---
name: "CURLOPT_SSH_PRIVATE_KEYFILE"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_SSH_PRIVATE_KEYFILE"
---

# CURLOPT\_SSH\_PRIVATE\_KEYFILE(3)

private key file for SSH auth

## NAME

CURLOPT\_SSH\_PRIVATE\_KEYFILE - private key file for SSH auth

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_PRIVATE_KEYFILE,
                          char *filename);
```

## DESCRIPTION

Pass a char pointer pointing to a *filename* for your private key. If not used, libcurl defaults to **$HOME/.ssh/id\_rsa** or **$HOME/.ssh/id\_dsa** if the HOME environment variable is set, and in the current directory if HOME is not set.

If the file is password-protected, set the password with *[CURLOPT\_KEYPASSWD(3)](/CURLOPT_KEYPASSWD/3.md)*.

The SSH library derives the public key from this private key when possible. If the SSH library cannot derive the public key from the private one and no public one is provided with *[CURLOPT\_SSH\_PUBLIC\_KEYFILE(3)](/CURLOPT_SSH_PUBLIC_KEYFILE/3.md)*, the transfer fails.

The application does not have to keep the string around after setting this option.

This option is used to set up a new connection only. The private key is used when libcurl establishes a new SSH connection; once that connection has been successfully set up and verified, it is deemed vetted and may be reused by libcurl even if this option is changed.

## DEFAULT

As explained above

## PROTOCOLS

This functionality affects scp and sftp

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/file");
    curl_easy_setopt(curl, CURLOPT_SSH_PRIVATE_KEYFILE,
                     "/home/clarkkent/.ssh/id_rsa");
    curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "password");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in curl 7.16.1

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_SSH\_AUTH\_TYPES**(3)](/CURLOPT_SSH_AUTH_TYPES/3.md), [**CURLOPT\_SSH\_PUBLIC\_KEYFILE**(3)](/CURLOPT_SSH_PUBLIC_KEYFILE/3.md)