.\" zip_file_set_encryption.mdoc -- set encryption method for file
.\" Copyright (C) 2016-2017 Dieter Baron and Thomas Klausner
.\"
.\" This file is part of libzip, a library to manipulate ZIP files.
.\" The authors can be contacted at <libzip@nih.at>
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in
.\"    the documentation and/or other materials provided with the
.\"    distribution.
.\" 3. The names of the authors may not be used to endorse or promote
.\"    products derived from this software without specific prior
.\"    written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS
.\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
.\" GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
.\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
.\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd December 18, 2017
.Dt ZIP_FILE_SET_ENCRYPTION 3
.Os
.Sh NAME
.Nm zip_file_set_encryption
.Nd set encryption method for file in zip
.Sh LIBRARY
libzip (-lzip)
.Sh SYNOPSIS
.In zip.h
.Ft int
.Fn zip_file_set_encryption "zip_t *archive" "zip_uint64_t index" "zip_uint16_t method" "const char *password"
.Sh DESCRIPTION
The
.Fn zip_file_set_encryption
function sets the encryption method for the file at position
.Ar index
in the zip archive to
.Ar method
using the password
.Ar password .
The
.Ar method
is the same as returned by
.Xr zip_stat 3 .
For the
.Ar method
argument, currently only the following values are supported:
.Bl -tag -width ZIP_CM_DEFLATE_XX
.It Dv ZIP_EM_NONE
No encryption.
.It Dv ZIP_EM_AES_128
Winzip AES-128 encryption.
.It Dv ZIP_EM_AES_192
Winzip AES-192 encryption.
.It Dv ZIP_EM_AES_256
Winzip AES-256 encryption.
.El
.Pp
If
.Ar password
is
.Dv NULL ,
the default password provided by
.Xr zip_set_default_password 3
is used.
.Pp
The current encryption method for a file in a zip archive can be
determined using
.Xr zip_stat 3 .
.Sh RETURN VALUES
Upon successful completion 0 is returned.
Otherwise, \-1 is returned and the error information in
.Ar archive
is set to indicate the error.
.Sh ERRORS
.Fn zip_file_set_encryption
fails if:
.Bl -tag -width Er
.It Bq Er ZIP_ER_ENCRNOTSUPP
Unsupported compression method requested.
.It Bq Er ZIP_ER_INVAL
.Ar index
is not a valid file index in
.Ar archive ,
or the argument combination is invalid.
.It Bq Er ZIP_ER_MEMORY
Required memory could not be allocated.
.It Bq Er ZIP_ER_RDONLY
Read-only zip file, no changes allowed.
.El
.Sh SEE ALSO
.Xr libzip 3 ,
.Xr zip_set_default_password 3 ,
.Xr zip_stat 3
.Sh HISTORY
.Fn zip_file_set_encryption
was added in libzip 1.2.0.
.Sh AUTHORS
.An -nosplit
.An Dieter Baron Aq Mt dillo@nih.at
and
.An Thomas Klausner Aq Mt tk@giga.or.at