title: Flexiprovider - How to encrypt/de with formatted keypair
body: <p>Im using flexiprovider to encrypt/de with asymmetric algorithm based on Elliptic Curve following this <a href="http://www.flexiprovider.de/examples/ExampleECIES.html" rel="nofollow noreferrer">tutorial</a>. With a little modification, i'm gonna convert the public and the private key into Base64 for personal purpose (like storing into the database or text file). I'm also looking at this <a href="https://stackoverflow.com/questions/19048434/flexiprovider-elliptic-curve-public-key-from-byte-array">question</a> and the answer is refer to this <a href="https://stackoverflow.com/questions/13713991/badpaddingexception-invalid-ciphertext">thread</a>. But my code are running for dekstop not in android device, android and dekstop version in java i think is a really big difference (just for clean up my question information). Ok, in my code when im going to create the formatted public key from a generated public key i got an error (i think the same problem will happen when i try to do that for the private key).
  Now, here's my code:</p>
  
  <ul>
  <li>Keypair generator class.</li>
  </ul>
  
  
  
  
  <pre><code>import org.jivesoftware.smack.util.Base64; //or whatever to convert into Base64
  import java.security.KeyPair;
  import java.security.KeyPairGenerator;
  import java.security.PrivateKey;
  import java.security.PublicKey;
  import java.security.SecureRandom;
  import java.security.Security;
  import java.security.KeyFactory;
  import javax.crypto.Cipher;   
  import de.flexiprovider.common.ies.IESParameterSpec;
  import de.flexiprovider.core.FlexiCoreProvider;
  import de.flexiprovider.ec.FlexiECProvider;
  import de.flexiprovider.ec.parameters.CurveParams;
  import de.flexiprovider.ec.parameters.CurveRegistry.BrainpoolP160r1;
  import de.flexiprovider.pki.PKCS8EncodedKeySpec;
  import de.flexiprovider.pki.X509EncodedKeySpec;
  ...
    Security.addProvider(new FlexiCoreProvider());
    Security.addProvider(new FlexiECProvider());
  
    KeyPairGenerator kpg = KeyPairGenerator.getInstance("ECIES","FlexiEC");
  
    CurveParams ecParams = new BrainpoolP160r1();
  
    kpg.initialize(ecParams, new SecureRandom());
    KeyPair keyPair = kpg.generateKeyPair();
  
    PublicKey pubKey = keyPair.getPublic();
    byte[] encod_pubK = pubKey.getEncoded();
  
    String publicKey = Base64.encodeBytes(encod_pubK);
    System.out.println("Public Key :" +publikKey);
  
    PrivateKey privKey = keyPair.getPrivate();
    byte[] encod_privK = privKey.getEncoded();
    String privateKey = Base64.encodeBytes(encod_privK);
    System.out.println("Private Key :" +privateKey);
  </code></pre>
  
  <p>From that code above im going to store the string "privateKey" and "publicKey". Now im going to encrypt the message.</p>
  
  <ul>
  <li>Sender Side</li>
  </ul>
  
  
  
  
  <pre><code>import (same as code above)
  ...
    Security.addProvider(new FlexiCoreProvider());
    Security.addProvider(new FlexiECProvider());
    Cipher cipher = Cipher.getInstance("ECIES","FlexiEC");
    IESParameterSpec iesParams = new IESParameterSpec ("AES128_CBC","HmacSHA1", null, null);
  
    byte[] decodedPubKey = Base64.decode(publicKey);
  
    X509EncodedKeySpec formatted_public = new X509EncodedKeySpec(decodedPubKey);
    KeyFactory kf = KeyFactory.getInstance("ECIES","FlexiEC");
  
    PublicKey publicKey = kf.generatePublic(formatted_public); // &lt;--- I got error when hit this row
  
    cipher.init(Cipher.ENCRYPT_MODE, publicKey, iesParams);
  
    byte[] block = "this my message".getBytes();
    System.out.println("Plaintext: "+ new String(block));
  
    byte [] Ciphered = cipher.doFinal(block);
    System.out.println("Ciphertext : "+ Base64.encodeBytes(Ciphered));
  </code></pre>
  
  <p><strong>The error</strong> from that sender code above is:</p>
  
  <pre><code>Exception in thread "main" de.flexiprovider.api.exceptions.InvalidKeySpecException:     java.lang.RuntimeException: java.security.InvalidAlgorithmParameterException: Caught IOException("Unknown named curve: 1.3.36.3.3.2.8.1.1.1")
  at de.flexiprovider.ec.keys.ECKeyFactory.generatePublic(ECKeyFactory.java:205)
  at de.flexiprovider.api.keys.KeyFactory.engineGeneratePublic(KeyFactory.java:39)
  at java.security.KeyFactory.generatePublic(KeyFactory.java:328)
  </code></pre>
  
  <p>How can i generate that public key with that named curve: 1.3.36.3.3.2.8.1.1.1 ? </p>
  
  <ul>
  <li>Recipient Side (just for another information)</li>
  </ul>
  
  <p>If the sender has been succesfully encrypt the message, now im going to decrypt the message, here's my code (but not sure if this running without an error like the sender code above):</p>
  
  
  
  
  <pre><code> byte[] decodedPrivateKey = Base64.decode(privateKey);
   PKCS8EncodedKeySpec formatted_private = new PKCS8EncodedKeySpec(decodedPrivateKey);
  
   cipher.init(Cipher.DECRYPT_MODE, privKey, iesParams);
   byte[] decryptedCipher = cipher.doFinal(Ciphered);
   System.out.println("Decrypted message : "+ new String (decryptedCipher));
  </code></pre>