---
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
---

# 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 just "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.

# DEFAULT

NULL

# EXAMPLE

~~~c
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "sftp://example.com/file");
    curl_easy_setopt(curl, CURLOPT_SSH_PUBLIC_KEYFILE,
                     "/home/clarkkent/.ssh/id_rsa.pub");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
~~~

# AVAILABILITY

The "" trick was added in 7.26.0

# RETURN VALUE

Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.