JAVA加密算法系列-DESCoder

package ***;


import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;


/**
 * DES安全编码组件
 */
public abstract class DESCoder extends EnBaseCoder {

    public static final String ALGORITHM = "DES";

    /**
     * 转换密钥<br>
     * 
     * @param key
     * @return
     * @throws Exception
     */
    private static Key toKey(byte[] key) throws Exception {
        DESKeySpec dks = new DESKeySpec(key);
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(ALGORITHM);
        SecretKey secretKey = keyFactory.generateSecret(dks);

        return secretKey;
    }

    /**
     * 解密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decrypt(byte[] data, String key) throws Exception {
        Key k = toKey(decryptBASE64(key));

        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, k);

        return cipher.doFinal(data);
    }

    /**
     * 加密
     * 
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encrypt(byte[] data, String key) throws Exception {
        Key k = toKey(decryptBASE64(key));
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, k);

        return cipher.doFinal(data);
    }

    /**
     * 生成密钥
     * 
     * @return
     * @throws Exception
     */
    public static String initKey() throws Exception {
        return initKey(null);
    }

    /**
     * 生成密钥
     * 
     * @param seed
     * @return
     * @throws Exception
     */
    public static String initKey(String seed) throws Exception {
        SecureRandom secureRandom = null;

        if (seed != null) {
            secureRandom = new SecureRandom(decryptBASE64(seed));
        } else {
            secureRandom = new SecureRandom();
        }

        KeyGenerator kg = KeyGenerator.getInstance(ALGORITHM);
        kg.init(secureRandom);

        SecretKey secretKey = kg.generateKey();

        return encryptBASE64(secretKey.getEncoded());
    }
    public static void main(String[] args) throws Exception {

        String inputStr = "DES";
        String key = DESCoder.initKey();
        System.err.println("原文:	" + inputStr);

        System.err.println("密钥:	" + key);

        byte[] inputData = inputStr.getBytes();
        inputData = DESCoder.encrypt(inputData, key);
        
        System.out.println("加密后:	" + DESCoder.encryptBASE64(inputData));

        byte[] outputData = DESCoder.decrypt(inputData, key);
        String outputStr = new String(outputData);
        System.out.println("解密后:	" + outputStr);

    
    }
}