Java加密算法汇总

原文来自：http://www.iteye.com/topic/243970

 

Base64:

 

  package com.cxlh.mm;  
    
  public class Base64 {  
      final static String baseTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";  
    
      /** 
       * Encode a byte array.  
       *  
       * @param bytes a byte array to be encoded.  
       * @return encoded object as a String object.  
       */  
      public static String encode(byte[] bytes) {  
    
          StringBuffer tmp = new StringBuffer();  
          int i = 0;  
          byte pos;   
    
          for(i=0; i < (bytes.length - bytes.length%3); i+=3) {  
    
              pos = (byte) ((bytes[i] >> 2) & 63);   
              tmp.append(baseTable.charAt(pos));   
    
              pos = (byte) (((bytes[i] & 3) << 4) + ((bytes[i+1] >> 4) & 15));   
              tmp.append(baseTable.charAt( pos ));  
                        
              pos = (byte) (((bytes[i+1] & 15) << 2) + ((bytes[i+2]  >> 6) & 3));  
              tmp.append(baseTable.charAt(pos));  
            
              pos = (byte) (((bytes[i+2]) & 63));  
              tmp.append(baseTable.charAt(pos));  
            
              // Add a new line for each 76 chars.   
              // 76*3/4 = 57  
              if(((i+2)%56) == 0) {  
                  tmp.append("\r\n");  
              }  
          }  
    
          if(bytes.length % 3 != 0) {  
    
              if(bytes.length % 3 == 2) {  
    
                  pos = (byte) ((bytes[i] >> 2) & 63);   
                  tmp.append(baseTable.charAt(pos));   
    
                  pos = (byte) (((bytes[i] & 3) << 4) + ((bytes[i+1] >> 4) & 15));   
                  tmp.append(baseTable.charAt( pos ));  
                            
                  pos = (byte) ((bytes[i+1] & 15) << 2);  
                  tmp.append(baseTable.charAt(pos));  
                
                  tmp.append("=");  
    
              } else if(bytes.length % 3 == 1) {  
                    
                  pos = (byte) ((bytes[i] >> 2) & 63);   
                  tmp.append(baseTable.charAt(pos));   
    
                  pos = (byte) ((bytes[i] & 3) << 4);   
                  tmp.append(baseTable.charAt( pos ));  
                            
                  tmp.append("==");  
              }  
          }  
          return tmp.toString();  
    
      }  
    
      /** 
       * Encode a String object.  
       *  
       * @param src a String object to be encoded with Base64 schema.  
       * @return encoded String object.  
       */  
      public static String encode(String src) {  
            
          return encode(src.getBytes());    
      }  
    
      public static byte[] decode(String src) throws Exception {  
    
          byte[] bytes = null;  
    
          StringBuffer buf = new StringBuffer(src);  
    
          // First, Remove white spaces (\r\n, \t, " ");  
          int i = 0;  
          char c = ' ';  
          char oc = ' ';  
          while( i < buf.length()) {             
              oc = c;   
              c = buf.charAt(i);  
              if( oc == '\r' && c == '\n') {  
                  buf.deleteCharAt(i);  
                  buf.deleteCharAt(i-1);  
                  i -= 2;  
              } else if( c == '\t') {  
                  buf.deleteCharAt(i);  
                  i --;  
              } else if( c == ' ') {  
                  i --;  
              }  
              i++;  
          }  
    
          // The source should consists groups with length of 4 chars.   
          if(buf.length() % 4 != 0) {  
              throw new Exception("Base64 decoding invalid length");  
          }  
    
          // pre-set byte array size.  
          bytes = new byte[3 * (buf.length() / 4)];  
          //int len = 3 * (buf.length() % 4);   
          //System.out.println("Size of Bytes array: " + len);  
          int index = 0;  
            
          // Now decode each group  
          for(i = 0; i < buf.length(); i+=4) {  
    
              byte data = 0;  
              int nGroup = 0;  
    
              for(int j = 0; j < 4; j++) {  
    
                  char theChar = buf.charAt(i + j);   
    
                  if(theChar == '=') {  
                      data = 0;  
                  } else {  
                      data = getBaseTableIndex(theChar);   
                  }  
    
                  if(data == -1) {  
                      throw new Exception("Base64 decoding bad character");  
                  }  
    
                  nGroup = 64*nGroup + data;  
              }  
    
              bytes[index] = (byte) (255 & (nGroup >> 16));  
              index ++;  
    
