1 /*

     2  * otr4j, the open source java otr library.

     3  *

     4  * Distributable under LGPL license.

     5  * See terms of license at gnu.org.

     6  */

     7 package net.java.otr4j.io.messages;

     8 

     9 import java.io.IOException;

    10 import java.util.Arrays;

    11 

    12 import net.java.otr4j.OtrException;

    13 import net.java.otr4j.crypto.OtrCryptoEngineImpl;

    14 import net.java.otr4j.io.SerializationUtils;

    15 

    16 /**

    17  * 

    18  * @author George Politis

    19  */

    20 public class SignatureMessage extends AbstractEncodedMessage {

    21 	// Fields.

    22 	public byte[] xEncrypted;

    23 	public byte[] xEncryptedMAC;

    24 

    25 	// Ctor.

    26 	protected SignatureMessage(int messageType, int protocolVersion,

    27 			byte[] xEncrypted, byte[] xEncryptedMAC) {

    28 		super(messageType, protocolVersion);

    29 		this.xEncrypted = xEncrypted;

    30 		this.xEncryptedMAC = xEncryptedMAC;

    31 	}

    32 

    33 	public SignatureMessage(int protocolVersion, byte[] xEncrypted,

    34 			byte[] xEncryptedMAC) {

    35 		this(MESSAGE_SIGNATURE, protocolVersion, xEncrypted, xEncryptedMAC);

    36 	}

    37 

    38 	// Memthods.

    39 	public byte[] decrypt(byte[] key) throws OtrException {

    40 		return new OtrCryptoEngineImpl().aesDecrypt(key, null, xEncrypted);

    41 	}

    42 

    43 	public boolean verify(byte[] key) throws OtrException {

    44 		// Hash the key.

    45 		byte[] xbEncrypted;

    46 		try {

    47 			xbEncrypted = SerializationUtils.writeData(xEncrypted);

    48 		} catch (IOException e) {

    49 			throw new OtrException(e);

    50 		}

    51 

    52 		byte[] xEncryptedMAC = new OtrCryptoEngineImpl().sha256Hmac160(

    53 				xbEncrypted, key);

    54 		// Verify signature.

    55 		return Arrays.equals(xEncryptedMAC, xEncryptedMAC);

    56 	}

    57 

    58 	@Override

    59 	public int hashCode() {

    60 		final int prime = 31;

    61 		int result = super.hashCode();

    62 		result = prime * result + Arrays.hashCode(xEncrypted);

    63 		result = prime * result + Arrays.hashCode(xEncryptedMAC);

    64 		return result;

    65 	}

    66 

    67 	@Override

    68 	public boolean equals(Object obj) {

    69 		if (this == obj)

    70 			return true;

    71 		if (!super.equals(obj))

    72 			return false;

    73 		if (getClass() != obj.getClass())

    74 			return false;

    75 		SignatureMessage other = (SignatureMessage) obj;

    76 		if (!Arrays.equals(xEncrypted, other.xEncrypted))

    77 			return false;

    78 		if (!Arrays.equals(xEncryptedMAC, other.xEncryptedMAC))

    79 			return false;

    80 		return true;

    81 	}

    82 }