[置顶] Android/java源代码实现DES算法原理+整理

// 初始置换表 private static final int[] IP_Table = { 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 };

int[] M = new int[64];//IP置换后的数据 for (i = 0; i < 64; i++) { M[i] = timeData[IP_Table[i] - 1];// 明文数据初始置换(IP置换) }//int[] timeData是64位2进制原始数据

// 扩大置换E表 private static final int[] E_Table = { 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 }; // P-盒置换 private static final int[] P_Table = { 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 }; // PC⑴ private static final int[] PC_1 = { 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, 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 }; // PC⑵ private static final int[] PC_2 = { 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 }; // 循环左移位数表 private static final int[] LOOP_left = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; // S-盒1 private static final int S_Box1[][] = { { 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 } }; // S2 private static final int S_BOX2[][] = { { 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 } }; // S3 private static final int S_BOX3[][] = { { 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 } }; // S4 private static final int S_BOX4[][] = { { 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 } }; // S5 private static final int S_BOX5[][] = { { 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 } }; // S6 private static final int S_BOX6[][] = { { 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 } }; // S7 private static final int S_BOX7[][] = { { 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 } }; // S8 private static final int S_BOX8[][] = { { 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 } }; private static final int[][][] S_BOX = { S_Box1, S_BOX2, S_BOX3, S_BOX4, S_BOX5, S_BOX6, S_BOX7, S_BOX8 };

/** * 循环左移 * * @param k * 子密钥 * @param offset * 循环左移的位数 */ private void LeftBitMove(int[] k, int offset) { int i; int[] c0 = new int[28]; int[] d0 = new int[28]; int[] c1 = new int[28]; int[] d1 = new int[28]; for (i = 0; i < 28; i++) { c0[i] = k[i]; d0[i] = k[i + 28]; } if (offset == 1) {// 循环左移1位 for (i = 0; i < 27; i++) { c1[i] = c0[i + 1]; d1[i] = d0[i + 1]; } c1[27] = c0[27]; d1[27] = d0[27]; } else if (offset == 2) {// 循环左移2位 for (i = 0; i < 26; i++) { c1[i] = c0[i + 2]; d1[i] = d0[i + 2]; } c1[26] = c0[0]; d1[26] = d0[0]; c1[27] = c0[1]; d1[27] = d0[1]; } for (i = 0; i < 28; i++) { k[i] = c1[i]; k[i + 28] = d1[i]; } }

/** * 初始化子密钥 * * @param key * 56位密钥 * @param keyarray * 子密钥数组 */ private void KeyInitialize(int[] key, int[][] keyarray) { int i; int j; int[] K0 = new int[56]; for (i = 0; i < 56; i++) {// PC_1置换 K0[i] = key[PC_1[i] - 1]; } for (i = 0; i < 16; i++) {// 进行106次，分别得到16个子密钥 LeftBitMove(K0, LOOP_left[i]);// 循环左移 for (j = 0; j < 48; j++) {// 循环左移以后进行PC_2置换得到子密钥 keyarray[i][j] = K0[PC_2[j] - 1];// 生成16个48位的子密钥 } } }

/** * * @param M * 64位经过IP置换后的明文数据 * @param times * 迭代轮数 * @param flag * 1为加密 * @param keyarray * 子密钥数组 */ private void functionF(int[] M, int times, int flag, int[][] keyarray) { int i; int j; int x = 0; int y = 0; int[] L0 = new int[32]; int[] R0 = new int[32]; int[] L1 = new int[32]; int[] R1 = new int[32]; int[] RE = new int[48];// E扩大置换以后并且与子密钥异或运算得到48位数据 int[][] S = new int[8][6];// S盒输入数据8组6位 // S盒数据是6位输入，4位输出 int[] sBoxData = new int[8]; int[] sValue = new int[32]; int[] RP = new int[32]; for (i = 0; i < 32; i++) {// 将明文分成左右两部份 L0[i] = M[i]; R0[i] = M[i + 32]; } for (i = 0; i < 48; i++) {// 右半部分进行扩大E置换,得到48位RE RE[i] = R0[E_Table[i] - 1]; RE[i] = RE[i] + keyarray[times][i];// 与子密钥按位做不进位加法运算（R0和子密钥做异或运算） if (RE[i] == 2) { RE[i] = 0; } } for (i = 0; i < 8; i++) { for (j = 0; j < 6; j++) { S[i][j] = RE[(i * 6) + j]; } // 把扩大以后的数据分成8组6位的数组 //在上1篇讲到，S盒的计算方法，例如Data = D0D1D2D3D4D5（10进制）;则对应的S盒行是D0D5的值，对应的S盒列是D1D2D3D4的值。 //所以行=D0D5，用2进制表示是D0*2+D1*1等价于(D0<<1)+D5 //列=D1D2D3D4，用2进制表示是(D1*8+D2*4+D3*2+D4*1)等价于((D1<<3)+(D2<<2)+(D3<<1)+D4) //注意左移运算要用括号包围起来，由于存在运算优先级，如果没有使用括号，会运算出错 x = (S[i][0] << 1) + S[i][5]; y = (S[i][1] << 3) + (S[i][2] << 2) + (S[i][3] << 1) + (S[i][4]); sBoxData[i] = S_BOX[i][x][y];// 经过S盒得到8个10进制数字 for (j = 0; j < 4; j++) {// 把10进制数字转成4位2进制 sValue[(i * 4 + 3) - j] = sBoxData[i] % 2; sBoxData[i] = sBoxData[i] / 2; } } // 经过S盒得到32位数组 for (i = 0; i < 32; i++) { RP[i] = sValue[P_Table[i] - 1];// P盒置换得到数组就是函数f终究数组 // 左右进行交换 L1[i] = R0[i]; R1[i] = L0[i] + RP[i]; if (R1[i] == 2) { R1[i] = 0; } // 注意最后1次和第1次变换时，左右不进行交换 if ((flag == 0) && (times == 0) || ((flag == 1) && (times == 15))) {// 第1次和最后1次再交换1次实现不变 M[i] = R1[i]; M[i + 32] = L1[i]; } else { M[i] = L1[i]; M[i + 32] = R1[i]; } } }

