(Android™) Generate RSA Key for SFTP

See more SSH Key Examples

Generates an 2048-bit RSA key for SSH/SFTP. Your application will use the generated private key. The public key is to be uploaded to the server and stored in the ".ssh" directory located under the HOME directory of the SSH/SFTP user account.

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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);

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

    CkSshKey key = new CkSshKey();

    int numBits = 2048;
    int exponent = 65537;
    boolean success = key.GenerateRsaKey(numBits,exponent);
    if (success != true) {
        Log.i(TAG, "Bad params passed to RSA key generation method.");
        return;
        }

    // Note: Generating a public/private key pair is CPU intensive
    // and may take a short amount of time (more than few seconds,
    // but less than a minute).

    String exportedKey;
    boolean exportEncrypted;

    // Export the RSA private key to encrypted PuTTY format:
    key.put_Password("secret");
    exportEncrypted = true;
    exportedKey = key.toPuttyPrivateKey(exportEncrypted);
    success = key.SaveText(exportedKey,"qa_output/rsa_privkey_putty_encrypted.ppk");

    // Export the public key to openSSH format..
    exportedKey = key.toOpenSshPublicKey();
    success = key.SaveText(exportedKey,"qa_output/id_rsa.pub");

    // Sample id_rsa.pub:
    // ssh-rsa
    // AAAAB3NzaC1yc2EAAAADAQABAAA.....6tK3+vjwX/YC9dIXUz2Z 

    Log.i(TAG, "Finished.  Upload the id_rsa.pub to your .ssh directory located on the SSH/SFTP server under your user account's HOME directory");
    Log.i(TAG, "(Your HOME directory is the default directory you are in when you login via an SSH terminal.)");

    // After the id_rsa.pub is uploaded to your user account on the SSH/SFTP server, you can authenticate using the private key.
    // Your application will load the private key (.ppk) as shown here: Load SSH/SFTP Private Key .ppk
    // and then authenticate by calling AuthenticatePk (or AuthenticatePwPk).

  }

  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."
  }
}