CURLOPT_SSL_CIPHER_LIST(3) Library Functions Manual
NAME
CURLOPT_SSL_CIPHER_LIST - ciphers to use for TLS
SYNOPSIS
#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 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 RC4-SHA,
SHA1+DES, TLSv1 and DEFAULT. The default list is normally set when you
compile OpenSSL.
For wolfSSL, valid examples of cipher lists include ECDHE-RSA-RC4-SHA,
AES256-SHA:AES256-SHA256, etc.
For mbedTLS and BearSSL, valid examples of cipher lists include
ECDHE-RSA-CHACHA20-POLY1305:ECDHE-RSA-AES128-GCM-SHA256, or when using
IANA names
TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256:TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
etc. With mbedTLS and 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.
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.
DEFAULT
NULL, use built-in list
PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS,
POP3S, SMTPS etc.
This option works only with the following TLS backends: BearSSL,
GnuTLS, OpenSSL, Schannel, Secure Transport, mbedTLS and wolfSSL
EXAMPLE
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, "TLSv1");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
HISTORY
Added in 7.9, in 7.83.0 for BearSSL, in 8.8.0 for mbedTLS
AVAILABILITY
Added in curl 7.9
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.
SEE ALSO
CURLOPT_PROXY_SSL_CIPHER_LIST(3), CURLOPT_PROXY_TLS13_CIPHERS(3),
CURLOPT_SSLVERSION(3), CURLOPT_TLS13_CIPHERS(3), CURLOPT_USE_SSL(3)
libcurl 2024-08-05 CURLOPT_SSL_CIPHER_LIST(3)
curl 8.9.1 - Generated Mon Aug 5 12:49:30 CDT 2024