              bytes[index] = (byte) (255 & (nGroup >> 8));  
              index ++;  
    
              bytes[index] = (byte) (255 & (nGroup));  
              index ++;  
          }  
            
          byte[] newBytes = new byte[index];  
          for(i = 0; i < index; i++) {  
              newBytes[i] = bytes[i];  
          }  
    
          return newBytes;  
      }  
    
      /** 
       * Find index number in base table for a given character.  
       *  
       */  
      protected static byte getBaseTableIndex(char c) {  
            
          byte index = -1;  
    
          for(byte i = 0; i < baseTable.length(); i ++) {  
            
              if(baseTable.charAt(i) == c) {  
                  index = i;  
                  break;  
              }  
          }  
    
          return index;  
      }  
        
      public static void main(String[] args) {  
          String encodedString = Base64.encode("Hello PHPRPC".getBytes());  
          System.out.println(encodedString);  
      }  
  }  

 

MD5:

 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];  
        
      /** 
       * 得到MD5加密后的字符串 
       * @param inbuf 
       * @return 
       */  
      public String getStrToMD5(String inbuf) {  
          md5Init();  
          md5Update(inbuf.getBytes(), inbuf.length());  
          md5Final();  
          digestHexStr = "";  
          for (int i = 0; i < 16; i++) {  
              digestHexStr += byteHEX(digest[i]);  
          }  
          return digestHexStr;  
    
      }  
    
      /* 
        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]);  
          }  
          digestHexStr=digestHexStr.substring(8,24);  
          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();  
          String abc = m.getMD5ofStr("123456");  
          System.out.println(abc);  
      }  
    
 

   复杂加密：

 

 public static String Encrypt(String str) {  
       Security.addProvider(new com.sun.crypto.provider.SunJCE());  
       sun.misc.BASE64Encoder encoder = new sun.misc.BASE64Encoder();  
       String strOut = "";  
       try {  
           // DES算法要求有一个可信任的随机数源  
           SecureRandom sr = new SecureRandom();  
     
           // 从原始密匙数据创建DESKeySpec对象  
           DESKeySpec dks = new DESKeySpec(KEY_STRING.getBytes());  
     
           // 创建一个密匙工厂，然后用它把DESKeySpec转换成  
           // 一个SecretKey对象  
           SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");  
           SecretKey key = keyFactory.generateSecret(dks);  
     
           // Cipher对象实际完成加密操作  
           Cipher cipher = Cipher.getInstance("DES");  
     
           // 用密匙初始化Cipher对象  
           cipher.init(Cipher.ENCRYPT_MODE, key, sr);  
     
           // 现在，获取数据并加密  
           byte data[] = str.getBytes(); /* 用某种方法获取数据 */  
     
           // 正式执行加密操作  
           byte encryptedData[] = cipher.doFinal(data);  
     
           strOut = encoder.encode(encryptedData);  
       } catch (Exception e) {  
           e.printStackTrace();  
       }  
       return strOut;  
   }  
     
   public static String Decrypt(String s) {  
       Security.addProvider(new com.sun.crypto.provider.SunJCE());  
       String strOut = "";  
       sun.misc.BASE64Decoder decoder = new sun.misc.BASE64Decoder();  
       try {  
           // DES算法要求有一个可信任的随机数源  
           SecureRandom sr = new SecureRandom();  
     
           // 从原始密匙数据创建一个DESKeySpec对象  
           DESKeySpec dks = new DESKeySpec(KEY_STRING.getBytes());  
     
           // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成  
           // 一个SecretKey对象  
           SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");  
             
           SecretKey key = keyFactory.generateSecret(dks);  
     
           // Cipher对象实际完成解密操作  
           Cipher cipher = Cipher.getInstance("DES");  
     
           // 用密匙初始化Cipher对象  
           cipher.init(Cipher.DECRYPT_MODE, key, sr);  
     
           // 现在，获取数据并解密  
           byte encryptedData[] = decoder.decodeBuffer(s); /* 获得经过加密的数据 */  
     
           // 正式执行解密操作  
           byte decryptedData[] = cipher.doFinal(encryptedData);  
     
           strOut = new String(decryptedData);  
       } catch (Exception e) {  
           e.printStackTrace();  
       }  
       return strOut;  
   }  
     
   public static void main(String[] args){  
       String a=Encrypt("aaa");  
         
       System.out.print(a);  
         
       String b=Decrypt("5991bf21cbe98232".toUpperCase());  
         
       System.out.print(b);