X509V3_EXT_NCONF_NID(3ossl)

💖 X509V3_EXT_NCONF_NID 💖

okay bestie, so you found yourself in the 3ossl section of the OpenSSL manual, staring at a page called X509V3_EXT_NCONF_NID, and you're like... what is this. Don't worry, I got you. This is the page about X509V3_EXT_nconf and X509V3_EXT_nconf_nid, the little functions that build X.509 certificate extensions out of OpenSSL configuration. Slay. Let's go. 🦋

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✨ NAME ✨

X509V3_EXT_nconf, X509V3_EXT_nconf_nid — functions to create X.509 certificate extensions based on OpenSSL configuration 💅

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🌸 SYNOPSIS 🌸

#include <openssl/x509v3.h>

X509_EXTENSION *X509V3_EXT_nconf_nid(CONF *conf, X509V3_CTX *ctx, int ext_nid,
    const char *value);
X509_EXTENSION *X509V3_EXT_nconf(CONF *conf, X509V3_CTX *ctx, const char *name,
    const char *value);

like, that's the whole entrance exam right there. 🎀

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👑 DESCRIPTION 👑

So here's the tea. X509V3_EXT_nconf_nid() and X509V3_EXT_nconf() create a requested X.509 extension — and the way you tell them which extension is either by name or by ext_nid, correspondingly. Meanwhile value holds the string that's gonna get encoded. Iconic.

Then we have the supporting cast:

• conf — the configuration information where additional data will be read from. Bestie, conf will typically come from a config file. 💾
• ctx — and if this one is null, the default one is used. no cap.

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🫶 NOTES 🫶

okay so real talk: normally you should not be calling these functions directly. 🙈

For many extensions they will not produce the expected results without a suitably configured context (the conf and ctx arguments) that specifies the target object, issuer data, etc. It's giving "don't try this at home unless you actually know what you're doing." 😭

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⭐ RETURN VALUES ⭐

• X509V3_EXT_nconf() and X509V3_EXT_nconf_nid() return an X509_EXTENSION object on success 🎉
• and NULL on failure 💀

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💜 COPYRIGHT 💜

Copyright 2026 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>.

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and that's the whole vibe check, bestie 🧚✨ this was the 3ossl page for OpenSSL version 3.5.9, dated 2026-09-29 — periodt, go forth and configure your extensions responsibly 💖🌸🎀