---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_SSL_CIPHER_LIST
Section: 3
Source: libcurl
See-also:
  - CURLOPT_PROXY_SSL_CIPHER_LIST (3)
  - CURLOPT_PROXY_TLS13_CIPHERS (3)
  - CURLOPT_SSLVERSION (3)
  - CURLOPT_TLS13_CIPHERS (3)
  - CURLOPT_USE_SSL (3)
Protocol:
  - TLS
TLS-backend:
  - OpenSSL
  - Schannel
  - wolfSSL
  - mbedTLS
  - rustls
  - GnuTLS
Added-in: 7.9
---

# NAME

CURLOPT_SSL_CIPHER_LIST - ciphers to use for TLS

# SYNOPSIS

~~~c
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSL_CIPHER_LIST, char *list);
~~~

# DESCRIPTION

Pass a char pointer, pointing to a null-terminated string holding the list of
cipher suites to use for the TLS 1.2 (1.1, 1.0) connection. The list must
be syntactically correct, it consists of one or more cipher suite strings
separated by colons.

For setting TLS 1.3 ciphers see CURLOPT_TLS13_CIPHERS(3).

A valid example of a cipher list with OpenSSL is:
~~~
"ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:"
"ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305"
~~~

For Schannel, you can use this option to set algorithms but not specific
cipher suites. Refer to the ciphers lists document for algorithms.

GnuTLS has the concept of a
[priority string](https://gnutls.org/manual/html_node/Priority-Strings.html)
which has its own syntax and keywords. The string set via
CURLOPT_SSL_CIPHER_LIST(3) directly influences the priority setting.

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.

Using this option multiple times makes the last set string override the
previous ones. Set it to NULL to disable its use again.

# DEFAULT

NULL, use built-in list

# %PROTOCOLS%

# EXAMPLE

~~~c
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_SSL_CIPHER_LIST,
                     "ECDHE-ECDSA-CHACHA20-POLY1305:"
                     "ECDHE-RSA-CHACHA20-POLY1305");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
~~~

# HISTORY

OpenSSL support added in 7.9.
wolfSSL support added in 7.53.0.
Schannel support added in 7.61.0.
mbedTLS support added in 8.8.0.
Rustls support added in 8.10.0.

Since curl 8.10.0 returns CURLE_NOT_BUILT_IN when not supported.

# %AVAILABILITY%

# RETURN VALUE

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see
libcurl-errors(3).
