X509_GET_SUBJECT_NAME(3SSL)

📦
version 4.0.3 · 13 versions
, in ubuntu stonking

✨ X509_GET_SUBJECT_NAME 💅 — the 3SSL one, bestie

okay so this whole page lives in the OpenSSL manual, section 3SSL, and it's the girlies' guide to getting X509_NAME hashes and getting/setting issuer or subject names. she's a lot of functions but honestly? iconic. let's go 🫶

🌸 NAME 🌸

X509_NAME_hash_ex, X509_NAME_hash, X509_get_subject_name, X509_set_subject_name, X509_subject_name_hash, X509_get_issuer_name, X509_set_issuer_name, X509_issuer_name_hash, X509_REQ_get_subject_name, X509_REQ_set_subject_name, X509_ACERT_get0_issuerName, X509_ACERT_set1_issuerName, X509_CRL_get_issuer, X509_CRL_set_issuer_name — get X509_NAME hashes or get and set issuer or subject names ✨

it's giving "one page, fourteen functions, zero notes". periodt.

🎀 SYNOPSIS 🎀

#include <openssl/x509.h>

unsigned long X509_NAME_hash_ex(const X509_NAME *x, OSSL_LIB_CTX *libctx,
                                const char *propq, int *ok);

const X509_NAME *X509_get_subject_name(const X509 *x);
int X509_set_subject_name(X509 *x, const X509_NAME *name);
unsigned long X509_subject_name_hash(const X509 *x);

const X509_NAME *X509_get_issuer_name(const X509 *x);
int X509_set_issuer_name(X509 *x, const X509_NAME *name);
unsigned long X509_issuer_name_hash(const X509 *x);

const X509_NAME *X509_REQ_get_subject_name(const X509_REQ *req);
int X509_REQ_set_subject_name(X509_REQ *req, const X509_NAME *name);

const X509_NAME *X509_CRL_get_issuer(const X509_CRL *crl);
int X509_CRL_set_issuer_name(X509_CRL *x, const X509_NAME *name);

#include <openssl/x509_acert.h>

X509_NAME *X509_ACERT_get0_issuerName(const X509_ACERT *x);
int X509_ACERT_set1_issuerName(X509_ACERT *x, const X509_NAME *name);
⚠️ okay bestie, listen. this next macro has been deprecated since OpenSSL 3.0. you can hide it entirely by defining OPENSSL_API_COMPAT with a suitable version value — check openssl_user_macros(7) for the deets.
#define X509_NAME_hash(x) X509_NAME_hash_ex(x, NULL, NULL, NULL)

💖 DESCRIPTION 💖

X509_NAME_hash_ex() hands you a hash value of the name x, or 0 if it flops — using whatever library context libctx and property query propq you gave her. the ok result argument can be NULL, or else she uses it to drop 1 for success and 0 for failure. and when does failure happen, you ask? on a malloc error, or if there's literally no SHA1 implementation available to be found. 😭

X509_NAME_hash() also returns a hash value of name x, or 0 on failure, except she's using the default library context and the default property query.

X509_get_subject_name() returns the subject name of certificate x. 💅 the returned value is an internal pointer which MUST NOT be freed — hands off, don't you dare. and x MUST NOT be NULL.

X509_set_subject_name() sets the issuer name of certificate x to name (yes, it really says issuer there, we're just reading it out loud, no editing bestie). the name parameter gets copied internally, so you should free it up yourself once you don't need it anymore.

X509_subject_name_hash() returns a hash value of the subject name of certificate x.

X509_get_issuer_name(), X509_set_issuer_name(), and X509_issuer_name_hash() are literally identical to X509_get_subject_name(), X509_set_subject_name(), and X509_subject_name_hash() — the only glow-up difference is that they relate to the issuer name of x instead.

same energy for X509_REQ_get_subject_name(), X509_REQ_set_subject_name(), X509_ACERT_get0_issuerName(), X509_ACERT_set1_issuerName(), X509_CRL_get_issuer() and X509_CRL_set_issuer_name() — they get or set the subject or issuer names of certificate requests of CRLs respectively. (that's what the page says, fr fr 🦋)

and here's a lil plot twist: since attribute certificates don't have a subject name, you can only set the issuer name. no subject for you, ACERT. 🚫 for details on setting X509_ACERT holder identities, go see X509_ACERT_set0_holder_entityName(3).

⭐ RETURN VALUES ⭐

  • X509_get_subject_name(), X509_get_issuer_name(), X509_REQ_get_subject_name(), X509_ACERT_get0_issuerName() and X509_CRL_get_issuer() — they hand you back an X509_NAME pointer. 💖
  • X509_NAME_hash_ex(), X509_NAME_hash(), X509_subject_name_hash() and X509_issuer_name_hash() — they return the first four bytes of the SHA1 hash value, converted to unsigned long in little endian order, or 0 on failure. 🔥
  • X509_set_subject_name(), X509_set_issuer_name(), X509_REQ_set_subject_name(), X509_ACERT_get0_issuerName() and X509_CRL_set_issuer_name() — 1 for success, 0 for failure. that's it, that's the whole vibe check.

💀 BUGS 💀

bestie. if X509_NAME_hash(), X509_subject_name_hash(), or X509_issuer_name_hash() returns 0, it stays completely unclear whether that's the real hash value or just a failure. 😭 so like… better use X509_NAME_hash_ex() instead. no cap.

🌈 SEE ALSO 🌈

d2i_X509(3), ERR_get_error(3), d2i_X509(3) (yes she's listed twice, we don't ask questions 👑), X509_CRL_get0_by_serial(3), X509_get0_signature(3), X509_get_ext_d2i(3), X509_get_extension_flags(3), X509_get_pubkey(3), X509_NAME_add_entry_by_txt(3), X509_NAME_ENTRY_get_object(3), X509_NAME_get_index_by_NID(3), X509_NAME_print_ex(3), X509_new(3), X509_sign(3), X509V3_get_d2i(3), X509_verify_cert(3)

🧚 HISTORY 🧚

  • X509_REQ_get_subject_name() is a function in OpenSSL 1.1.0 and a macro in earlier versions.
  • X509_CRL_get_issuer() is a function in OpenSSL 1.1.0. It was previously added in OpenSSL 1.0.0 as a macro.
  • X509_NAME_hash() was turned into a macro and deprecated in OpenSSL 3.0.
  • X509_ACERT_get0_issuerName(), X509_ACERT_set1_issuerName() were added in OpenSSL 3.4.

Copyright 2015-2026 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.

and that's the whole page, bestie 💜 this was the X509_GET_SUBJECT_NAME(3SSL) manual from OpenSSL version 4.0.3, dated 2026-09-29 — go forth and hash responsibly 🎀✨

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