001/* 002 * Trident - A Multithreaded Server Alternative 003 * Copyright 2014 The TridentSDK Team 004 * 005 * Licensed under the Apache License, Version 2.0 (the "License"); 006 * you may not use this file except in compliance with the License. 007 * You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package net.tridentsdk.server.netty.packet; 019 020import javax.crypto.Cipher; 021import java.security.Key; 022import java.security.KeyPair; 023import java.security.KeyPairGenerator; 024import java.security.NoSuchAlgorithmException; 025 026/** 027 * Produces RSA encryption digests 028 * 029 * <p>Used to create encrypted packets that the server sends to clients</p> 030 * 031 * @author The TridentSDK Team 032 */ 033public final class RSA { 034 private RSA() { 035 } 036 037 /** 038 * Generates a KeyPair with the specified amount of bits using an RSA cipher 039 * 040 * @param bits the bits in the final digest for the KeyPair 041 * @return the KeyPair that has the specified bits and RSA cipher 042 * @throws NoSuchAlgorithmException if RSA cipher is removed in the future 043 */ 044 public static KeyPair generate(int bits) throws NoSuchAlgorithmException { 045 KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA"); 046 keyGen.initialize(bits); 047 048 return keyGen.generateKeyPair(); 049 } 050 051 /** 052 * Decrypts the data into the cipher with the given key 053 * 054 * @param data the data to be ciphered 055 * @param key the key to use for initialization 056 * @return the decrypted bytes 057 * @throws Exception if something happens to occur 058 */ 059 public static byte[] decrypt(byte[] data, Key key) throws Exception { 060 Cipher cipher = Cipher.getInstance("RSA"); 061 cipher.init(Cipher.DECRYPT_MODE, key); 062 063 return cipher.doFinal(data); 064 } 065}