Dart

SSH Public Key Authentication

Demonstrates authenticating with an SSH server using public-key authentication. A private key is loaded into an SshKey object and passed to AuthenticatePk. The matching public key must already be installed on the server for the account.

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

Background: Public-key authentication is the standard for unattended and automated SSH: the private key never leaves the client, the server merely trusts the corresponding public key, and no reusable password crosses the wire. SshKey imports several formats — OpenSSH PEM keys via FromOpenSshPrivateKey and PuTTY .ppk files via FromPuttyPrivateKey — encrypted or not. For an encrypted key, set the Password property before importing. Note that LoadText is only a convenience for reading a text file into a string; it does not itself load the key.

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Dart

import 'package:chilkat/chilkat.dart';

void main() {
  // This example requires the Chilkat API to have been previously unlocked.
  // See Global Unlock Sample for sample code.

  // Demonstrates authenticating with an SSH server using public-key authentication.  The matching
  // public key must already be installed on the SSH server for the account.

  final ssh = CkSsh();

  // Timeouts, in milliseconds.
  ssh.connectTimeoutMs = 5000;
  ssh.readTimeoutMs = 15000;

  final hostname = 'ssh.example.com';
  final port = 22;
  try {
    ssh.connect(hostname, port);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // LoadText is a convenience method that reads any text file into a string.  It does not itself
  // load the key.
  final key = CkSshKey();
  final String privKeyText;
  try {
    privKeyText = key.loadText('qa_data/my_private_key.pem');
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  // Import the private key.  Both OpenSSH and PuTTY formats are supported, encrypted or not.
  // This example loads an unencrypted OpenSSH-format key; for a PuTTY .ppk file, call
  // FromPuttyPrivateKey instead.  For an encrypted key, set key.Password before importing.
  try {
    key.fromOpenSshPrivateKey(privKeyText);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  try {
    ssh.authenticatePk('mySshLogin', key);
  } on ChilkatException catch (e) {
    print(e.lastErrorText);
    return;
  }

  print('Public-key authentication successful.');

  ssh.disconnect();
}