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)