MD5加密~讓資料庫以密文顯示密碼

public class MD5Code {<br /> /*<br /> * 下面這些S11-S44實際上是一個4*4的矩陣，在原始的C實現中是用#define 實現的， 這裡把它們實現成為static<br /> * final是表示了唯讀，切能在同一個進程空間內的多個 Instance間共用<br /> */<br /> static final int S11 = 7;</p><p> static final int S12 = 12;</p><p> static final int S13 = 17;</p><p> static final int S14 = 22;</p><p> static final int S21 = 5;</p><p> static final int S22 = 9;</p><p> static final int S23 = 14;</p><p> static final int S24 = 20;</p><p> static final int S31 = 4;</p><p> static final int S32 = 11;</p><p> static final int S33 = 16;</p><p> static final int S34 = 23;</p><p> static final int S41 = 6;</p><p> static final int S42 = 10;</p><p> static final int S43 = 15;</p><p> static final int S44 = 21;</p><p> static final byte[] PADDING = { -128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,<br /> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,<br /> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,<br /> 0, 0, 0, 0, 0, 0, 0 };</p><p> /*<br /> * 下面的三個成員是MD5計算過程中用到的3個核心資料，在原始的C實現中 被定義到MD5_CTX結構中<br /> */<br /> private long[] state = new long[4];// state (ABCD)</p><p> private long[] count = new long[2];// number of bits, modulo 2^64 (lsb</p><p> // first)</p><p> private byte[] buffer = new byte[64]; // input buffer</p><p> /*<br /> * digestHexStr是MD5的唯一一個公用成員，是最新一次計算結果的 16進位ASCII表示.<br /> */</p><p> public String digestHexStr;</p><p> /*<br /> * digest,是最新一次計算結果的2進位內部表示，表示128bit的MD5值.<br /> */<br /> private byte[] digest = new byte[16];</p><p> /*<br /> * getMD5ofStr是類MD5最主要的公用方法，入口參數是你想要進行MD5變換的字串<br /> * 返回的是變換完的結果，這個結果是從公用成員digestHexStr取得的．<br /> */<br /> public String getMD5ofStr(String inbuf) {<br /> md5Init();<br /> md5Update(inbuf.getBytes(), inbuf.length());<br /> md5Final();<br /> digestHexStr = "";<br /> for (int i = 0; i < 16; i++) {<br /> digestHexStr += byteHEX(digest[i]);<br /> }<br /> return digestHexStr;<br /> }</p><p> // 這是MD5這個類的標準建構函式，JavaBean要求有一個public的並且沒有參數的建構函式<br /> public MD5Code() {<br /> md5Init();<br /> return;<br /> }</p><p> /* md5Init是一個初始化函數，初始化核心變數，裝入標準的幻數 */<br /> private void md5Init() {<br /> count[0] = 0L;<br /> count[1] = 0L;<br /> // /* Load magic initialization constants.<br /> state[0] = 0x67452301L;<br /> state[1] = 0xefcdab89L;<br /> state[2] = 0x98badcfeL;<br /> state[3] = 0x10325476L;<br /> return;<br /> }</p><p> /*<br /> * F, G, H ,I 是4個基本的MD5函數，在原始的MD5的C實現中，由於它們是<br /> * 簡單的位元運算，可能出於效率的考慮把它們實現成了宏，在java中，我們把它們 實現成了private方法，名字保持了原來C中的。<br /> */<br /> private long F(long x, long y, long z) {<br /> return (x & y) | ((~x) & z);<br /> }</p><p> private long G(long x, long y, long z) {<br /> return (x & z) | (y & (~z));<br /> }</p><p> private long H(long x, long y, long z) {<br /> return x ^ y ^ z;<br /> }</p><p> private long I(long x, long y, long z) {<br /> return y ^ (x | (~z));<br /> }</p><p> /*<br /> * FF,GG,HH和II將調用F,G,H,I進行近一步變換 FF, GG, HH, and II transformations for<br /> * rounds 1, 2, 3, and 4. Rotation is separate from addition to prevent<br /> * recomputation.