可变MD5加密(Java实现)
可变在这里含义很简单,就是最终的加密结果是可变的,而非必需按标准MD5加密实现。Java类库security中的MessageDigest类就提供了MD5加密的支持,实现起来非常方便。为了实现更多效果,我们可以如下设计MD5工具类。
- package **.**.util;
- import java.security.MessageDigest;
- /**
- * 标准MD5加密方法,使用java类库的security包的MessageDigest类处理
- * @author Sarin
- */
- public class MD5 {
- /**
- * 获得MD5加密密码的方法
- */
- public static String getMD5ofStr(String origString) {
- String origMD5 = null;
- try {
- MessageDigest md5 = MessageDigest.getInstance("MD5");
- byte[] result = md5.digest(origString.getBytes());
- origMD5 = byteArray2HexStr(result);
- } catch (Exception e) {
- e.printStackTrace();
- }
- return origMD5;
- }
- /**
- * 处理字节数组得到MD5密码的方法
- */
- private static String byteArray2HexStr(byte[] bs) {
- StringBuffer sb = new StringBuffer();
- for (byte b : bs) {
- sb.append(byte2HexStr(b));
- }
- return sb.toString();
- }
- /**
- * 字节标准移位转十六进制方法
- */
- private static String byte2HexStr(byte b) {
- String hexStr = null;
- int n = b;
- if (n < 0) {
- //若需要自定义加密,请修改这个移位算法即可
- n = b & 0x7F + 128;
- }
- hexStr = Integer.toHexString(n / 16) + Integer.toHexString(n % 16);
- return hexStr.toUpperCase();
- }
- /**
- * 提供一个MD5多次加密方法
- */
- public static String getMD5ofStr(String origString, int times) {
- String md5 = getMD5ofStr(origString);
- for (int i = 0; i < times - 1; i++) {
- md5 = getMD5ofStr(md5);
- }
- return getMD5ofStr(md5);
- }
- /**
- * 密码验证方法
- */
- public static boolean verifyPassword(String inputStr, String MD5Code) {
- return getMD5ofStr(inputStr).equals(MD5Code);
- }
- /**
- * 重载一个多次加密时的密码验证方法
- */
- public static boolean verifyPassword(String inputStr, String MD5Code, int times) {
- return getMD5ofStr(inputStr, times).equals(MD5Code);
- }
- /**
- * 提供一个测试的主函数
- */
- public static void main(String[] args) {
- System.out.println("123:" + getMD5ofStr("123"));
- System.out.println("123456789:" + getMD5ofStr("123456789"));
- System.out.println("sarin:" + getMD5ofStr("sarin"));
- System.out.println("123:" + getMD5ofStr("123", 4));
- }
- }
可以看出实现的过程非常简单,因为由java类库提供了处理支持。但是要清楚的是这种方式产生的密码不是标准的MD5码,它需要进行移位处理才能得到标准 MD5码。这个程序的关键之处也在这了,怎么可变?调整移位算法不就可变了么!不进行移位,也能够得到32位的密码,这就不是标准加密了,只要加密和验证 过程使用相同的算法就可以了。
MD5加密还是很安全的,像CMD5那些穷举破解的只是针对标准MD5加密的结果进行的,如果自定义移位算法后,它还有效么?可以说是无解的了,所以MD5非常安全可靠。
为了更可变,还提供了多次加密的方法,可以在MD5基础之上继续MD5,就是对32位的第一次加密结果再MD5,恩,这样去破解?没有任何意义。
这样在MIS系统中使用,安全可靠,欢迎交流,希望对使用者有用。
我们最后看看由MD5加密算法实现的类,那是非常庞大的。
- import java.lang.reflect.*;
- /**
- * **********************************************
- * md5 类实现了RSA Data Security, Inc.在提交给IETF
- * 的RFC1321中的MD5 message-digest 算法。
- * ***********************************************
- */
- public class MD5 {
- /* 下面这些S11-S44实际上是一个4*4的矩阵,在原始的C实现中是用#define 实现的,
- 这里把它们实现成为static final是表示了只读,切能在同一个进程空间内的多个
- Instance间共享*/
- static final int S11 = 7;
- static final int S12 = 12;
- static final int S13 = 17;
- static final int S14 = 22;
- static final int S21 = 5;
- static final int S22 = 9;
- static final int S23 = 14;
- static final int S24 = 20;
- static final int S31 = 4;
- static final int S32 = 11;
- static final int S33 = 16;
- static final int S34 = 23;
- static final int S41 = 6;
- static final int S42 = 10;
- static final int S43 = 15;
- static final int S44 = 21;
- static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
- 0 };
- /* 下面的三个成员是MD5计算过程中用到的3个核心数据,在原始的C实现中
- 被定义到MD5_CTX结构中
- */
- private long[] state = new long[4]; // state (ABCD)
- private long[] count = new long[2]; // number of bits, modulo 2^64 (lsb first)
- private byte[] buffer = new byte[64]; // input buffer
- /* digestHexStr是MD5的唯一一个公共成员,是最新一次计算结果的
- 16进制ASCII表示.
