curl-curl/docs/libcurl/opts/CURLOPT_SSLCERT.md
Daniel Stenberg 08a3e8e19a
TLS: remove support for Secure Transport and BearSSL
These libraries do not support TLS 1.3 and have been marked for removal
for over a year. We want to help users select a TLS dependency that is
future-proof and reliable, and not supporting TLS 1.3 in 2025 does not
infer confidence. Users who build libcurl are likely to be served better
and get something more future-proof with a TLS library that supports
1.3.

Closes #16677
2025-06-11 07:54:19 +02:00

2.3 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol TLS-backend Added-in
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl CURLOPT_SSLCERT 3 libcurl
CURLOPT_KEYPASSWD (3)
CURLOPT_SSLCERTTYPE (3)
CURLOPT_SSLKEY (3)
TLS
OpenSSL
GnuTLS
mbedTLS
Schannel
wolfSSL
7.1

NAME

CURLOPT_SSLCERT - SSL client certificate

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERT, char *cert);

DESCRIPTION

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%

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_SSLCERT, "client.pem");
    curl_easy_setopt(curl, CURLOPT_SSLKEY, "key.pem");
    curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

%AVAILABILITY%

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).