CURLOPT_KEYPASSWD - passphrase to private key

Added in curl 7.17.0

NULL

Pass a pointer to a null-terminated string as parameter. It is used as the password required to use the CURLOPT_SSLKEY(3) or CURLOPT_SSH_PRIVATE_KEYFILE(3) private key. You never need a passphrase to load a certificate but you need one to load your private key. 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.

int main(void) { CURL *curl = curl_easy_init(); if(curl) { CURLcode res; curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin"); curl_easy_setopt(curl, CURLOPT_SSLCERT, "client.pem"); curl_easy_setopt(curl, CURLOPT_SSLKEY, "key.pem"); curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "superman"); res = curl_easy_perform(curl); curl_easy_cleanup(curl); } }

This option was known as CURLOPT_SSLKEYPASSWD up to 7.16.4 and CURLOPT_SSLCERTPASSWD up to 7.9.2.

CURLOPT_KEYPASSWD - passphrase to private key

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

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).

CURLOPT_SSH_PRIVATE_KEYFILE(3), CURLOPT_SSLKEY(3) libcurl 2025-06-16 CURLOPT_KEYPASSWD(3)

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