PKCS8_PKEY_ADD1_ATTR(3ossl)

📦
version 15.1 · 3 versions
, in freebsd 15.1

💖 PKCS8_PKEY_ADD1_ATTR 💖

okay bestie, so this is a page from the OpenSSL manual — the 3ossl girlies, section 3, the "library functions" zone ✨. It's all about messing with attributes on a PKCS8_PRIV_KEY_INFO struct, which is giving very much "private key but with extra little tags attached" energy. iykyk 🔥

🌸 NAME 🌸

PKCS8_pkey_get0_attrs, PKCS8_pkey_add1_attr, PKCS8_pkey_add1_attr_by_NID, PKCS8_pkey_add1_attr_by_OBJ — literally the PKCS8 attribute function family 💅. Four sisters, one job: get and add attributes on your p8 struct. periodt.

🦋 SYNOPSIS 🦋

first things first, you gotta invite x509.h to the party:

#include <openssl/x509.h>

const STACK_OF(X509_ATTRIBUTE) *
PKCS8_pkey_get0_attrs(const PKCS8_PRIV_KEY_INFO *p8);
int PKCS8_pkey_add1_attr(PKCS8_PRIV_KEY_INFO *p8, X509_ATTRIBUTE *attr);
int PKCS8_pkey_add1_attr_by_NID(PKCS8_PRIV_KEY_INFO *p8, int nid, int type,
                                const unsigned char *bytes, int len);
int PKCS8_pkey_add1_attr_by_OBJ(PKCS8_PRIV_KEY_INFO *p8, const ASN1_OBJECT *obj,
                               int type, const unsigned char *bytes, int len);

no cap, just copy that block and you're so back 🫶

🎀 DESCRIPTION 🎀

okay so let's break down each one, because they're all doing slightly different things and the vibes matter:

  • PKCS8_pkey_get0_attrs() — this one reads. You hand it a const PKCS8_PRIV_KEY_INFO called p8, and it gives you back a const STACK of X509_ATTRIBUTE that's chilling inside that struct. it's giving "let me see what's in there" 🔍✨
  • PKCS8_pkey_add1_attr() — this one adds, but you gotta bring your own attribute. You pass an already-constructed X509_ATTRIBUTE attr, and it gets added to the existing PKCS8_PRIV_KEY_INFO structure p8. DIY queen behavior 💅
  • PKCS8_pkey_add1_attr_by_NID() and PKCS8_pkey_add1_attr_by_OBJ() — these two are the chefs 👑. They construct a brand-new X509_ATTRIBUTE from the arguments you passed, and then add it to the existing PKCS8_PRIV_KEY_INFO structure p8. So you don't need to build the attribute yourself — they do the cooking for you. iconic.
the difference between the two is honestly just how you identify the thing: one by nid, one by obj (ASN1_OBJECT). both take a type, bytes and len to go with it. 🧚

⭐ RETURN VALUES ⭐

slay, here's the scorecard:

  • PKCS8_pkey_add1_attr(), PKCS8_pkey_add1_attr_by_NID(), and PKCS8_pkey_add1_attr_by_OBJ() return 1 for success and 0 for failure.

that's it, that's the whole system. 1 = we ate, 0 = something went wrong bestie 😭

🌈 NOTES 🌈

little lore drop: STACK of X509_ATTRIBUTE shows up in many X509-related structures (she gets around, we love a social butterfly 🦋), and some of those structures have their own corresponding set of similar functions. so if you've seen this pattern before in another manpage — yes, it's the same vibe check, different struct.

💜 SEE ALSO 💜

  • crypto(7) — the big general one, go touch grass there if you need context 🌱

Copyright 2020 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 version is 3.5.6, dated 2026-04-07, and it's filed under PKCS8_PKEY_ADD1_ATTR(3ossl). go forth and add those attributes, you absolute main character 💅✨🎀

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