PHP Extension

SFTP Authenticate with a SecureString Password and Private Key

Demonstrates the Chilkat SFtp.AuthenticateSecPwPk method, which authenticates using SecureString login and password objects together with a private key. The third argument is the SshKey private key.

Note: The private-key path is relative to the application's current working directory. Supply the path to your own key file.

Background: This is the SecureString form of two-factor SFTP authentication: the password is held encrypted in memory and combined with a private key for servers that require both. It is the most protective option when a deployment mandates two-factor SSH and you also want to minimize plaintext credential exposure in the process.

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PHP Extension

<?php

include("chilkat.php");

$success = false;

//  Demonstrates the SFtp.AuthenticateSecPwPk method, which authenticates using SecureString login
//  and password objects together with a private key.  The 1st argument is the username, the 2nd
//  is the password, and the 3rd is an SshKey private key.

$sftp = new CkSFtp();

//  Step 1: Connect the SSH transport.  Port 22 is the usual port.
$port = 22;
$success = $sftp->Connect('sftp.example.com',$port);
if ($success == false) {
    print $sftp->lastErrorText() . "\n";
    exit;
}

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
$password = 'mySshPassword';

//  Load the SSH private key.  LoadText reads the file's text, which is then imported.
$privKey = new CkSshKey();
$keyText = $privKey->loadText('qa_data/id_rsa');
if ($privKey->get_LastMethodSuccess() == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

$success = $privKey->FromOpenSshPrivateKey($keyText);
if ($success == false) {
    print $privKey->lastErrorText() . "\n";
    exit;
}

//  Place the login and password into SecureString objects.
$secureLogin = new CkSecureString();
$secureLogin->Append('mySshLogin');
$securePassword = new CkSecureString();
$securePassword->Append($password);

$success = $sftp->AuthenticateSecPwPk($secureLogin,$securePassword,$privKey);
if ($success == false) {
    print $sftp->lastErrorText() . "\n";
    exit;
}

//  Step 3: Open the SFTP subsystem.  This must be done after authentication and before any
//  file or directory operations.
$success = $sftp->InitializeSftp();
if ($success == false) {
    print $sftp->lastErrorText() . "\n";
    exit;
}

print 'Authenticated.' . "\n";

$sftp->Disconnect();

?>