<br /> */<br /> private long FF(long a, long b, long c, long d, long x, long s, long ac) {<br /> a += F(b, c, d) + x + ac;<br /> a = ((int) a << s) | ((int) a >>> (32 - s));<br /> a += b;<br /> return a;<br /> }</p><p> private long GG(long a, long b, long c, long d, long x, long s, long ac) {<br /> a += G(b, c, d) + x + ac;<br /> a = ((int) a << s) | ((int) a >>> (32 - s));<br /> a += b;<br /> return a;<br /> }</p><p> private long HH(long a, long b, long c, long d, long x, long s, long ac) {<br /> a += H(b, c, d) + x + ac;<br /> a = ((int) a << s) | ((int) a >>> (32 - s));<br /> a += b;<br /> return a;<br /> }</p><p> private long II(long a, long b, long c, long d, long x, long s, long ac) {<br /> a += I(b, c, d) + x + ac;<br /> a = ((int) a << s) | ((int) a >>> (32 - s));<br /> a += b;<br /> return a;<br /> }</p><p> /*<br /> * md5Update是MD5的主計算過程，inbuf是要變換的位元組串，inputlen是長度，這個<br /> * 函數由getMD5ofStr調用，調用之前需要調用md5init，因此把它設計成private的<br /> */<br /> private void md5Update(byte[] inbuf, int inputLen) {<br /> int i, index, partLen;<br /> byte[] block = new byte[64];<br /> index = (int) (count[0] >>> 3) & 0x3F;<br /> // /* Update number of bits */<br /> if ((count[0] += (inputLen << 3)) < (inputLen << 3))<br /> count[1]++;<br /> count[1] += (inputLen >>> 29);<br /> partLen = 64 - index;<br /> // Transform as many times as possible.<br /> if (inputLen >= partLen) {<br /> md5Memcpy(buffer, inbuf, index, 0, partLen);<br /> md5Transform(buffer);<br /> for (i = partLen; i + 63 < inputLen; i += 64) {<br /> md5Memcpy(block, inbuf, 0, i, 64);<br /> md5Transform(block);<br /> }<br /> index = 0;<br /> } else<br /> i = 0;<br /> // /* Buffer remaining input */<br /> md5Memcpy(buffer, inbuf, index, i, inputLen - i);<br /> }</p><p> /*<br /> * md5Final整理和填寫輸出結果<br /> */<br /> private void md5Final() {<br /> byte[] bits = new byte[8];<br /> int index, padLen;<br /> // /* Save number of bits */<br /> Encode(bits, count, 8);<br /> // /* Pad out to 56 mod 64.<br /> index = (int) (count[0] >>> 3) & 0x3f;<br /> padLen = (index < 56) ? (56 - index) : (120 - index);<br /> md5Update(PADDING, padLen);<br /> // /* Append length (before padding) */<br /> md5Update(bits, 8);<br /> // /* Store state in digest */<br /> Encode(digest, state, 16);<br /> }</p><p> /*<br /> * md5Memcpy是一個內部使用的byte數組的塊拷貝函數，從input的inpos開始把len長度的<br /> * 位元組拷貝到output的outpos位置開始<br /> */<br /> private void md5Memcpy(byte[] output, byte[] input, int outpos, int inpos,<br /> int len) {<br /> int i;<br /> for (i = 0; i < len; i++)<br /> output[outpos + i] = input[inpos + i];<br /> }</p><p> /*<br /> * md5Transform是MD5核心變換程式，有md5Update調用，block是分塊的原始位元組<br /> */<br /> private void md5Transform(byte block[]) {<br /> long a = state[0], b = state[1], c = state[2], d = state[3];<br /> long[] x = new long[16];<br /> Decode(x, block, 64);<br /> /* Round 1 */<br /> a = FF(a, b, c, d, x[0], S11, 0xd76aa478L); /* 1 */<br /> d = FF(d, a, b, c, x[1], S12, 0xe8c7b756L); /* 2 */<br /> c = FF(c, d, a, b, x[2], S13, 0x242070dbL); /* 3 */<br /> b = FF(b, c, d, a, x[3], S14, 0xc1bdceeeL); /* 4 */<br /> a = FF(a, b, c, d, x[4], S11, 0xf57c0fafL); /* 5 */<br /> d = FF(d, a, b, c, x[5], S12, 0x4787c62aL); /* 6 */<br /> c = FF(c, d, a, b, x[6], S13, 0xa8304613L); /* 7 */<br /> b = FF(b, c, d, a, x[7], S14, 0xfd469501L); /* 8 */<br /> a = FF(a, b, c, d, x[8], S11, 0x698098d8L); /* 9 */<br /> d = FF(d, a, b, c, x[9], S12, 0x8b44f7afL); /* 10 */<br /> c = FF(c, d, a, b, x[10], S13, 0xffff5bb1L); /* 11 */<br /> b = FF(b, c, d, a, x[11], S14, 0x895cd7beL); /* 12 */<br /> a = FF(a, b, c, d, x[12], S11, 0x6b901122L); /* 13 */<br /> d = FF(d, a, b, c, x[13], S12, 0xfd987193L); /* 14 */<br /> c = FF(c, d, a, b, x[14], S13, 0xa679438eL); /* 15 */<br /> b = FF(b, c, d, a, x[15], S14, 0x49b40821L); /* 16 */<br /> /* Round 2 */<br /> a = GG(a, b, c, d, x[1], S21, 0xf61e2562L); /* 17 */<br /> d = GG(d, a, b, c, x[6], S22, 0xc040b340L); /* 18 */<br /> c = GG(c, d, a, b, x[11], S23, 0x265e5a51L); /* 19 */<br /> b = GG(b, c, d, a, x[0], S24, 0xe9b6c7aaL); /* 20 */<br /> a = GG(a, b, c, d, x[5], S21, 0xd62f105dL); /* 21 */<br /> d = GG(d, a, b, c, x[10], S22, 0x2441453L); /* 22 */<br /> c = GG(c, d, a, b, x[15], S23, 0xd8a1e681L); /* 23 */<br /> b = GG(b, c, d, a, x[4], S24, 0xe7d3fbc8L); /* 24 */<br /> a = GG(a, b, c, d, x[9], S21, 0x21e1cde6L); /* 25 */<br /> d = GG(d, a, b, c, x[14], S22, 0xc33707d6L); /* 26 */<br /> c = GG(c, d, a, b, x[3], S23, 0xf4d50d87L); /* 27 */<br /> b = GG(b, c, d, a, x[8], S24, 0x455a14edL); /* 28 */<br /> a = GG(a, b, c, d, x[13], S21, 0xa9e3e905L); /* 29 */<br /> d = GG(d, a, b, c, x[2], S22, 0xfcefa3f8L); /* 30 */<br /> c = GG(c, d, a, b, x[7], S23, 0x676f02d9L); /* 31 */<br /> b = GG(b, c, d, a, x[12], S24, 0x8d2a4c8aL); /* 32 */<br /> /* Round 3 */<br /> a = HH(a, b, c, d, x[5], S31, 0xfffa3942L); /* 33 */<br /> d = HH(d, a, b, c, x[8], S32, 0x8771f681L); /* 34 */<br /> c = HH(c, d, a, b, x[11], S33, 0x6d9d6122L); /* 35 */<br /> b = HH(b, c, d, a, x[14], S34, 0xfde5380cL); /* 36 */<br /> a = HH(a, b, c, d, x[1], S31, 0xa4beea44L); /* 37 */<br /> d = HH(d, a, b, c, x[4], S32, 0x4bdecfa9L); /* 38 */<br /> c = HH(c, d, a, b, x[7], S33, 0xf6bb4b60L); /* 39 */<br /> b = HH(b, c, d, a, x[10], S34, 0xbebfbc70L); /* 40 */<br /> a = HH(a, b, c, d, x[13], S31, 0x289b7ec6L); /* 41 */<br /> d = HH(d, a, b, c, x[0], S32, 0xeaa127faL); /* 42 */<br /> c = HH(c, d, a, b, x[3], S33, 0xd4ef3085L); /* 43 */<br /> b = HH(b, c, d, a, x[6], S34, 0x4881d05L); /* 44 */<br /> a = HH(a, b, c, d, x[9], S31, 0xd9d4d039L); /* 45 */<br /> d = HH(d, a, b, c, x[12], S32, 