- */
- public String digestHexStr;
- /* digest,是最新一次计算结果的2进制内部表示,表示128bit的MD5值.
- */
- private byte[] digest = new byte[16];
- /*
- getMD5ofStr是类MD5最主要的公共方法,入口参数是你想要进行MD5变换的字符串
- 返回的是变换完的结果,这个结果是从公共成员digestHexStr取得的.
- */
- public String getMD5ofStr(String inbuf) {
- md5Init();
- md5Update(inbuf.getBytes(), inbuf.length());
- md5Final();
- digestHexStr = "";
- for (int i = 0; i < 16; i++) {
- digestHexStr += byteHEX(digest[i]);
- }
- return digestHexStr;
- }
- // 这是MD5这个类的标准构造函数,JavaBean要求有一个public的并且没有参数的构造函数
- public MD5() {
- md5Init();
- return;
- }
- /* md5Init是一个初始化函数,初始化核心变量,装入标准的幻数 */
- private void md5Init() {
- count[0] = 0L;
- count[1] = 0L;
- ///* Load magic initialization constants.
- state[0] = 0x67452301L;
- state[1] = 0xefcdab89L;
- state[2] = 0x98badcfeL;
- state[3] = 0x10325476L;
- return;
- }
- /* F, G, H ,I 是4个基本的MD5函数,在原始的MD5的C实现中,由于它们是
- 简单的位运算,可能出于效率的考虑把它们实现成了宏,在java中,我们把它们
- 实现成了private方法,名字保持了原来C中的。 */
- private long F(long x, long y, long z) {
- return (x & y) | ((~x) & z);
- }
- private long G(long x, long y, long z) {
- return (x & z) | (y & (~z));
- }
- private long H(long x, long y, long z) {
- return x ^ y ^ z;
- }
- private long I(long x, long y, long z) {
- return y ^ (x | (~z));
- }
- /*
- FF,GG,HH和II将调用F,G,H,I进行近一步变换
- FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
- Rotation is separate from addition to prevent recomputation.
- */
- private long FF(long a, long b, long c, long d, long x, long s, long ac) {
- a += F(b, c, d) + x + ac;
- a = ((int) a << s) | ((int) a >>> (32 - s));
- a += b;
- return a;
- }
- private long GG(long a, long b, long c, long d, long x, long s, long ac) {
- a += G(b, c, d) + x + ac;
- a = ((int) a << s) | ((int) a >>> (32 - s));
- a += b;
- return a;
- }
- private long HH(long a, long b, long c, long d, long x, long s, long ac) {
- a += H(b, c, d) + x + ac;
- a = ((int) a << s) | ((int) a >>> (32 - s));
- a += b;
- return a;
- }
- private long II(long a, long b, long c, long d, long x, long s, long ac) {
- a += I(b, c, d) + x + ac;
- a = ((int) a << s) | ((int) a >>> (32 - s));
- a += b;
- return a;
- }
- /*
- md5Update是MD5的主计算过程,inbuf是要变换的字节串,inputlen是长度,这个
- 函数由getMD5ofStr调用,调用之前需要调用md5init,因此把它设计成private的
- */
- private void md5Update(byte[] inbuf, int inputLen) {
- int i, index, partLen;
- byte[] block = new byte[64];
- index = (int) (count[0] >>> 3) & 0x3F;
- // /* Update number of bits */
- if ((count[0] += (inputLen << 3)) < (inputLen << 3))
- count[1]++;
- count[1] += (inputLen >>> 29);
- partLen = 64 - index;
- // Transform as many times as possible.
- if (inputLen >= partLen) {
- md5Memcpy(buffer, inbuf, index, 0, partLen);
- md5Transform(buffer);
- for (i = partLen; i + 63 < inputLen; i += 64) {
- md5Memcpy(block, inbuf, 0, i, 64);
- md5Transform(block);
- }
- index = 0;
- } else
- i = 0;
- ///* Buffer remaining input */
- md5Memcpy(buffer, inbuf, index, i, inputLen - i);
- }
- /*
- md5Final整理和填写输出结果
- */
- private void md5Final() {
- byte[] bits = new byte[8];
- int index, padLen;
- ///* Save number of bits */
- Encode(bits, count, 8);
- ///* Pad out to 56 mod 64.
