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/* license: https://mit-license.org
* ==============================================================================
* The MIT License (MIT)
*
* Copyright (c) 2019 Albert Moky
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
* ==============================================================================
*/
package chat.dim.impl;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import chat.dim.crypto.SymmetricKey;
import chat.dim.plugins.AESKey;
/**
* Symmetric Cryptography Key
* ~~~~~~~~~~~~~~~~~~~~~~~~~~
* This class is used to encrypt or decrypt message data
*
* key data format: {
* algorithm : "AES", // "DES", ...
* data : "{BASE64_ENCODE}",
* ...
* }
*/
public abstract class SymmetricKeyImpl extends CryptographyKeyImpl implements SymmetricKey {
protected SymmetricKeyImpl(Map dictionary) {
super(dictionary);
}
private static final byte[] promise = "Moky loves May Lee forever!".getBytes();
@Override
public boolean equals(Object other) {
if (super.equals(other)) {
// same dictionary
return true;
} else if (other instanceof SymmetricKey) {
// check by encryption
SymmetricKey key = (SymmetricKey) other;
byte[] ciphertext = key.encrypt(promise);
byte[] plaintext = decrypt(ciphertext);
return Arrays.equals(plaintext, promise);
} else {
// null or unknown object
return false;
}
}
//-------- Runtime --------
private static Map symmetricKeyClasses = new HashMap<>();
@SuppressWarnings("unchecked")
public static void register(String algorithm, Class clazz) {
// check whether clazz is subclass of SymmetricKey
assert SymmetricKey.class.isAssignableFrom(clazz); // asSubclass
symmetricKeyClasses.put(algorithm, clazz);
}
private static Class keyClass(Map dictionary) {
// get subclass by key algorithm
String algorithm = (String) dictionary.get("algorithm");
return symmetricKeyClasses.get(algorithm);
}
@SuppressWarnings("unchecked")
public static SymmetricKey getInstance(Object object) throws ClassNotFoundException {
if (object == null) {
return null;
} else if (object instanceof SymmetricKey) {
return (SymmetricKey) object;
}
assert object instanceof Map;
Map dictionary = (Map) object;
Class clazz = keyClass(dictionary);
if (clazz != null) {
// create instance by subclass (with algorithm)
return (SymmetricKey) createInstance(clazz, dictionary);
}
throw new ClassNotFoundException("key error: " + dictionary);
}
public static SymmetricKey generate(String algorithm) throws ClassNotFoundException {
Map dictionary = new HashMap<>();
dictionary.put("algorithm", algorithm);
return getInstance(dictionary);
}
static {
// AES
register(AES, AESKey.class); // default
register("AES/CBC/PKCS7Padding", AESKey.class);
// DES
// ...
}
}
