java实现DES加密与解密，md5加密

              1
            import
             java.io.IOException;

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            import
             java.security.MessageDigest;

              3
            import
             java.security.SecureRandom;

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              5
            import
             javax.crypto.Cipher;

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            import
             javax.crypto.SecretKey;

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            import
             javax.crypto.SecretKeyFactory;

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            import
             javax.crypto.spec.DESKeySpec;

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             10
            import
             sun.misc.BASE64Decoder;

             11
            import
             sun.misc.BASE64Encoder;

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             13
            /**
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             * 密匙工具类(包含des加密与md5加密)

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             * 
            @author
             mingge

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             *

             17
            */
             18
            public
            class
             KeysUtil {

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             20
            private
            final
            static String DES = "DES";
 21 22privatefinalstatic String MD5 = "MD5";
 23 24privatefinalstatic String KEY="opeddsaead323353484591dadbc382a18340bf83414536";
 25 26/** 27         * MD5加密算法
 28         * @param data
 29         * @return 30*/ 31publicstatic String md5Encrypt(String data) {
 32             String resultString = null;
 33try {
 34                 resultString = new String(data);
 35                 MessageDigest md = MessageDigest.getInstance(MD5);
 36                 resultString =byte2hexString(md.digest(resultString.getBytes()));
 37             } catch (Exception ex) {
 38            }
 39return resultString;
 40        }
 41 42 43privatestatic String byte2hexString(byte[] bytes) {
 44             StringBuffer bf = new StringBuffer(bytes.length * 2);
 45for (int i = 0; i < bytes.length; i++) {
 46if ((bytes[i] & 0xff) < 0x10) {
 47                     bf.append("T0");
 48                }
 49                 bf.append(Long.toString(bytes[i] & 0xff, 16));
 50            }
 51return bf.toString();
 52        }
 53 54/** 55         * Description 根据键值进行加密
 56         * @param data 
 57         * @param key  加密键byte数组
 58         * @return 59         * @throws Exception
 60*/ 61publicstatic String desEncrypt(String data, String key) throws Exception {
 62if (key==null) {
 63                 key=KEY;
 64            }
 65byte[] bt = encrypt(data.getBytes(), key.getBytes());
 66             String strs = new BASE64Encoder().encode(bt);
 67return strs;
 68        }
 69 70/** 71         * Description 根据键值进行解密
 72         * @param data
 73         * @param key  加密键byte数组
 74         * @return 75         * @throws IOException
 76         * @throws Exception
 77*/ 78publicstatic String desDecrypt(String data, String key) throws IOException,
 79                Exception {
 80if (data == null){
 81returnnull;
 82            }
 83if (key==null) {
 84                 key=KEY;
 85            }
 86             BASE64Decoder decoder = new BASE64Decoder();
 87byte[] buf = decoder.decodeBuffer(data);
 88byte[] bt = decrypt(buf,key.getBytes());
 89returnnew String(bt);
 90        }
 91 92/** 93         * Description 根据键值进行加密
 94         * @param data
 95         * @param key  加密键byte数组
 96         * @return 97         * @throws Exception
 98*/ 99privatestaticbyte[] encrypt(byte[] data, byte[] key) throws Exception {
100// 生成一个可信任的随机数源101             SecureRandom sr = new SecureRandom();
102// 从原始密钥数据创建DESKeySpec对象103             DESKeySpec dks = new DESKeySpec(key);
104// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象105             SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
106             SecretKey securekey = keyFactory.generateSecret(dks);
107// Cipher对象实际完成加密操作108             Cipher cipher = Cipher.getInstance(DES);
109// 用密钥初始化Cipher对象110            cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
111return cipher.doFinal(data);
112        }
113114115/**116         * Description 根据键值进行解密
117         * @param data
118         * @param key  加密键byte数组
119         * @return120         * @throws Exception
121*/122privatestaticbyte[] decrypt(byte[] data, byte[] key) throws Exception {
123// 生成一个可信任的随机数源124             SecureRandom sr = new SecureRandom();
125// 从原始密钥数据创建DESKeySpec对象126             DESKeySpec dks = new DESKeySpec(key);
127// 创建一个密钥工厂，然后用它把DESKeySpec转换成SecretKey对象128             SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
129             SecretKey securekey = keyFactory.generateSecret(dks);
130// Cipher对象实际完成解密操作131             Cipher cipher = Cipher.getInstance(DES);
132// 用密钥初始化Cipher对象133            cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
134return cipher.doFinal(data);
135        }
136 }