.\" $OpenBSD: DSA_size.3,v 1.8 2022/07/13 21:44:23 schwarze Exp $
.\" full merge up to: OpenSSL 61f805c1 Jan 16 01:01:46 2018 +0800
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.\" Copyright (c) 2022 Ingo Schwarze <schwarze@openbsd.org>
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.Dd $Mdocdate: July 13 2022 $
.Dt DSA_SIZE 3
.Os
.Sh NAME
.Nm DSA_size ,
.Nm DSA_bits
.Nd get DSA signature or key size
.Sh SYNOPSIS
.In openssl/dsa.h
.Ft int
.Fo DSA_size
.Fa "const DSA *dsa"
.Fc
.Ft int
.Fo DSA_bits
.Fa "const DSA *dsa"
.Fc
.Sh DESCRIPTION
.Fn DSA_size
returns the maximum size of an ASN.1 encoded DSA signature for the key
.Fa dsa
in bytes.
It can be used to determine how much memory must be allocated for a DSA
signature.
.Pp
.Fa dsa->q
must not be
.Dv NULL .
.Pp
.Fn DSA_bits
returns the number of significant bits in the public domain parameter
.Fa p
contained in
.Fa dsa .
This is also the number of bits in the public key.
.Sh RETURN VALUES
.Fn DSA_size
returns the size of the signature in bytes.
.Pp
.Fn DSA_bits
returns the size of the public key in bits.
.Sh SEE ALSO
.Xr DSA_get0_pqg 3 ,
.Xr DSA_new 3 ,
.Xr DSA_security_bits 3 ,
.Xr DSA_sign 3
.Sh HISTORY
.Fn DSA_size
first appeared in SSLeay 0.6.0 and has been available since
.Ox 2.4 .
.Pp
.Fn DSA_bits
first appeared in OpenSSL 1.1.0 and has been available since
.Ox 7.1 .