Java中byte类型学习及DES代码
最近在看DES加密算法的java版本，看到好多对byte类型负数的转化，之前一直以为byte是unsigned 的，后来经过查阅得知，java没有unsigned数据类型的，所有类型的数据都是进行的signed运算的，所以在以后使用无符号类型时都要记着要手动写函数转化，经过这一遭，对java的理解又深了一步
下面是DES的代码，与大家分享（以下是我调试通过的，可以直接运行的）
package com.mz.file;public class DESEncrypt {//十六进制符号表static final char[] hex = new char[] {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};//默认密钥private String encryptKey = "abcd1234";//密钥缩位映射表1，共56位//左边28位static final int []keyMapC1 =new int[]{57,49,41,33,25,17,9, 1,58,50,42,34,26,18,10,2,59,51,43,35,27, 19,11,3,60,52,44,36};//右边28位static final int []keyMapD1 = new int[]{63,55,47,39,31,23,15, 7,62,54,46,38,30,22,14,6,61,53,45,37,29,21,13,5,28,20,12,4};//密钥缩位表2，共48位static final int []keyMap2 = new int[]{14,17,11,24,1,5, 3,28,15,6,21,10,23,19,12,4,26,8,16,7,27,20,13,2, 41,52,31,37,47,55,30,40,51,45,33,48,44,49,39,56,34,53, 46,42,50,36,29,32};//密钥变换循环移位表,16位static final int []ccmovebit = new int[]{1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};//密钥产生过程中使用的临时数组private int [][]C = new int[17][28];private int [][]D = new int[17][28];private int [][]keyMap = new int[17][48];//开始S盒加密时换位表1,64位static final int ip[] = {58,50,42,34,26,18,10,2,60,52,44,36,28,20,12,4, 62,54,46,38,30,22,14,6,64,56,48,40,32,24,16,8, 57,49,41,33,25,17,9,1,59,51,43,35,27,19,11,3, 61,53,45,37,29,21,13,5,63,55,47,39,31,23,15,7 };//结束S盒加密时换位表2,64位static final int _ip[] = {40,8,48,16,56,24,64,32,39,7,47,15,55,23,63,31, 38,6,46,14,54,22,62,30,37,5,45,13,53,21,61,29, 36,4,44,12,52,20,60,28,35,3,43,11,51,19,59,27, 34,2,42,10,50,18,58,26,33,1,41,9,49,17,57,25 }; //放大换位表: 32bit->48bitstatic final int e[] = {32,1, 2, 3, 4, 5,4, 5, 6, 7, 8, 9, 8, 9, 10,11,12,13,12,13,14,15,16,17, 16,17,18,19,20,21,20,21,22,23,24,25, 24,25,26,27,28,29,28,29,30,31,32,1 };//缩小换位表：48bit->32bitstatic final int e2[] = {16,7,20,21,29,12,28,17,1,15,23,26, 5,18,31,10,2,8,24,14,32,27,3,9,19,13,30,6,22,11,4,25 };//S盒矩阵static final int sBoxMetrix[][][]= new int[][][]{ { {14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7}, {0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8}, {4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0}, {15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13} }, { {15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10}, {3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5}, {0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15}, {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9} }, { {10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8}, {13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1}, {13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7}, {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12} }, { {7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15}, {13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9}, {10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4}, {3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14} }, { {2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9}, {14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6}, {4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14}, {11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3}, }, { {12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11}, {10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8}, {9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6}, {4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13} }, { {4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1}, {13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6}, {1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2}, {6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12} }, { {13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7}, {1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2}, {7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8}, {2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11} } };/** * 