---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_SSH_PUBLIC_KEYFILE
Section: 3
Source: libcurl
See-also:
  - CURLOPT_SSH_AUTH_TYPES (3)
  - CURLOPT_SSH_PRIVATE_KEYFILE (3)
Protocol:
  - SFTP
  - SCP
Added-in: 7.16.1
---

# NAME

CURLOPT_SSH_PUBLIC_KEYFILE - public key file for SSH auth

# SYNOPSIS

~~~c
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSH_PUBLIC_KEYFILE,
                          char *filename);
~~~

# DESCRIPTION

Pass a char pointer pointing to a *filename* for your public key. If not used,
libcurl defaults to **$HOME/.ssh/id_dsa.pub** if the HOME environment variable
is set, and "id_dsa.pub" in the current directory if HOME is not set.

If NULL (or an empty string) is passed to this option, libcurl passes no
public key to the SSH library, which then rather derives it from the private
key. If the SSH library cannot derive the public key from the private one and
no public one is provided, 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 public 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

NULL

# %PROTOCOLS%

# EXAMPLE

~~~c
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_PUBLIC_KEYFILE,
                     "/home/clarkkent/.ssh/id_rsa.pub");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
~~~

# HISTORY

The "" trick was added in 7.26.0

# %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).
