CURLOPT_PROXY_SSLKEY(3)    Library Functions Manual    CURLOPT_PROXY_SSLKEY(3)

NAME
       CURLOPT_PROXY_SSLKEY - private key file for HTTPS proxy client cert

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLKEY, char *keyfile);

DESCRIPTION
       Pass a pointer to a null-terminated string as parameter. The string
       should be the filename of your private key used for connecting to the
       HTTPS proxy. The default format is "PEM" and can be changed with
       CURLOPT_PROXY_SSLKEYTYPE(3).

       (Windows, iOS and macOS) This option is ignored by Secure Transport and
       Schannel SSL backends because they expect the private key to be already
       present in the key chain or PKCS#12 file containing the certificate.

       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

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

       This option works only with the following TLS backends: OpenSSL,
       Schannel, 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_PROXY, "https://proxy");
           curl_easy_setopt(curl, CURLOPT_PROXY_SSLCERT, "client.pem");
           curl_easy_setopt(curl, CURLOPT_PROXY_SSLKEY, "key.pem");
           curl_easy_setopt(curl, CURLOPT_PROXY_KEYPASSWD, "s3cret");
           res = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY
       Added in curl 7.52.0

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).

SEE ALSO
       CURLOPT_PROXY_SSLCERT(3), CURLOPT_PROXY_SSLKEYTYPE(3),
       CURLOPT_SSLCERT(3), CURLOPT_SSLKEY(3), CURLOPT_SSLKEYTYPE(3)

libcurl                           2025-06-04           CURLOPT_PROXY_SSLKEY(3)