Android™

SSH Authenticate with Secure Strings

Demonstrates SSH password authentication using SecureString objects, with the credentials read from an encrypted JSON config file and decrypted directly into secure strings rather than being hard-coded in source.

Background: This shows the shape of a genuinely careful credential flow: secrets live outside the source in encrypted form, and are decrypted straight into a SecureString so a plaintext copy never sits in an ordinary string. A SecureString keeps the value encrypted in memory under a randomly generated session key. In production the decryption key itself would come from a secure source — a key vault, an OS keystore, or the environment — rather than being a literal as shown here for illustration.

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// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    boolean success = false;

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

    //  Demonstrates SSH password authentication using SecureString objects, with the credentials
    //  read from an encrypted config file rather than hard-coded in source.

    //  Imagine the login and password were previously encrypted and saved in a JSON config file:
    //  {
    //    "ssh_login": "2+qylFfC56Ck7OQQt/U2/w==",
    //    "ssh_password": "5neIq9Jmn0E3p71N6Yc8TA=="
    //  }
    CkJsonObject json = new CkJsonObject();
    success = json.LoadFile("qa_data/passwords/ssh.json");
    if (success == false) {
        Log.i(TAG, json.lastErrorText());
        return;
        }

    //  These are the encryption settings used when the credentials were encrypted.  In a real
    //  application the key would come from a secure source, not a literal.
    CkCrypt2 crypt = new CkCrypt2();
    crypt.put_CryptAlgorithm("aes");
    crypt.put_CipherMode("cbc");
    crypt.put_KeyLength(128);
    crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex");
    crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex");
    crypt.put_EncodingMode("base64");

    //  Decrypt directly into SecureString objects.  The values remain encrypted in memory, now
    //  under a randomly generated session key.
    CkSecureString ssLogin = new CkSecureString();
    CkSecureString ssPassword = new CkSecureString();
    crypt.DecryptSecureENC(json.stringOf("ssh_login"),ssLogin);
    crypt.DecryptSecureENC(json.stringOf("ssh_password"),ssPassword);

    CkSsh ssh = new CkSsh();
    int port = 22;
    success = ssh.Connect("ssh.example.com",port);
    if (success == false) {
        Log.i(TAG, ssh.lastErrorText());
        return;
        }

    //  Authenticate using the secure strings.
    success = ssh.AuthenticateSecPw(ssLogin,ssPassword);
    if (success == false) {
        Log.i(TAG, ssh.lastErrorText());
        return;
        }

    Log.i(TAG, "SSH authentication successful.");

    ssh.Disconnect();

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}