Android Open Source - CipherChat Start Chat Reply

From Project

Back to project page CipherChat.

License

The source code is released under:

MIT License

If you think the Android project CipherChat listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.

Java Source Code

package com.desperate.common.replies;
/*from   w w w . ja va 2s.c o m*/
import java.io.UnsupportedEncodingException;

import javax.crypto.spec.SecretKeySpec;

import com.desperate.common.NoncePacket;
import com.desperate.common.Utilities;

/**
 * Implements the following messages of the Needham-Shroeder-revisited protocol:
 * <p>
 * 2. <b>B -> A:</b> Eb( A, Rb ) (Ks is null)<br>
 * 5. <b>A -> B:</b> Eb( A, Rb , Ks)
 * 
 * @author SIRS-RAR
 * 
 */
public class StartChatReply extends ReplyMessage {

  private static final long serialVersionUID = 709775960818919208L;

  /**
   * Creates a message with a ciphered nonce packet inside. To be used by B on step 2 of Needham-Shroeder revisited.
   * 
   * @param packet
   *            Packet with freshness information and the name of A
   * @param key
   *            Secret key of B
   * @throws Exception
   *             if the ciphering failed for any reason
   */
  public StartChatReply(NoncePacket packet, SecretKeySpec key) throws Exception {

    this.cipheredNoncePacket = Utilities.cipherObject(packet, key);
  }

  /**
   * Creates a message with an already ciphered nonce packet inside. To be used by A on step 5 of Needham-Shroeder revisited.
   * 
   * @param cipheredNoncePacket
   *            ciphered freshness packet sent by B on step 2
   */
  public StartChatReply(byte[] cipheredNoncePacket) {
    this.cipheredNoncePacket = cipheredNoncePacket;
  }

  /** Is actually a {@linkplain com.desperate.common.NoncePacket NoncePacket}. */
  public byte[] cipheredNoncePacket;

  @Override
  public String getStringToHMAC() {

    try {
      return timestamp + new String(cipheredNoncePacket, Utilities.charset);
    } catch (UnsupportedEncodingException e) {

      e.printStackTrace();
      throw new RuntimeException(e);
    }
  }
}

Java Source Code List