CURLOPT_SSLCERT(3)

CURLOPT_SSLCERT3

Ssl client certificate

Usage

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

Overview

Pass a pointer to a null-terminated string as parameter. The string should be the filename of your client certificate. The default format is PEM but can be changed with CURLOPT_SSLCERTTYPE(3).

(Schannel) Client certificates can be specified by a path expression to a certificate store. (You can import PFX to a store first). You can use "<store location>\<store name>\<thumbprint>" to refer to a certificate in the system certificates store, for example, "CurrentUser\MY\934a7ac6f8a5d5". The thumbprint is usually a SHA-1 hex string which you can see in certificate details. Following store locations are supported: CurrentUser, LocalMachine, CurrentService, Services, CurrentUserGroupPolicy, LocalMachineGroupPolicy, LocalMachineEnterprise. Schannel also support P12 certificate file, with the string P12 specified with CURLOPT_SSLCERTTYPE(3).

When using a client certificate, you most likely also need to provide a private key with CURLOPT_SSLKEY(3).

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. only

All TLS backends support this option.

Examples

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

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).

Releases

7 releases since Debian 8 (Jessie); the text changed 6 times.

  1. 8
  2. 9
  3. 10
  4. 11
  5. 12
  6. 13
  7. Arch

Availability

Added in curl 7.1

From curl 8.23.0-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.