.\"	$OpenBSD: EXTENDED_KEY_USAGE_new.3,v 1.2 2016/12/25 22:15:10 schwarze Exp $
.\"
.\" Copyright (c) 2016 Ingo Schwarze <schwarze@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
.\" purpose with or without fee is hereby granted, provided that the above
.\" copyright notice and this permission notice appear in all copies.
.\"
.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
.\" MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
.\" ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
.\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
.\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
.\"
.Dd $Mdocdate: December 25 2016 $
.Dt EXTENDED_KEY_USAGE_NEW 3
.Os
.Sh NAME
.Nm EXTENDED_KEY_USAGE_new ,
.Nm EXTENDED_KEY_USAGE_free
.Nd X.509 key usage restrictions
.Sh SYNOPSIS
.In openssl/x509v3.h
.Ft EXTENDED_KEY_USAGE
.Fn EXTENDED_KEY_USAGE_new void
.Ft void
.Fn EXTENDED_KEY_USAGE_free "EXTENDED_KEY_USAGE *eku"
.Sh DESCRIPTION
By using the key usage extension, the extended key usage extension,
or both of them,
.Vt X509
end entity certificates may indicate that the key contained in them
is only intended to be used for the specified purposes.
If both extensions are present, only uses compatible with both
extensions are intended.
.Pp
.Fn EXTENDED_KEY_USAGE_new
allocates and initializes an empty
.Vt EXTENDED_KEY_USAGE
object, which is a
.Vt STACK_OF(ASN1_OBJECT)
and represents an ASN.1
.Vt ExtKeyUsageSyntax
structure defined in RFC 5280 section 4.2.1.12.
It can hold key purpose identifiers.
.Pp
.Fn EXTENDED_KEY_USAGE_free
frees
.Fa eku .
.Pp
The key usage extension uses the ASN.1 BIT STRING data type
and doesn't require any dedicated object.
.Sh RETURN VALUES
.Fn EXTENDED_KEY_USAGE_new
returns the new
.Vt EXTENDED_KEY_USAGE
object or
.Dv NULL
if an error occurs.
.Sh SEE ALSO
.Xr BASIC_CONSTRAINTS_new 3 ,
.Xr POLICYINFO_new 3 ,
.Xr X509_EXTENSION_new 3 ,
.Xr X509_new 3
.Sh STANDARDS
RFC 5280: Internet X.509 Public Key Infrastructure Certificate and
Certificate Revocation List (CRL) Profile:
.Bl -dash -compact
.It
section 4.2.1.3: Key Usage
.It
section 4.2.1.12: Extended Key Usage
.El