描述： 构造方法，使用默认密钥--abcd1234 */DESEncrypt(){genSubKey();}/** * 描述： 构造方法 * @param key 指定加密密钥 */DESEncrypt(String key){this.encryptKey = key;genSubKey();}/** * 描述：将Byte数组存储Bit型数据转换为Byte数组存储的Byte型数据 * 作者：李海伟 * 时间：2012-3-16 上午11:38:40 * @param a 存储Bit型数据的数组 * @param b 存储Byte型数据的数组 */private void bit2Byte(byte[] a,byte[] b){int i=0,value=0,base=0;for(i=0;i<b.length;i++){base = i*8;value = a[base+0]*128 + a[base+1]*64 + a[base+2]*32 + a[base+3]*16 + a[base+4]*8 + a[base+5]*4 + a[base+6]*2 +a[base+7]*1;b[i] = (byte)value;}}/** * 描述：将ASCII码字符串转换为二进制数组 * 作者：李海伟 * 时间：2012-3-7 下午03:44:44 * @param bit 8字节的源字符串 * @param des 转换后的二进制串（位码由高到低排列） * @return */private void ASCII2Bit( byte bit[],byte des[]){for(int i=0;i<8;i++){for(int j=0;j<8;j++){des[i*8+j] = (byte)((bit[i] >> (7-j))&0x01);}}}/** * 描述：将二进制数组转化为十六进制字符串 * 作者：李海伟 * 时间：2012-3-14 下午04:42:31 * @param a 以byte数组存储的二进制数据 * @return 十六进制的字符串 */private String bit2Hex(byte[]a){String strRtn = "";int length = a.length;int i=0,value=0;for(i=0;i<length;i+=4){int baseIndex = i;value = a[baseIndex+0]*8+a[baseIndex+1]*4+a[baseIndex+2]*2+a[baseIndex+3]*1;strRtn += hex[value];}return strRtn;}/** * 描述：把十六进制的字符串转换为比特串 * 作者：李海伟 * 时间：2012-3-16 上午10:18:41 * @param hex * @param bit */private void hex2Bit(String hex,byte []bit){String strTmp ="";int i = 0;for(i=0;i<hex.length();i++){switch(hex.charAt(i)){case '0':strTmp += "0000";break;case '1':strTmp += "0001";break;case '2':strTmp += "0010";break;case '3':strTmp += "0011";break;case '4':strTmp += "0100";break;case '5':strTmp += "0101";break;case '6':strTmp += "0110";break;case '7':strTmp += "0111";break;case '8':strTmp += "1000";break;case '9':strTmp += "1001";break;case 'A':strTmp += "1010";break;case 'B':strTmp += "1011";break;case 'C':strTmp += "1100";break;case 'D':strTmp += "1101";break;case 'E':strTmp += "1110";break;case 'F':strTmp += "1111";break;}}for(i=0;i<strTmp.length();i++){bit[i]=(byte)(strTmp.charAt(i)-48);}}/** * 描述：根据给定的字符串生成加密秘钥 * 作者：李海伟 * 时间：2012-3-14 下午01:53:16 * @param oldKey * @param newKey */private void genSubKey(){ int i, k, rol = 0; int []tmp = new int[56]; //16次循环左移对应的左移位数 byte []oldKey = this.encryptKey.getBytes(); byte[] oldkey_byte = new byte[64]; ASCII2Bit(oldKey, oldkey_byte); //IP变换,分为C,D两部分 for(i=0;i<28;i++){ C[0][i] = oldkey_byte[keyMapC1[i]-1]; } for(i=0;i<28;i++){ D[0][i] = oldkey_byte[keyMapD1[i]-1]; } //分别生成16个子密钥 for(i = 1; i < 17; i++) { //循环左移 rol = ccmovebit[i-1]; //合并左移后的结果 for(k = 0; k < 28; k++){ C[i][k] = C[i-1][(k+rol)%28]; D[i][k] = D[i-1][(k+rol)%28]; } //合并C和D for(k=0;k<28;k++){ tmp[k] = C[i][k]; tmp[k+28] = D[i][k]; } //位变换 for(k = 0; k < 48; k++) keyMap[i][k] = tmp[keyMap2[k] - 1]; } }/** * 描述：进行S盒变换 * 作者：李海伟 * 时间：2012-3-16 上午09:36:26 * @param n 第n轮加密 * @param ll 加密前左部分 * @param rr 加密前右部分 * @param LL 加密后左部分 * @param RR 加密后右部分 */private void F_Sbox(int n, byte[] ll, byte[] rr, byte[] LL, byte[] RR){int i, j,y,z,k,m;byte[] buffer = new byte[64], tmp = new byte[32],rtnByte = new byte[8] ;for (i = 0; i < 48; i++) //明文32比特变48比特 buffer[i] = rr[e[i] - 1];//Ri与Ki进行不进位加法for (i = 0; i < 48; i++) buffer[i] = (byte) ((buffer[i] + (byte)(keyMap[n][i]))& 0x01);m=0;for(i=0;i<8;i++){j = 6 * i;y = (int)buffer[j]*2 + (int)buffer[j+5];z = (int)(buffer[j + 1] * 8 + buffer[j + 2] * 4 + buffer[j + 3] * 2+ buffer[j + 4]);rtnByte[i] = (byte)(sBoxMetrix[i][y][z]);y = 3; for (k = 0; k < 4; k++) { tmp[m++] = (byte)((rtnByte[i] >>> y) & 0x01); y--; } }for (k = 0; k < 32; k++) buffer[k] = tmp[e2[k] - 1]; for (k = 0; k < 32; k++) RR[k] = (byte)((buffer[k] + ll[k]) & 1); for (k = 0; k < 32; k++) LL[k] = rr[k];}/** * 描述：分块对明文加密，每块包含8个字节 * 作者：李海伟 * 时间：2012-3-14 下午04:59:20 * @param m_byte * @return */private String encryptByBlock(byte[]m_byte){ byte [] t_bit = new byte [64]; byte[] l_byte = new byte[32]; byte[] r_byte = new byte[32]; byte[][] l_bit = new byte[17][32]; byte[][] r_bit = new byte[17][32]; byte []c_bit = new byte[64]; byte[] e_bit = new byte[64]; //数组初始化 int i, j; //将待加密字串变换成01串 ASCII2Bit(m_byte, t_bit); //按照ip表对待加密字串进行位变换,分为左右两部分 for(i = 0; i < 32; i++) { l_byte[i] = t_bit[ip[i]-1]; r_byte[i] = t_bit[ip[i+32]-1]; } //16轮加密 for(i=1;i<17;i++){ F_Sbox(i, l_byte, r_byte, l_bit[i], r_bit[i]); for (j = 0; j < 32; j++) { l_byte[j] = l_bit[i][j]; r_byte[j] = r_bit[i][j]; } } //组合最终迭代结果并第二次IP变换 for(i=0;i<32;i++){ c_bit[i] = r_bit[16][i]; c_bit[i+32] = l_bit[16][i]; } for(i = 0; i < 64; i++) { e_bit[i] = c_bit[_ip[i]-1]; } String encryptText = bit2Hex(e_bit); return encryptText;}/** * 描述：分块解密密文数据 * 作者：李海伟 * 时间：2012-3-16 上午11:34:42 * @param enTxt * @param b */private void dencryptByBlock(String txt,byte []b,int k){ int i, j; byte[] l_byte = new byte[32]; byte[] r_byte = new byte[32]; byte[][] l_bit = new byte[17][32]; byte[][] r_bit = new byte[17][32]; byte []c_bit = new byte[64]; byte[] e_bit = new byte[64]; byte []enTxt = new byte[64];//按照ip表对待解密字串进行位变换,分为左右两部分 hex2Bit(txt,enTxt); for(i = 0; i < 32; i++) { l_byte[i] = enTxt[ip[i]-1]; r_byte[i] = enTxt[ip[i+32]-1]; } //16轮解密 for(i=16;i>0;i--){ F_Sbox(i, l_byte, r_byte, l_bit[i], r_bit[i]); for (j = 0; j < 32; j++) { l_byte[j] = l_bit[i][j]; r_byte[j] = r_bit[i][j]; } }//组合最终迭代结果并第二次IP变换 for(i=0;i<32;i++){ c_bit[i] = r_bit[1][i]; c_bit[i+32] = l_bit[1][i]; } for(i = 0; i < 64; i++) { e_bit[i] = c_bit[_ip[i]-1]; } for(i=0;i<64;i++){ b[i]=e_bit[i]; }}/** * 描述：对传入的明文字符串进行加密 * 作者：李海伟 * 时间：2012-3-15 上午09:51:19 * @param txt 待加密明文字符串 * @return加密后的密文字符串 */public String encrypt(String txt){ int dataLen = txt.length();//待加密数据的长度 byte []in = txt.getBytes(); byte te8bit[]=new byte[]{0,0,0,0,0,0,0,0}; // 这是待加密字串的调整长度 // 如果原始长度是8的整数倍，则调整长度的值和原来的长度一样 // 如果原始长度不是8的整数倍，则调整长度的值是能被8整除且不大于原来长度的最大整数。 //也就是不需要补齐的块的总长度。 int te_fixlen = dataLen - (dataLen % 8); // 将待加密密文以8为单位分段，把最后长度不足8的一段存储到te8bit中。 for(int i = 0; i < (dataLen % 8); i++) te8bit[i] = in[te_fixlen + i]; String strRtn = ""; // 将待加密字串分以8字节为单位分段加密 byte src[]= new byte[8]; for(int i = 0; i < te_fixlen; i += 8) { for(int k=0;k<8;k++) { src[k] = in[i+k]; } strRtn += encryptByBlock(src); } // 如果待加密字串不是8的整数倍，则将最后一段补齐（补0）后加密 if(dataLen % 8 != 0) strRtn += encryptByBlock(te8bit); return strRtn;}/** * 描述：对传入密文进行解密操作，并返回原文 * 作者：李海伟 * 时间：2012-3-19 上午10:11:31 * @param m_txt 密文字符串 * @param len 原文长度 * @return */public String dencrypt(String m_txt,int len){byte b_bit[] = new byte[64],a_byte[]= new byte[8],c_byte[] = new byte[len];int i=0,j=0,k=0;for(i=0;i<m_txt.length();i=i+16){dencryptByBlock(m_txt.substring(i, i+16), b_bit,1);bit2Byte(b_bit,a_byte);k=0;while((j<len)&&(k<a_byte.length)){c_byte[j++] = a_byte[k++];}if(!(j<len)){break;}}return new String(c_byte);}/** * 描述：以字符串形式返回当前使用的密钥 * 作者：李海伟 * 时间：2012-3-15 上午11:25:52 */public String getKey(){return this.encryptKey;}public void test (){byte []a= new byte[32*4];String srcStr = "0020321745";//002032174String str=encrypt(srcStr);System.out.println("原文：["+srcStr+"]\n加密后的密文：["+str+"]");String srcStr2 = dencrypt(str,srcStr.getBytes().length);System.out.println("解密后的原文："+srcStr2);}public static void main(String []args){DESEncrypt des = new DESEncrypt("abcdabcd");des.test();System.out.println("excute success!");}}