- index = (int) (count[0] >>> 3) & 0x3f;
- padLen = (index < 56) ? (56 - index) : (120 - index);
- md5Update(PADDING, padLen);
- ///* Append length (before padding) */
- md5Update(bits, 8);
- ///* Store state in digest */
- Encode(digest, state, 16);
- }
- /* md5Memcpy是一个内部使用的byte数组的块拷贝函数,从input的inpos开始把len长度的
- 字节拷贝到output的outpos位置开始
- */
- private void md5Memcpy(byte[] output, byte[] input, int outpos, int inpos, int len) {
- int i;
- for (i = 0; i < len; i++)
- output[outpos + i] = input[inpos + i];
- }
- /*
- md5Transform是MD5核心变换程序,有md5Update调用,block是分块的原始字节
- */
- private void md5Transform(byte block[]) {
- long a = state[0], b = state[1], c = state[2], d = state[3];
- long[] x = new long[16];
- Decode(x, block, 64);
- /* Round 1 */
- a = FF(a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */
- d = FF(d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */
- c = FF(c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */
- b = FF(b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */
- a = FF(a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */
- d = FF(d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */
- c = FF(c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */
- b = FF(b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */
- a = FF(a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */
- d = FF(d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */
- c = FF(c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */
- b = FF(b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */
- a = FF(a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */
- d = FF(d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */
- c = FF(c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */
- b = FF(b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */
- /* Round 2 */
- a = GG(a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */
- d = GG(d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */
- c = GG(c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */
- b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */
- a = GG(a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */
- d = GG(d, a, b, c, x[10], S22, 0x2441453L); /* 22 */
- c = GG(c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */
- b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */
- a = GG(a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */
- d = GG(d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */
- c = GG(c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */
- b = GG(b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */
- a = GG(a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */
- d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */
- c = GG(c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */
- b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */
- /* Round 3 */
- a = HH(a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */
- d = HH(d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */
- c = HH(c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */
- b = HH(b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */
- a = HH(a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */
- d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */
- c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */
- b = HH(b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */
- a = HH(a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */
- d = HH(d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */
- c = HH(c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */
- b = HH(b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */
- a = HH(a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */
- d = HH(d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */
- c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */
- b = HH(b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */
- /* Round 4 */
- a = II(a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */
- d = II(d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */
- c = II(c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */
- b = II(b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */
- a = II(a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */
- d = II(d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */
- c = II(c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */
- b = II(b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */
- a = II(a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */
- d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */
- c = II(c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */
- b = II(b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */
- a = II(a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */
- d = II(d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */
- c = II(c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */
- b = II(b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */
- state[0] += a;
- state[1] += b;
- state[2] += c;
- state[3] += d;
- }
- /*Encode把long数组按顺序拆成byte数组,因为java的long类型是64bit的,
- 只拆低32bit,以适应原始C实现的用途
- */
- private void Encode(byte[] output, long[] input, int len) {
- int i, j;
- for (i = 0, j = 0; j < len; i++, j += 4) {
- output[j] = (byte) (input[i] & 0xffL);
- output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL);
- output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL);
- output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL);
- }
- }
- /*Decode把byte数组按顺序合成成long数组,因为java的long类型是64bit的,
- 只合成低32bit,高32bit清零,以适应原始C实现的用途
- */
- private void Decode(long[] output, byte[] input, int len) {
- int i, j;
- for (i = 0, j = 0; j < len; i++, j += 4)
- output[i] = b2iu(input[j]) | (b2iu(input[j + 1]) << 8) | (b2iu(input[j + 2]) << 16)
- | (b2iu(input[j + 3]) << 24);
- return;
- }
- /*
- b2iu是我写的一个把byte按照不考虑正负号的原则的"升位"程序,因为java没有unsigned运算
- */
- public static long b2iu(byte b) {
- return b < 0 ? b & 0x7F + 128 : b;
- }
- /*byteHEX(),用来把一个byte类型的数转换成十六进制的ASCII表示,
- 因为java中的byte的toString无法实现这一点,我们又没有C语言中的
- sprintf(outbuf,"%02X",ib)
- */
- public static String byteHEX(byte ib) {
- char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
- char[] ob = new char[2];
- ob[0] = Digit[(ib >>> 4) & 0X0F];
- ob[1] = Digit[ib & 0X0F];
- String s = new String(ob);
- return s;
- }
- public static void main(String args[]) {
- MD5 m = new MD5();
- if (Array.getLength(args) == 0) { //如果没有参数,执行标准的Test Suite
- System.out.println("MD5 Test suite:");
- System.out.println("MD5(\"\"):" + m.getMD5ofStr(""));
- System.out.println("MD5(\"a\"):" + m.getMD5ofStr("a"));
- System.out.println("MD5(\"abc\"):" + m.getMD5ofStr("abc"));
- System.out.println("MD5(\"11\"):" + m.getMD5ofStr("11"));
- System.out.println("MD5(\"123\"):" + m.getMD5ofStr("123"));
- System.out.println("MD5(\"message digest\"):" + m.getMD5ofStr("message digest"));
- System.out.println("MD5(\"abcdefghijklmnopqrstuvwxyz\"):" + m.getMD5ofStr("abcdefghijklmnopqrstuvwxyz"));
- System.out.println("MD5(\"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\"):"
- + m.getMD5ofStr("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"));
- } else
- System.out.println("MD5(" + args[0] + ")=" + m.getMD5ofStr(args[0]));
- }
- }