淺析Java 常用的 4 種加密方式（MD5+Base64+SHA+BCrypt）

public class MD5Utils {
 private static final String hexDigIts[] = {"0","1","2","3","4","5","6","7","8","9","a","b","c","d","e","f"};
 /**
 * MD5加密
 * @param origin 字符
 * @param charsetname 編碼
 * @return
 */
 public static String MD5Encode(String origin, String charsetname){
 String resultString = null;
 try{
  resultString = new String(origin);
  MessageDigest md = MessageDigest.getInstance("MD5");
  if(null == charsetname || "".equals(charsetname)){
  resultString = byteArrayToHexString(md.digest(resultString.getBytes()));
  }else{
  resultString = byteArrayToHexString(md.digest(resultString.getBytes(charsetname)));
  }
 }catch (Exception e){
 }
 return resultString;
 }
 public static String byteArrayToHexString(byte b[]){
 StringBuffer resultSb = new StringBuffer();
 for(int i = 0; i < b.length; i++){
  resultSb.append(byteToHexString(b[i]));
 }
 return resultSb.toString();
 }
 public static String byteToHexString(byte b){
 int n = b;
 if(n < 0){
  n += 256;
 }
 int d1 = n / 16;
 int d2 = n % 16;
 return hexDigIts[d1] + hexDigIts[d2];
 }
}

public class Base64Util {
 // 字符串編碼
 private static final String UTF_8 = "UTF-8";
 /**
 * 加密字符串
 * @param inputData
 * @return
 */
 public static String decodeData(String inputData) {
 try {
  if (null == inputData) {
  return null;
  }
  return new String(Base64.decodeBase64(inputData.getBytes(UTF_8)), UTF_8);
 } catch (UnsupportedEncodingException e) {
 }
 return null;
 }
 /**
 * 解密加密后的字符串
 * @param inputData
 * @return
 */
 public static String encodeData(String inputData) {
 try {
  if (null == inputData) {
  return null;
  }
  return new String(Base64.encodeBase64(inputData.getBytes(UTF_8)), UTF_8);
 } catch (UnsupportedEncodingException e) {
 }
 return null;
 }
 public static void main(String[] args) {
 System.out.println(Base64Util.encodeData("我是中文"));
 String enStr = Base64Util.encodeData("我是中文");
 System.out.println(Base64Util.decodeData(enStr));
 }
}

public class BcryptCipher {
 // generate salt seed
 private static final int SALT_SEED = 12;
 // the head fo salt
 private static final String SALT_STARTSWITH = "$2a$12";
 
 public static final String SALT_KEY = "salt";
 
 public static final String CIPHER_KEY = "cipher";
 
 /**
 * Bcrypt encryption algorithm method
 * @param encryptSource
 * need to encrypt the string
 * @return Map , two values in Map , salt and cipher
 */
 public static Map<String, String> Bcrypt(final String encryptSource) {
 String salt = BCrypt.gensalt(SALT_SEED);
 Map<String, String> bcryptResult = Bcrypt(salt, encryptSource);
 return bcryptResult;
 }
 /**
 *
 * @param salt encrypt salt, Must conform to the rules
 * @param encryptSource
 * @return
 */
 public static Map<String, String> Bcrypt(final String salt, final String encryptSource) {
 if (StringUtils.isBlank(encryptSource)) {
 throw new RuntimeException("Bcrypt encrypt input params can not be empty");
 }
 
 if (StringUtils.isBlank(salt) || salt.length() != 29) {
 throw new RuntimeException("Salt can't be empty and length must be to 29");
 }
 if (!salt.startsWith(SALT_STARTSWITH)) {
 throw new RuntimeException("Invalid salt version, salt version is $2a$12");
 }
 
 String cipher = BCrypt.hashpw(encryptSource, salt);
 Map<String, String> bcryptResult = new HashMap<String, String>();
 bcryptResult.put(SALT_KEY, salt);
 bcryptResult.put(CIPHER_KEY, cipher);
 return bcryptResult;
 }
 
}

/**
 * MD5加密
 */
public class MD5Test {
 public static void main(String[] args) {
 String string = "你好 世界";
 String byteArrayToHexString = MD5Utils.byteArrayToHexString(string.getBytes());
 System.out.println(byteArrayToHexString);//e68891e698afe4b880e58fa5e8af9d
 
 }
}

/**
 * base64加密
 */
public class Bast64Tester {
 
 public static void main(String[] args) {
 String string = "你好 世界";
 String encodeData = Base64Util.encodeData(string); //加密
 String decodeData = Base64Util.decodeData(encodeData); //解密
 System.out.println(encodeData);//5oiR5piv5LiA5Liq5a2X56ym5Liy
 System.out.println(decodeData);//你好 世界
 
 }
}

/**
 * SHA加密
 */
public class ShaTest {
 
 public static void main(String[] args) {
 String string = "你好 世界";
 
 String sha256Crypt = Sha2Crypt.sha256Crypt(string.getBytes());
 System.out.println(sha256Crypt);//$5$AFoQTeyt$TiqmobvcQXjXaAQMYosAAO4KI8LfigZMGHzq.Dlp4NC
 
 }
}

/**
 * BCrypt加密
 */
public class BCryptTest {
 
 public static void main(String[] args) {
 
 String string = "你好世界";
 Map<String, String> bcrypt = BcryptCipher.Bcrypt(string);
 System.out.println(bcrypt.keySet()); //[cipher, salt]
 
 System.out.println(bcrypt.get("cipher")); //$2a$12$ylb92Z84gqlrSfzIztlCV.dK0xNbw.pOv3UwXXA76llOsNRTJsE/.
 System.out.println(bcrypt.get("salt")); //$2a$12$ylb92Z84gqlrSfzIztlCV.
 
 Map<String, String> bcrypt2 = BcryptCipher.Bcrypt(bcrypt.get("salt"),string);
 System.out.println(bcrypt2.get("SALT_KEY")); //null
 System.out.println(bcrypt2.get("CIPHER_KEY")); //null
 }
}