des.java

200多个自己编的java程序,大家可以学一下.

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * @author leo
 * @since jkd1.4
 * 
 * TODO To change the template for this generated type comment go to Window -
 * Preferences - Java - Code Style - Code Templates
 */
public class DESAlgorithm {

    private static String algorithm = "DESede";

    /**
     * generator a SecretKey
     * 
     * @param keyByte
     * @return SecreKey
     * @throws Exception
     */
    public static SecretKey genDESKey(byte[] keyByte) throws Exception {
        SecretKey key = new SecretKeySpec(keyByte, algorithm);
        return key;
    }

    /**
     * encode String in des
     * 
     * @param key
     * @param crypt
     * @return @throws
     *         Exception
     */
    public static byte[] desEncrypt(SecretKey key, String crypt)
            throws Exception {
        return desEncrypt(key, crypt.getBytes());
    }

    /**
     * encode byte array in des
     * 
     * @param key
     * @param crypt
     * @return byte[]
     * @throws Exception
     */
    public static byte[] desEncrypt(SecretKey key, byte[] crypt)
            throws Exception {
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.ENCRYPT_MODE, key);
        return cipher.doFinal(crypt);
    }

    /**
     * decode String in des
     * 
     * @param key
     * @param crypt
     * @return @throws
     *         Exception
     */
    public static byte[] desDecrypt(SecretKey key, String crypt)
            throws Exception {
        return desDecrypt(key, crypt.getBytes());
    }

    /**
     * decode byte array in des
     * 
     * @param key
     * @param crypt
     * @return byte[]
     * @throws Exception
     */
    public static byte[] desDecrypt(SecretKey key, byte[] crypt)
            throws Exception {
        Cipher cipher = Cipher.getInstance(algorithm);
        cipher.init(Cipher.DECRYPT_MODE, key);
        return cipher.doFinal(crypt);
    }

    /**
     * @return Returns the algorithm.
     */
    public static String getAlgorithm() {
        return algorithm;
    }

    /**
     * @param algorithm
     *            The algorithm to set.
     */
    public static void setAlgorithm(String algorithm) {
        DESAlgorithm.algorithm = algorithm;
    }
}