X509V3_EXT_GET_NID(3)      Library Functions Manual      X509V3_EXT_GET_NID(3)

NAME
     X509V3_EXT_get_nid, X509V3_EXT_get - retrieve X.509v3 certificate
     extension methods

SYNOPSIS
     #include <openssl/x509v3.h>

     const X509V3_EXT_METHOD *
     X509V3_EXT_get_nid(int nid);

     const X509V3_EXT_METHOD *
     X509V3_EXT_get(X509_EXTENSION *ext);

DESCRIPTION
     An X.509v3 certificate extension contains an Object Identifier (OID), a
     boolean criticality indicator, and an opaque extension value (an
     ASN1_OCTET_STRING) whose meaning is determined by the OID.  The library's
     X509V3_EXT_METHOD type, which is not yet documented in detail, contains a
     numeric identifier to represent the OID and various handlers for
     encoding, decoding, printing, and configuring the extension's value.
     Criticality is handled separately, for example as an argument to
     X509V3_add1_i2d(3).

RETURN VALUES
     X509V3_EXT_get_nid() returns the X509V3_EXT_METHOD corresponding to the
     numeric identifier nid, or NULL if there is none.

     X509V3_EXT_get() returns the X509V3_EXT_METHOD associated with the
     extension type of ext, or NULL if there is none.

SEE ALSO
     i2s_ASN1_ENUMERATED_TABLE(3), OBJ_create(3),
     X509_EXTENSION_get_object(3), X509V3_get_d2i(3)

STANDARDS
     RFC 5280: Internet X.509 Public Key Infrastructure Certificate and
     Certificate Revocation List (CRL) Profile
     -   section 4.2: Certificate Extensions

HISTORY
     These functions first appeared in OpenSSL 0.9.2b and have been available
     since OpenBSD 2.6.

CAVEATS
     LibreSSL only supports built-in extension methods.  Other implementations
     have incomplete support for custom extension methods, whose API is not
     threadsafe, does not affect the behavior of X509_verify_cert(3), and has
     various other surprising quirks.  Both functions prefer built-in methods
     over custom methods with the same OID.

Linux 6.10.10-arch1-1            May 14, 2024            Linux 6.10.10-arch1-1