from the 7ossl manual — the randomness seed source EVP_RAND implementation. no cap, that's the whole name.

✨ DESCRIPTION ✨

This is support for deterministic random number generator seeding through the EVP_RAND API. periodt.

This software seed source produces randomness based on tiny CPU "jitter" fluctuations. It's giving "chaos but make it cryptographic" 💫.

It is available when OpenSSL is compiled with enable-jitter option. When available it is listed in openssl list -random-generators and openssl info -seeds. iykyk.

🪪 Identity

"JITTER" is the name for this implementation; it can be used with the EVP_RAND_fetch() function. main character name energy.

🎚️ 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>

These parameters work as described in "PARAMETERS" in EVP_RAND(3). copy that, bestie.

🗒️ NOTES

A context for the seed source can be obtained by calling:

EVP_RAND *rand = EVP_RAND_fetch(NULL, "JITTER", NULL);
EVP_RAND_CTX *rctx = EVP_RAND_CTX_new(rand, NULL);

The enable-jitter option was added in OpenSSL 3.4. noted noted.

By specifying the enable-fips-jitter configuration option, the FIPS provider will use an internal jitter source for its entropy. okay but be careful: enabling this option will cause the FIPS provider to operate in a non-compliant mode unless an entropy assessment ESV (https://csrc.nist.gov/Projects/cryptographic-module-validation-program/entropy-validations) and validation through the CMVP (https://csrc.nist.gov/projects/cryptographic-module-validation-program) are additionally conducted. This option was added in OpenSSL 3.5. this is the important caveat, fr fr.

🌸 EXAMPLES 🌸

Bestie, here's the full example, verbatim:

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

/* Create and instantiate a seed source */
rand = EVP_RAND_fetch(NULL, "JITTER", NULL);
seed = EVP_RAND_CTX_new(rand, NULL);
EVP_RAND_instantiate(seed, strength, 0, NULL, 0, NULL);
EVP_RAND_free(rand);

/* Feed this into a DRBG */
rand = EVP_RAND_fetch(NULL, "CTR-DRBG", NULL);
rctx = EVP_RAND_CTX_new(rand, seed);
EVP_RAND_free(rand);

/* Configure the DRBG */
*p++ = OSSL_PARAM_construct_utf8_string(OSSL_DRBG_PARAM_CIPHER,
                                        SN_aes_256_ctr, 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);
EVP_RAND_CTX_free(seed);

👀 SEE ALSO

• EVP_RAND(3)
• "PARAMETERS" in EVP_RAND(3)

©️ COPYRIGHT

Copyright 2024 The OpenSSL Project Authors. All Rights Reserved. respect the authors.

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at https://www.openssl.org/source/license.html. legal stuff but make it cute.

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okay bestie that's the whole page, you ate 💅 — this was EVP_RAND-JITTER(7ossl) from OpenSSL 3.5.0, dated 2026-09-25 🎀🦋.