.\" generated by cd2nroff 0.1 from CURLOPT_SSLKEY.md
.TH CURLOPT_SSLKEY 3 "2024-07-29" libcurl
.SH NAME
CURLOPT_SSLKEY \- private key file for TLS and SSL client cert
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLKEY, char *keyfile);
.fi
.SH DESCRIPTION
Pass a pointer to a null\-terminated string as parameter. The string should be
the filename of your private key. The default format is "PEM" and can be
changed with \fICURLOPT_SSLKEYTYPE(3)\fP.

(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.
.SH DEFAULT
NULL
.SH 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
.SH EXAMPLE
.nf
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);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.9.3
.SH RETURN VALUE
Returns CURLE_OK if TLS is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.
.SH SEE ALSO
.BR CURLOPT_SSLCERT (3),
.BR CURLOPT_SSLKEYTYPE (3),
.BR CURLOPT_SSLKEY_BLOB (3)