java des加密 解密

import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class CryptKit {

    private final static String DES = "DES" ;

    public static void main(String args[]) throws Exception {
        String str = encrypt( "The cold night" , "12345678" );
        System.out.println(str);
        String str2 = decrypt( "63B121C4EA212F8BC74E8113BDFBFB81" , "12345678" );
        System.out.println(str2);
    }

    // 加密
    public static byte [] encrypt( byte [] data, byte [] key) throws Exception {
        Cipher cipher = Cipher.getInstance(DES);
        DESKeySpec ds = new DESKeySpec(key);
        SecureRandom sr = new SecureRandom();
        SecretKeyFactory skfactory = SecretKeyFactory.getInstance(DES);
        SecretKey skey = skfactory.generateSecret(ds);
        cipher.init(Cipher.ENCRYPT_MODE, skey, sr);
        byte [] b = cipher.doFinal(data);
        return b;
    }

    // 加密
    public static String encrypt(String data, String key) throws Exception {
        return byte2hex(encrypt(data.getBytes(), key.getBytes()));
    }

    // 解密
    public static byte [] decrypt( byte [] data, byte [] key) throws Exception {
        Cipher cipher = Cipher.getInstance(DES);
        DESKeySpec ds = new DESKeySpec(key);
        SecureRandom sr = new SecureRandom();
        SecretKeyFactory skfactory = SecretKeyFactory.getInstance(DES);
        SecretKey skey = skfactory.generateSecret(ds);
        cipher.init(Cipher.DECRYPT_MODE, skey, sr);
        return cipher.doFinal(data);
    }

    // 解密
    public static String decrypt(String data, String key) throws Exception {
        return new String(decrypt(hex2byte(data.getBytes()), key.getBytes()));
    }

    private static String byte2hex( byte [] b) {
        StringBuilder hs = new StringBuilder();
        String stmp;
        for ( int n = 0 ; b != null && n < b.length; n++) {
            stmp = Integer.toHexString(b[n] & 0XFF );
            if (stmp.length() == 1 )
                hs.append( '0' );
            hs.append(stmp);
        }
        return hs.toString().toUpperCase();
    }

    private static byte [] hex2byte( byte [] b) {
        if ((b.length % 2 ) != 0 )
            throw new IllegalArgumentException();
        byte [] b2 = new byte [b.length / 2 ];
        for ( int n = 0 ; n < b.length; n += 2 ) {
            String item = new String(b, n, 2 );
            b2[n / 2 ] = ( byte ) Integer.parseInt(item, 16 );
        }
        return b2;
    }
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