CURLOPT_PROXY_SSL_CIPHER_LIST3

Usage

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSL_CIPHER_LIST,
                          char *list);

Overview

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 to the HTTPS proxy. 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_PROXY_TLS13_CIPHERS(3).

A valid example of a cipher list 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.

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 internal built-in list.

Protocols

This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. only

This option works only with the following TLS backends: OpenSSL, Rustls, Schannel, mbedTLS and wolfSSL

Examples

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

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).