很多時候要對秘要進行持久化加密，此時的加密采用md5。采用對稱加密的時候就采用DES方法了
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import java.io.IOException; import java.security.MessageDigest; import java.security.SecureRandom; import javax.crypto.Cipher; import javax.crypto.SecretKey; import javax.crypto.SecretKeyFactory; import javax.crypto.spec.DESKeySpec; import sun.misc.BASEDecoder; import sun.misc.BASEEncoder; /** * 密匙工具類(包含des加密與md加密) * @author mingge * */ public class KeysUtil { private final static String DES = "DES"; private final static String MD = "MD"; private final static String KEY="opeddsaeaddadbcabf"; /** * MD加密算法 * @param data * @return */ public static String mdEncrypt(String data) { String resultString = null; try { resultString = new String(data); MessageDigest md = MessageDigest.getInstance(MD); resultString =bytehexString(md.digest(resultString.getBytes())); } catch (Exception ex) { } return resultString; } private static String bytehexString(byte[] bytes) { StringBuffer bf = new StringBuffer(bytes.length * ); for (int i = ; i < bytes.length; i++) { if ((bytes[i] & xff) < x) { bf.append("T"); } bf.append(Long.toString(bytes[i] & xff, )); } return bf.toString(); } /** * Description 根據鍵值進行加密 * @param data * @param key 加密鍵byte數組 * @return * @throws Exception */ public static String desEncrypt(String data, String key) throws Exception { if (key==null) { key=KEY; } byte[] bt = encrypt(data.getBytes(), key.getBytes()); String strs = new BASEEncoder().encode(bt); return strs; } /** * Description 根據鍵值進行解密 * @param data * @param key 加密鍵byte數組 * @return * @throws IOException * @throws Exception */ public static String desDecrypt(String data, String key) throws IOException, Exception { if (data == null){ return null; } if (key==null) { key=KEY; } BASEDecoder decoder = new BASEDecoder(); byte[] buf = decoder.decodeBuffer(data); byte[] bt = decrypt(buf,key.getBytes()); return new String(bt); } /** * Description 根據鍵值進行加密 * @param data * @param key 加密鍵byte數組 * @return * @throws Exception */ private static byte[] encrypt(byte[] data, byte[] key) throws Exception { // 生成一個可信任的隨機數源 SecureRandom sr = new SecureRandom(); // 從原始密鑰數據創建DESKeySpec對象 DESKeySpec dks = new DESKeySpec(key); // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher對象實際完成加密操作 Cipher cipher = Cipher.getInstance(DES); // 用密鑰初始化Cipher對象 cipher.init(Cipher.ENCRYPT_MODE, securekey, sr); return cipher.doFinal(data); } /** * Description 根據鍵值進行解密 * @param data * @param key 加密鍵byte數組 * @return * @throws Exception */ private static byte[] decrypt(byte[] data, byte[] key) throws Exception { // 生成一個可信任的隨機數源 SecureRandom sr = new SecureRandom(); // 從原始密鑰數據創建DESKeySpec對象 DESKeySpec dks = new DESKeySpec(key); // 創建一個密鑰工廠，然后用它把DESKeySpec轉換成SecretKey對象 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES); SecretKey securekey = keyFactory.generateSecret(dks); // Cipher對象實際完成解密操作 Cipher cipher = Cipher.getInstance(DES); // 用密鑰初始化Cipher對象 cipher.init(Cipher.DECRYPT_MODE, securekey, sr); return cipher.doFinal(data); } } |
下面在給大家介紹一段代碼關于Java實現MD5加密解密類
Java實現MD5加密以及解密類，附帶測試類，具體見代碼。
MD5加密解密類——MyMD5Util,代碼如下：
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package com.zyg.security.md5; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.security.SecureRandom; import java.util.Arrays; public class MyMD5Util { private static final String HEX_NUMS_STR="0123456789ABCDEF"; private static final Integer SALT_LENGTH = 12; /** * 將16進制字符串轉換成字節數組 * @param hex * @return */ public static byte[] hexStringToByte(String hex) { int len = (hex.length() / 2); byte[] result = new byte[len]; char[] hexChars = hex.toCharArray(); for (int i = 0; i < len; i++) { int pos = i * 2; result[i] = (byte) (HEX_NUMS_STR.indexOf(hexChars[pos]) << 4 | HEX_NUMS_STR.indexOf(hexChars[pos + 1])); } return result; } /** * 將指定byte數組轉換成16進制字符串 * @param