EVP_KDF-HMAC-DRBG(7ossl)

📦
version 15.1 · 2 versions
, in freebsd 15.1

✨ NAME ✨

  • EVP_KDF-HMAC-DRBG — the HMAC DRBG DETERMINISTIC EVP_KDF implementation. Yup, that's the whole vibe of this EVP_KDF-HMAC-DRBG(7ossl) page, bestie. 💖

🌈 DESCRIPTION 🌈

Support for a deterministic HMAC DRBG using the EVP_KDF API. It’s similar to EVP_RAND-HMAC-DRBG(7), but it uses fixed values for its entropy and nonce values. This is used to generate the deterministic nonce value required by ECDSA and DSA (as defined in RFC 6979). No cap, that determinism is the whole point. 🔥

🪪 Identity

"HMAC-DRBG-KDF" is the name for this implementation; it can be used with the EVP_KDF_fetch() function. That’s the name to remember, iykyk. 👑

🎛️ Supported parameters

The supported parameters are:

  • "digest" (OSSL_DRBG_PARAM_DIGEST) <UTF8 string> — one of the supported parameters, bestie.
  • "properties" (OSSL_DRBG_PARAM_PROPERTIES) <UTF8 string> — another supported parameter. These parameters work as described in "PARAMETERS" in EVP_KDF(3).
  • "entropy" (OSSL_KDF_PARAM_HMACDRBG_ENTROPY) <octet string> — sets the entropy bytes supplied to the HMAC-DRBG.
  • "nonce" (OSSL_KDF_PARAM_HMACDRBG_NONCE) <octet string> — sets the nonce bytes supplied to the HMAC-DRBG.

📝 NOTES 📝

A context for KDF HMAC DRBG can be obtained by calling:

EVP_KDF *kdf = EVP_KDF_fetch(NULL, "HMAC-DRBG-KDF", NULL);
EVP_KDF_CTX *kdf_ctx = EVP_KDF_CTX_new(kdf, NULL);

Literally just like that. Copy it, paste it, live your truth. 💅

🧚 CONFORMING TO 🧚

RFC 6979. Periodt. ⭐

👀 SEE ALSO 👀

Go peek at those if you want the full lore. 🫶

🌸 HISTORY 🌸

The EVP_KDF-HMAC-DRBG functionality was added in OpenSSL 3.2. It’s giving fresh-from-the-release-notes main character energy. 🦋

Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.

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>.

xoxo, OpenSSL 3.5.6 / 2026-04-07 — EVP_KDF-HMAC-DRBG(7ossl) 💅✨

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