DOKK / manpages / debian 12 / libcurl4-doc / CURLOPT_SSLKEY.3.en
CURLOPT_SSLKEY(3) curl_easy_setopt options CURLOPT_SSLKEY(3)

CURLOPT_SSLKEY - private key file for TLS and SSL client cert

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

Pass a pointer to a null-terminated string as parameter. The string should be the file name of your private key. The default format is "PEM" and can be changed with CURLOPT_SSLKEYTYPE(3).

(Windows, iOS and Mac OS X) 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.

NULL

All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

CURL *curl = curl_easy_init();
if(curl) {

curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_SSLCERT, "client.pem");
curl_easy_setopt(curl, CURLOPT_SSLKEY, "key.pem");
curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
ret = curl_easy_perform(curl);
curl_easy_cleanup(curl); }

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.

CURLOPT_SSLKEYTYPE(3), CURLOPT_SSLCERT(3),

January 2, 2023 libcurl 7.88.1