简单MD5 类
1 import java.security.*; 2 import java.security.spec.*; 3 4 class MD5_test { 5 public final static String MD5(String s) { 6 char hexDigits[] = { '0' , '1' , '2' , '3' , '4' , '5' , '6' , '7' , '8' , '9' , 7 'a' , 'b' , 'c' , 'd' , 'e' , 'f' }; 8 try { 9 byte [] strTemp = s.getBytes(); 10 MessageDigest mdTemp = MessageDigest.getInstance("MD5" ); 11 mdTemp.update(strTemp); 12 byte [] md = mdTemp.digest(); 13 int j = md.length; 14 char str[] = new char [j * 2 ]; 15 int k = 0 ; 16 for ( int i = 0 ; i < j; i++) { 17 byte byte0 = md[i]; 18 str[k++] = hexDigits[byte0 >>> 4 & 0xf ]; 19 str[k++] = hexDigits[byte0 & 0xf ]; 20 } 21 return new String(str); 22 } catch (Exception e) { 23 return null ; 24 } 25 } 26 27 public static void main(String[] args) { 28 // MD5_Test aa = new MD5_Test(); 29 System.out.print(MD5_test.MD5("b" )); 30 } 31 }
加密--解密 MD5类
import java.security.MessageDigest; public class MD5andKL { // MD5加码。32位 public static String MD5(String inStr) { MessageDigest md5 = null; try { md5 = MessageDigest.getInstance("MD5"); } catch (Exception e) { System.out.println(e.toString()); e.printStackTrace(); return ""; } char[] charArray = inStr.toCharArray(); byte[] byteArray = new byte[charArray.length]; for (int i = 0; i < charArray.length; i++) byteArray[i] = (byte) charArray[i]; byte[] md5Bytes = md5.digest(byteArray); StringBuffer hexValue = new StringBuffer(); for (int i = 0; i < md5Bytes.length; i++) { int val = ((int) md5Bytes[i]) & 0xff; if (val < 16) hexValue.append("0"); hexValue.append(Integer.toHexString(val)); } return hexValue.toString(); } // 可逆的加密算法 public static String KL(String inStr) { // String s = new String(inStr); char[] a = inStr.toCharArray(); for (int i = 0; i < a.length; i++) { a[i] = (char) (a[i] ^ 't'); } String s = new String(a); return s; } // 加密后解密 public static String JM(String inStr) { char[] a = inStr.toCharArray(); for (int i = 0; i < a.length; i++) { a[i] = (char) (a[i] ^ 't'); } String k = new String(a); return k; } // 测试主函数 public static void main(String args[]) { String s = new String("a"); System.out.println("原始:" + s); System.out.println("MD5后:" + MD5(s)); System.out.println("MD5后再加密:" + KL(MD5(s))); System.out.println("解密为MD5后的:" + JM(KL(MD5(s)))); } }