.\" generated by cd2nroff 0.1 from CURLOPT_SSL_CIPHER_LIST.md
.TH CURLOPT_SSL_CIPHER_LIST 3 "2024-11-07" libcurl
.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 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 \fICURLOPT_TLS13_CIPHERS(3)\fP.

A valid example of a cipher list is:
.nf
"ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:"
"ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305"
.fi

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

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.
.SH DEFAULT
NULL, use built\-in list
.SH PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

This option works only with the following TLS backends:
BearSSL, OpenSSL, Schannel, Secure Transport, mbedTLS, rustls and wolfSSL
.SH EXAMPLE
.nf
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);
  }
}
.fi
.SH HISTORY
OpenSSL support added in 7.9.
wolfSSL support added in 7.53.0.
Schannel support added in 7.61.0.
Secure Transport support added in 7.77.0.
BearSSL support added in 7.83.0.
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.
.SH AVAILABILITY
Added in curl 7.9
.SH RETURN VALUE
Returns CURLE_OK if supported, CURLE_NOT_BUILT_IN otherwise.
.SH SEE ALSO
.BR CURLOPT_PROXY_SSL_CIPHER_LIST (3),
.BR CURLOPT_PROXY_TLS13_CIPHERS (3),
.BR CURLOPT_SSLVERSION (3),
.BR CURLOPT_TLS13_CIPHERS (3),
.BR CURLOPT_USE_SSL (3)