CURLOPT_PROXY_SSL_CIPHER_LIST - ciphers to use for HTTPS proxy

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

Pass a char pointer, pointing to a null-terminated string holding the list of ciphers to use for the connection to the HTTPS proxy. 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.

Find more details about cipher lists on this URL:

The application does not have to keep the string around after setting this option.

NULL, use internal default

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

int main(void)
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "");
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost");
    curl_easy_setopt(curl, CURLOPT_PROXY_SSL_CIPHER_LIST, "TLSv1");
    res = curl_easy_perform(curl);

Added in 7.52.0, in 7.83.0 for BearSSL, in 8.8.0 for mbedTLS

If built TLS enabled.

Returns CURLE_OK if TLS is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.


2024-05-22 libcurl