/** * IP置换+函数F+逆置换 * @param timeData * @param flag * @param keyarray * @return */ private byte[] Encrypt(int[] timeData, int flag, int[][] keyarray) { int i = 0; int[] M = new int[64]; int[] MIP_1 = new int[64]; byte[] encrypt = new byte[8]; for (i = 0; i < 64; i++) { M[i] = timeData[IP_Table[i] - 1];// 明文数据初始置换(IP置换) } if (flag == 1) {// 加密 for (i = 0; i < 16; i++) { functionF(M, i, flag, keyarray); } } else if (flag == 0) {// 解密:在上1篇说过，DES算法加密和解密可使用相同的算法。加密和解密唯1不同的是秘钥的次序是相反的 for (i = 15; i >= 0; i--) { functionF(M, i, flag, keyarray); } } // 逆运算 for (i = 0; i < 64; i++) { MIP_1[i] = M[IPR_Table[i] - 1]; } // 返回加密数据 GetEncryptResultOfByteArray(MIP_1, encrypt); return encrypt; }

/** * 将64位2进制数据的数组转换成为8个整数 * * @param data * @param value */ private void GetEncryptResultOfByteArray(int[] data, byte[] value) { int i, j; for (i = 0; i < 8; i++) { for (j = 0; j < 8; j++) {// i*8等价于i<<3 value[i] += data[i * 8 + j] << (7 - j);// 每位2进制数据乘于2的(7-j)次方，就是每位2进制左移(7-j) } } // 如果绝对值大于255则是负数 for (i = 0; i < 8; i++) { value[i] %= 256; if (value[i] > 128) { value[i] -= 255; } } }

/** * 格式化字节数组,添加填充位 * @param data * @param flag * @return */ private byte[] ByteDataFormat(byte[] data, int flag) { int len = data.length; int padlen = 8 - (len % 8); int newlen = len + padlen;// 8的倍数长度 byte[] newdata = new byte[newlen]; System.arraycopy(data, 0, newdata, 0, len); for (int i = len; i < newlen; i++) {// 易错点，i=len newdata[i] = (byte) padlen;//随便填充任何值，不1定非要padlen } return newdata; }

int[] keydata = new int[64];// 2进制加密数据 int[] encryptdata = new int[64];// 加密操作完成后的字节数据 byte[] EncrypeCode = new byte[8];// 密钥初始化成2维数组 int[][] KeyArray = new int[16][48];// 将密钥字节数组转换成2进制字节数组 byte[] bytekey;

public MyDES() { String key = "abcdefgh"; String data = "qwertyui"; // key = "原始秘钥"; // data = "原始数据"; this.bytekey = key.getBytes(); MyUtils.log("加密前明文：" + data); byte[] result = DesEncrypt(data.getBytes(), 1); MyUtils.log("加密后密文：" + new String(result)); MyUtils.log("解密后明文：" + new String(DesEncrypt(result, 0))); } private byte[] DesEncrypt(byte[] des_data, int flag) { byte[] format_key = ByteDataFormat(bytekey, flag); byte[] format_data = ByteDataFormat(des_data, flag); int datalen = format_data.length; int unitcount = datalen / 8; byte[] result_data = new byte[datalen]; for (int i = 0; i < unitcount; i++) { byte[] tmpkey = new byte[8]; byte[] tmpdata = new byte[8]; System.arraycopy(format_key, 0, tmpkey, 0, 8); System.arraycopy(format_data, i * 8, tmpdata, 0, 8); byte[] tmpresult = UnitDes(tmpkey, tmpdata, flag); System.arraycopy(tmpresult, 0, result_data, i * 8, 8); } byte[] decryptbytearray = null; if (flag == 0) {// 解密 int total_len = datalen; int delete_len = result_data[total_len - 8 - 1]; delete_len = ((delete_len >= 1) && (delete_len <= 8)) ? delete_len : 0; decryptbytearray = new byte[total_len - delete_len - 8]; boolean del_flag = true; for (int k = 0; k < delete_len; k++) { if (delete_len != result_data[total_len - 8 - (k + 1)]) { del_flag = false; } } if (del_flag) { System.arraycopy(result_data, 0, decryptbytearray, 0, total_len - delete_len - 8); } } return (flag == 1) ? result_data : decryptbytearray; } /** * @return */ private byte[] UnitDes(byte[] des_key, byte[] des_data, int flag) { if ((des_key.length != 8) || (des_data.length != 8) || ((flag != 0) && (flag != 1))) {// 检测输入参数格式是不是正确，毛病直接返回空值null throw new RuntimeException("Data Format Error!"); } int flags = flag; int[] keydata = new int[64];// 2进制加密密钥 int[] encryptdata = new int[64];// 2进制加密数据 byte[] EncryptCode = new byte[8];// 加密操作完成后的字节数组 int[][] KeyArray = new int[16][48];// 密钥初始化成2维数组 keydata = ReadDataToBinnaryIntArray(des_key);// 将密钥字节数组转换成2进制 encryptdata = ReadDataToBinnaryIntArray(des_data);// 将加密数据字节数组转换成2进制字节数组 KeyInitialize(keydata, KeyArray);// 初始化密钥为2位密钥数组 EncryptCode = Encrypt(encryptdata, flags, KeyArray);// 履行加密解密操作 return EncryptCode; }