OSSL_CRMF_PBMP_NEW(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 NAME

okay so bestie, meet OSSL_CRMF_pbm_new and OSSL_CRMF_pbmp_new — the OpenSSL functions that produce a Password-Based MAC (PBM), aka the whole "prove you know the secret without yeeting the secret" vibe. This is the 3ossl manual, and yes we're reading it together, grab a snack. 🍓

✨ SYNOPSIS

#include <openssl/crmf.h>

int OSSL_CRMF_pbm_new(OSSL_LIB_CTX *libctx, const char *propq,
                      const OSSL_CRMF_PBMPARAMETER *pbmp,
                      const unsigned char *msg, size_t msglen,
                      const unsigned char *sec, size_t seclen,
                      unsigned char **mac, size_t *maclen);

OSSL_CRMF_PBMPARAMETER *OSSL_CRMF_pbmp_new(OSSL_LIB_CTX *libctx, size_t saltlen,
                                           int owfnid, size_t itercnt,
                                           int macnid);

🦋 DESCRIPTION

the main character: OSSL_CRMF_pbm_new()

So this one generates a PBM (Password-Based MAC) based on the PBM parameters you hand it in pbmp, the message msg, and the secret sec, plus the respective lengths msglen and seclen. 💖

The optional library context libctx and the propq parameter may be used to influence the selection of the MAC algorithm referenced in the pbmp — and the docs literally point you to "ALGORITHM FETCHING" in crypto(7) for the full tea on that, iykyk. ☕

On success it writes the address of the newly allocated MAC via the mac reference parameter, and writes the length via the maclen reference parameter — unless it's NULL. Slay. 🔥

the builder babe: OSSL_CRMF_pbmp_new()

This one initializes and returns a new PBMParameter structure with:

  • a new random salt of given length saltlen 🧂
  • OWF (one-way function) NID owfnid
  • OWF iteration count itercnt
  • MAC NID macnid

The library context libctx parameter may be used to select the provider for the random number generation (DRBG), and it may be NULL for the default. Fabulous. ✨

🌸 NOTES

Okay this part is giving important, listen up 👑

The algorithms for the OWF (one-way function) and for the MAC (message authentication code) may be any with a NID defined in <openssl/objects.h>. As specified by RFC 4210, these should include NID_hmac_sha1. No cap. 💅

RFC 4210 recommends that the salt SHOULD be at least 8 bytes (64 bits) long, where 16 bytes is common. Bestie, go big or go home, 16 is the vibe. 🌈

The iteration count must be at least 100, as stipulated by RFC 4211, and is limited to at most 100000 to avoid DoS through manipulated or otherwise malformed input. This is not a drill — respect the ceiling, it's there to protect you from chaos merchants. 💀

🎀 RETURN VALUES

  • OSSL_CRMF_pbm_new() returns 1 on success, 0 on error.
  • OSSL_CRMF_pbmp_new() returns a new and initialized OSSL_CRMF_PBMPARAMETER structure, or NULL on error.

Like, either it ate or it flopped. 🙈

⭐ EXAMPLES

        OSSL_CRMF_PBMPARAMETER *pbm = NULL;
        unsigned char *msg = "Hello";
        unsigned char *sec = "SeCrEt";
        unsigned char *mac = NULL;
        size_t maclen;

        if ((pbm = OSSL_CRMF_pbmp_new(16, NID_sha256, 500, NID_hmac_sha1) == NULL))
            goto err;
        if (!OSSL_CRMF_pbm_new(pbm, msg, 5, sec, 6, &mac, &maclen))
            goto err;

There it is — the whole ritual, exactly as written. Copy it verbatim, don't get creative with it. 🫶

👑 SEE ALSO

(the source material, the lore, the origin story 📜)

🧚 HISTORY

The OpenSSL CRMF support was added in OpenSSL 3.0. A classic, an icon, a legend. ⭐

Copyright 2007-2021 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>.

and that's the whole page, bestie!! 💖 this was OSSL_CRMF_PBMP_NEW(3ossl) — manual for OpenSSL 3.5.0, dated 2026-09-25. now go forth and MAC responsibly, mwah 🎀✨

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