X509_GET_PUBKEY(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

🌸 NAME 🌸

okay bestie, welcome to the X509_GET_PUBKEY(3ossl) page 💖 this one is literally all about getting or setting the public key on a certificate or certificate request. The main-character functions are:

  • X509_get_pubkey
  • X509_get0_pubkey
  • X509_set_pubkey
  • X509_get_X509_PUBKEY
  • X509_REQ_get_pubkey
  • X509_REQ_get0_pubkey
  • X509_REQ_set_pubkey
  • X509_REQ_get_X509_PUBKEY

✨ SYNOPSIS ✨

#include <openssl/x509.h>

EVP_PKEY *X509_get_pubkey(X509 *x);
EVP_PKEY *X509_get0_pubkey(const X509 *x);
int X509_set_pubkey(X509 *x, EVP_PKEY *pkey);
X509_PUBKEY *X509_get_X509_PUBKEY(const X509 *x);

EVP_PKEY *X509_REQ_get_pubkey(X509_REQ *req);
EVP_PKEY *X509_REQ_get0_pubkey(X509_REQ *req);
int X509_REQ_set_pubkey(X509_REQ *x, EVP_PKEY *pkey);
X509_PUBKEY *X509_REQ_get_X509_PUBKEY(X509_REQ *x);

🦋 DESCRIPTION 🦋

So X509_get_pubkey() tries to decode the public key for certificate x. If it slays and succeeds, it returns the public key as an EVP_PKEY pointer with its reference count incremented 🔥 that means the returned key must be freed up after use, bestie. X509_get0_pubkey() is similar, except it does not increment the reference count of the returned EVP_PKEY, so it must not be freed up after use 🙈

X509_get_X509_PUBKEY() returns an internal pointer to the X509_PUBKEY structure which encodes the certificate of x. The returned value must not be freed up after use 💅

X509_set_pubkey() attempts to set the public key for certificate x to pkey. The key pkey should be freed up after use 🫶

X509_REQ_get_pubkey(), X509_REQ_get0_pubkey(), X509_REQ_set_pubkey() and X509_REQ_get_X509_PUBKEY() are similar but operate on certificate request req 🌈

🎀 NOTES 🎀

The first time a public key is decoded, the EVP_PKEY structure is cached in the certificate or certificate request itself. Subsequent calls return the cached structure with its reference count incremented to improve performance ⭐ no cap, that's the whole note.

💜 RETURN VALUES 💜

  • X509_get_pubkey(), X509_get0_pubkey(), X509_get_X509_PUBKEY(), X509_REQ_get_pubkey() and X509_REQ_get_X509_PUBKEY() return a public key or NULL if an error occurred 😭
  • X509_set_pubkey() and X509_REQ_set_pubkey() return 1 for success and 0 for failure 💀

🔥 SEE ALSO 🔥

Copyright 2015-2016 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>.

💖 signed, sealed, and slayed by OpenSSL 3.5.0, dated 2026-09-25 — mwah 💋

📦 where this page comes from