.\" $OpenBSD: X509_get0_signature.3,v 1.5 2018/03/23 23:18:17 schwarze Exp $
.\" selective merge up to:
.\" OpenSSL man3/X509_get0_signature 2f7a2520 Apr 25 17:28:08 2017 +0100
.\"
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
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.Dd $Mdocdate: March 23 2018 $
.Dt X509_GET0_SIGNATURE 3
.Os
.Sh NAME
.Nm X509_get0_signature ,
.Nm X509_REQ_get0_signature ,
.Nm X509_CRL_get0_signature ,
.Nm X509_get0_tbs_sigalg ,
.Nm X509_get_signature_nid ,
.Nm X509_REQ_get_signature_nid ,
.Nm X509_CRL_get_signature_nid
.Nd signature information
.Sh SYNOPSIS
.In openssl/x509.h
.Ft void
.Fo X509_get0_signature
.Fa "const ASN1_BIT_STRING **psig"
.Fa "const X509_ALGOR **palg"
.Fa "const X509 *x"
.Fc
.Ft void
.Fo X509_REQ_get0_signature
.Fa "const X509_REQ *req"
.Fa "const ASN1_BIT_STRING **psig"
.Fa "const X509_ALGOR **palg"
.Fc
.Ft void
.Fo X509_CRL_get0_signature
.Fa "const X509_CRL *crl"
.Fa "const ASN1_BIT_STRING **psig"
.Fa "const X509_ALGOR **palg"
.Fc
.Ft const X509_ALGOR *
.Fo X509_get0_tbs_sigalg
.Fa "const X509 *x"
.Fc
.Ft int
.Fo X509_get_signature_nid
.Fa "const X509 *x"
.Fc
.Ft int
.Fo X509_REQ_get_signature_nid
.Fa "const X509_REQ *req"
.Fc
.Ft int
.Fo X509_CRL_get_signature_nid
.Fa "const X509_CRL *crl"
.Fc
.Sh DESCRIPTION
.Fn X509_get0_signature ,
.Fn X509_REQ_get0_signature ,
and
.Fn X509_CRL_get0_signature
set
.Pf * Fa psig
to the signature and
.Pf * Fa palg
to the signature algorithm of
.Fa x ,
.Fa req ,
or
.Fa crl ,
respectively.
.Fn X509_get0_tbs_sigalg
returns the signature algorithm in the signed portion of
.Fa x .
The values returned are internal pointers
that must not be freed by the caller.
.Pp
.Fn X509_get_signature_nid ,
.Fn X509_REQ_get_signature_nid ,
and
.Fn X509_CRL_get_signature_nid
return the NID corresponding to the signature algorithm of
.Fa x ,
.Fa req ,
or
.Fa crl ,
respectively.
.Pp
These functions provide lower level access to the signature
for cases where an application wishes to analyse or generate a
signature in a form where
.Xr X509_sign 3
is not appropriate, for example in a non-standard or unsupported format.
.Sh SEE ALSO
.Xr OBJ_obj2nid 3 ,
.Xr X509_ALGOR_new 3 ,
.Xr X509_CRL_get0_by_serial 3 ,
.Xr X509_CRL_new 3 ,
.Xr X509_get_pubkey 3 ,
.Xr X509_get_subject_name 3 ,
.Xr X509_get_version 3 ,
.Xr X509_new 3 ,
.Xr X509_REQ_new 3 ,
.Xr X509_sign 3 ,
.Xr X509_verify_cert 3
.Sh HISTORY
.Fn X509_get0_signature
and
.Fn X509_get_signature_nid
first appeared in OpenSSL 1.0.2.
.Fn X509_REQ_get0_signature ,
.Fn X509_CRL_get0_signature ,
.Fn X509_get0_tbs_sigalg ,
.Fn X509_REQ_get_signature_nid ,
and
.Fn X509_CRL_get_signature_nid
first appeared in OpenSSL 1.1.0.
All these functions have been available since
.Ox 6.3 .