CURLOPT_PROXY_SSLKEYTYPE(3) Library Functions ManualCURLOPT_PROXY_SSLKEYTYPE(3)
NAME
CURLOPT_PROXY_SSLKEYTYPE - type of the proxy private key file
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLKEYTYPE, char *type);
DESCRIPTION
This option is for connecting to an HTTPS proxy, not an HTTPS server.
Pass a pointer to a null-terminated string as parameter. The string
should be the format of your private key. Supported formats are "PEM",
"DER", "ENG" and "PROV" (the latter added in curl 8.12.0).
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.
PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS,
POP3S, SMTPS etc.
This option works only with the following TLS backends: BearSSL, OpenSSL
and wolfSSL
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_PROXY, "https://proxy");
curl_easy_setopt(curl, CURLOPT_PROXY_SSLCERT, "client.pem");
curl_easy_setopt(curl, CURLOPT_PROXY_SSLKEY, "key.pem");
curl_easy_setopt(curl, CURLOPT_PROXY_SSLKEYTYPE, "PEM");
curl_easy_setopt(curl, CURLOPT_PROXY_KEYPASSWD, "s3cret");
res = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.52.0
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).
SEE ALSO
CURLOPT_PROXY_SSLCERT(3), CURLOPT_PROXY_SSLKEY(3), CURLOPT_SSLKEYTYPE(3)
libcurl 2026-07-12 CURLOPT_PROXY_SSLKEYTYPE(3)
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