b * @return */ public static String byteToHexString(byte[] b) { StringBuffer hexString = new StringBuffer(); for (int i = 0; i < b.length; i++) { String hex = Integer.toHexString(b[i] & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } hexString.append(hex.toUpperCase()); } return hexString.toString(); } /** * 驗證口令是否合法 * @param password * @param passwordInDb * @return * @throws NoSuchAlgorithmException * @throws UnsupportedEncodingException */ public static boolean validPassword(String password, String passwordInDb) throws NoSuchAlgorithmException, UnsupportedEncodingException { //將16進制字符串格式口令轉換成字節數組 byte[] pwdInDb = hexStringToByte(passwordInDb); //聲明鹽變量 byte[] salt = new byte[SALT_LENGTH]; //將鹽從數據庫中保存的口令字節數組中提取出來 System.arraycopy(pwdInDb, 0, salt, 0, SALT_LENGTH); //創建消息摘要對象 MessageDigest md = MessageDigest.getInstance("MD5"); //將鹽數據傳入消息摘要對象 md.update(salt); //將口令的數據傳給消息摘要對象 md.update(password.getBytes("UTF-8")); //生成輸入口令的消息摘要 byte[] digest = md.digest(); //聲明一個保存數據庫中口令消息摘要的變量 byte[] digestInDb = new byte[pwdInDb.length - SALT_LENGTH]; //取得數據庫中口令的消息摘要 System.arraycopy(pwdInDb, SALT_LENGTH, digestInDb, 0, digestInDb.length); //比較根據輸入口令生成的消息摘要和數據庫中消息摘要是否相同 if (Arrays.equals(digest, digestInDb)) { //口令正確返回口令匹配消息 return true; } else { //口令不正確返回口令不匹配消息 return false; } } /** * 獲得加密后的16進制形式口令 * @param password * @return * @throws NoSuchAlgorithmException * @throws UnsupportedEncodingException */ public static String getEncryptedPwd(String password) throws NoSuchAlgorithmException, UnsupportedEncodingException { //聲明加密后的口令數組變量 byte[] pwd = null; //隨機數生成器 SecureRandom random = new SecureRandom(); //聲明鹽數組變量 byte[] salt = new byte[SALT_LENGTH]; //將隨機數放入鹽變量中 random.nextBytes(salt); //聲明消息摘要對象 MessageDigest md = null; //創建消息摘要 md = MessageDigest.getInstance("MD5"); //將鹽數據傳入消息摘要對象 md.update(salt); //將口令的數據傳給消息摘要對象 md.update(password.getBytes("UTF-8")); //獲得消息摘要的字節數組 byte[] digest = md.digest(); //因為要在口令的字節數組中存放鹽，所以加上鹽的字節長度 pwd = new byte[digest.length + SALT_LENGTH]; //將鹽的字節拷貝到生成的加密口令字節數組的前12個字節，以便在驗證口令時取出鹽 System.arraycopy(salt, 0, pwd, 0, SALT_LENGTH); //將消息摘要拷貝到加密口令字節數組從第13個字節開始的字節 System.arraycopy(digest, 0, pwd, SALT_LENGTH, digest.length); //將字節數組格式加密后的口令轉化為16進制字符串格式的口令 return byteToHexString(pwd); } } |
測試類——Client,代碼如下：
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package com.zyg.security.md5; import java.io.UnsupportedEncodingException; import java.security.NoSuchAlgorithmException; import java.util.HashMap; import java.util.Map; public class Client { private static Map users = new HashMap(); public static void main(String[] args){ String userName = "zyg"; String password = "123"; registerUser(userName,password); userName = "changong"; password = "456"; registerUser(userName,password); String loginUserId = "zyg"; String pwd = "1232"; try { if(loginValid(loginUserId,pwd)){ System.out.println("歡迎登陸！！！"); }else{ System.out.println("口令錯誤，請重新輸入！！！"); } } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 注冊用戶 * * @param userName * @param password */ public static void registerUser(String userName,String password){ String encryptedPwd = null; try { encryptedPwd = MyMD5Util.getEncryptedPwd(password); users.put(userName, encryptedPwd); } catch (NoSuchAlgorithmException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (UnsupportedEncodingException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * 驗證登陸 * * @param userName * @param password * @return * @throws UnsupportedEncodingException * @throws NoSuchAlgorithmException */ public static boolean loginValid(String userName,String password) throws NoSuchAlgorithmException, UnsupportedEncodingException{ String pwdInDb = (String)users.get(userName); if(null!=pwdInDb){ // 該用戶存在 return MyMD5Util.validPassword(password, pwdInDb); }else{ System.out.println("不存在該用戶！！！"); return false; } } } |