0xe6db99e5L); /* 46 */<br /> c = HH(c, d, a, b, x[15], S33, 0x1fa27cf8L); /* 47 */<br /> b = HH(b, c, d, a, x[2], S34, 0xc4ac5665L); /* 48 */<br /> /* Round 4 */<br /> a = II(a, b, c, d, x[0], S41, 0xf4292244L); /* 49 */<br /> d = II(d, a, b, c, x[7], S42, 0x432aff97L); /* 50 */<br /> c = II(c, d, a, b, x[14], S43, 0xab9423a7L); /* 51 */<br /> b = II(b, c, d, a, x[5], S44, 0xfc93a039L); /* 52 */<br /> a = II(a, b, c, d, x[12], S41, 0x655b59c3L); /* 53 */<br /> d = II(d, a, b, c, x[3], S42, 0x8f0ccc92L); /* 54 */<br /> c = II(c, d, a, b, x[10], S43, 0xffeff47dL); /* 55 */<br /> b = II(b, c, d, a, x[1], S44, 0x85845dd1L); /* 56 */<br /> a = II(a, b, c, d, x[8], S41, 0x6fa87e4fL); /* 57 */<br /> d = II(d, a, b, c, x[15], S42, 0xfe2ce6e0L); /* 58 */<br /> c = II(c, d, a, b, x[6], S43, 0xa3014314L); /* 59 */<br /> b = II(b, c, d, a, x[13], S44, 0x4e0811a1L); /* 60 */<br /> a = II(a, b, c, d, x[4], S41, 0xf7537e82L); /* 61 */<br /> d = II(d, a, b, c, x[11], S42, 0xbd3af235L); /* 62 */<br /> c = II(c, d, a, b, x[2], S43, 0x2ad7d2bbL); /* 63 */<br /> b = II(b, c, d, a, x[9], S44, 0xeb86d391L); /* 64 */<br /> state[0] += a;<br /> state[1] += b;<br /> state[2] += c;<br /> state[3] += d;<br /> }</p><p> /*<br /> * Encode把long數組按順序拆成byte數組，因為java的long類型是64bit的， 只拆低32bit，以適應原始C實現的用途<br /> */<br /> private void Encode(byte[] output, long[] input, int len) {<br /> int i, j;<br /> for (i = 0, j = 0; j < len; i++, j += 4) {<br /> output[j] = (byte) (input[i] & 0xffL);<br /> output[j + 1] = (byte) ((input[i] >>> 8) & 0xffL);<br /> output[j + 2] = (byte) ((input[i] >>> 16) & 0xffL);<br /> output[j + 3] = (byte) ((input[i] >>> 24) & 0xffL);<br /> }<br /> }</p><p> /*<br /> * Decode把byte數組按順序合成成long數組，因為java的long類型是64bit的，<br /> * 只合成低32bit，高32bit清零，以適應原始C實現的用途<br /> */<br /> private void Decode(long[] output, byte[] input, int len) {<br /> int i, j;<br /> for (i = 0, j = 0; j < len; i++, j += 4)<br /> output[i] = b2iu(input[j]) | (b2iu(input[j + 1]) << 8)<br /> | (b2iu(input[j + 2]) << 16) | (b2iu(input[j + 3]) << 24);<br /> return;<br /> }</p><p> /*<br /> * b2iu是我寫的一個把byte按照不考慮加號或減號的原則的＂升位＂程式，因為java沒有unsigned運算<br /> */<br /> public static long b2iu(byte b) {<br /> return b < 0 ? b & 0x7F + 128 : b;<br /> }</p><p> /*<br /> * byteHEX()，用來把一個byte類型的數轉換成十六進位的ASCII表示，<br /> * 因為java中的byte的toString無法實現這一點，我們又沒有C語言中的 sprintf(outbuf,"%02X",ib)<br /> */<br /> public static String byteHEX(byte ib) {<br /> char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A',<br /> 'B', 'C', 'D', 'E', 'F' };<br /> char[] ob = new char[2];<br /> ob[0] = Digit[(ib >>> 4) & 0X0F];<br /> ob[1] = Digit[ib & 0X0F];<br /> String s = new String(ob);<br /> return s;<br /> }<br />}

使用方法：

public static void main(String[] args) {
  MD5Code md5 = new MD5Code() ;
  String str = "123456" ;
  System.out.println(md5.getMD5ofStr(str));
 }

無論密碼多長..加密後密碼位元一定。