.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_SSL_CIPHER_LIST 3 "January 02, 2023" "libcurl 7.88.1" "curl_easy_setopt options"

.SH NAME
CURLOPT_SSL_CIPHER_LIST \- ciphers to use for TLS
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CIPHER_LIST, char *list);
.fi
.SH DESCRIPTION
Pass a char *, pointing to a null-terminated string holding the list of
ciphers to use for the SSL connection. The list must be syntactically correct,
it consists of one or more cipher strings separated by colons. Commas or
spaces are also acceptable separators but colons are normally used, \&!, \&-
and \&+ can be used as operators.

For OpenSSL and GnuTLS valid examples of cipher lists include \fBRC4-SHA\fP,
\fBSHA1+DES\fP, \fBTLSv1\fP and \fBDEFAULT\fP. The default list is normally
set when you compile OpenSSL.

For NSS, valid examples of cipher lists include \fBrsa_rc4_128_md5\fP,
\fBrsa_aes_128_sha\fP, etc. With NSS you do not add/remove ciphers. If one uses
this option then all known ciphers are disabled and only those passed in are
enabled.

For WolfSSL, valid examples of cipher lists include \fBECDHE-RSA-RC4-SHA\fP,
\fBAES256-SHA:AES256-SHA256\fP, etc.

For BearSSL, valid examples of cipher lists include
\fBECDHE-RSA-CHACHA20-POLY1305:ECDHE-RSA-AES128-GCM-SHA256\fP, or when using IANA names
\fBTLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256\fP,
etc.
With BearSSL you do not add/remove ciphers. If one uses this option then all
known ciphers are disabled and only those passed in are enabled.

you will find more details about cipher lists on this URL:

 https://curl.se/docs/ssl-ciphers.html

The application does not have to keep the string around after setting this
option.
.SH DEFAULT
NULL, use internal default
.SH PROTOCOLS
All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
  curl_easy_setopt(curl, CURLOPT_SSL_CIPHER_LIST, "TLSv1");
  ret = curl_easy_perform(curl);
  curl_easy_cleanup(curl);
}
.fi
.SH AVAILABILITY
Added in 7.9, in 7.83.0 for BearSSL

If built TLS enabled.
.SH RETURN VALUE
Returns CURLE_OK if TLS is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.
.SH "SEE ALSO"
.BR CURLOPT_TLS13_CIPHERS "(3), " CURLOPT_SSLVERSION "(3), "
.BR CURLOPT_PROXY_SSL_CIPHER_LIST "(3), " CURLOPT_PROXY_TLS13_CIPHERS "(3), "
.BR CURLOPT_USE_SSL "(3), "