---
name: "X509_check_issued"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/X509_check_issued"
---

# X509\_check\_issued(3ssl)

checks if certificate is apparently issued by another certificate

## NAME

X509\_check\_issued - checks if certificate is apparently issued by another certificate

## SYNOPSIS

```
 #include <openssl/x509v3.h>
 int X509_check_issued(X509 *issuer, X509 *subject);
```

## DESCRIPTION

**X509\_check\_issued()** checks if certificate *subject* was apparently issued using (CA) certificate *issuer*. This function takes into account not only matching of the issuer field of *subject* with the subject field of *issuer*, but also compares all sub-fields of the **authorityKeyIdentifier** extension of *subject*, as far as present, with the respective **subjectKeyIdentifier**, serial number, and issuer fields of *issuer*, as far as present. It also checks if the **keyUsage** field (if present) of *issuer* allows certificate signing. It does not actually check the certificate signature. An error is returned if the *issuer* or the *subject* are incomplete certificates.

## RETURN VALUES

**X509\_check\_issued()** returns **X509\_V\_OK** if all checks are successful or some **X509\_V\_ERR\*** constant to indicate an error.

## SEE ALSO

**X509\_verify\_cert**(3), **X509\_verify**(3), **X509\_check\_ca**(3), **openssl-verify**(1), **X509\_self\_signed**(3)

## COPYRIGHT

Copyright 2015-2021 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\>.