这是数据加密标准（DES）算法实现，网上有很多C/C++版本的，特写一个JAVA版本的，主要是想练练自己JAVA的编程能力，如果有不妥当的地方希望大家能指正，或者给出更好的建议，其实现代码如下：
/** * * @author Davy Chen */ public class DES { //初始换位IP表 byte 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 }; //逆初始换位IP^-1表 byte IIP[] = { 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 }; //密钥置换PC-1表 byte 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 }; //密钥置换PC-2表 byte 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 }; //E的选位表 byte[] E_box = { 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 }; //DES的中的S-Boxes byte[][][] S_box = { { {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} } }; //S-Box之后的32位置换P表 byte[] P_box = { 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 }; byte[][] Lpart = new byte[4][8]; byte[][] Rpart = new byte[4][8]; //声明一个三维数组用来存储加密过程产生的16个密码 byte[][][] saveKey = new byte[16][8][6]; //保存加密后的二进制密文 //public byte[][] encryptTextBits; //初始置换IP private byte[][] initailDisplacementIP(byte[][] in) { byte[][] out = new byte[8][8]; for (int i = 0; i < 64; i++) { out[i / 8][i % 8] = in[(IP[i] - 1) / 8][(IP[i] - 1) % 8]; } //System.arraycopy(out, 0, in, 0, 8);//源数组中位置在 srcPos 到 srcPos+length-1 之间的组件被分别复制到目标数组中的 destPos 到 destPos+length-1 位置 return out; }//ip结束 public byte[][][] generateKey(byte[] key) { //压缩变换PC-1后分割的结果C、D byte[][] C = new byte[4][7]; byte[][] D = new byte[4][7]; //生成子密钥 byte[][] bitArray2 = new byte[8][8]; for (int i = 0; i < 8; i++) { bitArray2[i] = Change.byteToBitArray(key[i]); } //压缩变换PC-1 bitArray2 = compressionTransformPC_1(bitArray2); //密钥分割 // 将bitArray2经过PC1后的数组拆分成2组 for (int i = 0; i < 8; i++) { for (int j = 0; j < 7; j++) { if (i < 4) { C[i][j] = bitArray2[i][j]; } else { D[i - 4][j] = bitArray2[i][j]; } } } for (int i = 0; i < 16; i++) { //向左移1位的情况 if (i == 0 || i == 1 || i == 8 || i == 15) { leftShift(C); leftShift(D); } //向左移动2位的情况 else { leftShift(C); leftShift(C); leftShift(D); leftShift(D); } //在一个数组中存储K1-K16以便解密使用 saveKey[i] = compressionTransformPC_2(C, D); } return saveKey; } /** * DES加密 * @param plainText * @param key */ public String encrypt(byte[] plainText, byte[][][] key) { //将byteArray中的位取出并扩展成字节放在bitArray中 byte[][] bitArray = new byte[8][8]; for (int i = 0; i < 8; i++) { bitArray[i] = Change.byteToBitArray(plainText[i]); } //完成初始置换IP bitArray = initailDisplacementIP(bitArray); //将bitArray分配给2个数组Lpart和Rpart for (int i = 0; i < 8; i++) { for (int j = 0; j < 8; j++) { if (i < 4) { Lpart[i][j] = bitArray[i][j]; } else { Rpart[i - 4][j] = bitArray[i][j]; } } } byte[][] temp; //进行16轮的加密变换 for (int i = 0; i < 16; i++) { // 用临时数组temp保存明文右半部分 temp = (byte[][]) Rpart.clone(); XOR(Lpart, f(Rpart, key[i])); Rpart = Lpart; Lpart = temp; } // 左右两部分合并然后最终置换,由于最后一次循环之后左边和右边进行了一次交换，所以这里参数的顺序是Rpart在前Lpart在后 byte[][] encryptTextBits = contraryInitailDisplacementIIP(Rpart, Lpart); // 转化为字节，然后转化为字符 byte[] out = new byte[8]; for (int i = 0; i < 8; i++) { out[i] = Change.bitToByteArray(encryptTextBits[i]); } //输出16进制形式的字符串 return Change.bytesToHexString(out); } /** * DES解密 * @param plainText * @param key */ public String decrypt(byte[] encryptText, byte[][][] key) { //将byteArray中的位取出并扩展成字节放在bitArraye中 byte[][] bitArray = new byte[8][8]; for (int i = 0; i < 8; i++) { bitArray[i] = Change.byteToBitArray(encryptText[i]); } //完成初始置换IP bitArray = initailDisplacementIP(bitArray); for (int i = 0; i < 4; i++) { for (int j = 0; j < 8; j++) { Rpart[i][j] = bitArray[i][j]; Lpart[i][j] = bitArray[i + 4][j]; } } byte[][] temp; for (int i = 15; i >= 0; i--) { temp = (byte[][]) Lpart.clone(); XOR(Rpart, f(Lpart, key[i])); Lpart = Rpart; Rpart = temp; } byte[][] result = contraryInitailDisplacementIIP(Lpart, Rpart); //转化为字节，然后转化为字符 byte[] out = new byte[8]; for (int i = 0; i < 8; i++) { out[i] = Change.bitToByteArray(result[i]); } //输出16进制形式的字符串 return Change.bytesToHexString(out); } public static void main(String[] args) { DES des = new DES(); //二进制形式的原文 byte[][] plainTextBit = { {(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01}, {(byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01}, {(byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x01}, {(byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01}, {(byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01}, {(byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01}, {(byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x01}, {(byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01} }; //二进制形式的密钥 byte[][] keyBit = { {(byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01}, {(byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x00}, {(byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01}, {(byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01}, {(byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01}, {(byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00}, {(byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01}, {(byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x01, (byte) 0x00, (byte) 0x00, (byte) 0x00, (byte) 0x01} }; //转换为byte数组 byte[] plainTextByte = new byte[8]; byte[] keyByte = new byte[8]; for (int i = 0; i < 8; i++) { plainTextByte[i] = Change.bitToByteArray(plainTextBit[i]); keyByte[i] = Change.bitToByteArray(keyBit[i]); } byte[][][] key = des.generateKey(keyByte); byte[] plainText2 = {(byte) 0x11, (byte) 0x12, (byte) 0x13, (byte) 0x14, (byte) 0x15, (byte) 0x16, (byte) 0x17, (byte) 0x18}; System.out.println("原文1为：" + Change.bytesToHexString(plainTextByte)); System.out.println("原文2为：" + Change.bytesToHexString(plainText2)); //输出密文 String encrypt = des.encrypt(plainTextByte, key); String encrypt2 = des.encrypt(plainText2, key); System.out.println("encrypt1=" + encrypt); System.out.println("encrypt2=" + encrypt2); byte[] encryptByte = Change.hexStringToBytes(encrypt); byte[] encryptByte2 = Change.hexStringToBytes(encrypt2); //输出原文 System.out.println("decrypt1=" + des.decrypt(encryptByte, key)); System.out.println("decrypt2=" + des.decrypt(encryptByte, key)); System.out.println("decrypt2=" + des.decrypt(encryptByte2, key)); } /** * PC-1压缩变换 */ private byte[][] compressionTransformPC_1(byte[][] in) { byte[][] temp = new byte[8][7]; for (int i = 0; i < 56; i++) { temp[i / 7][i % 7] = in[(PC_1[i] - 1) / 8][(PC_1[i] - 1) % 8]; } return temp; } /** * 左移函数 * @param C */ private void leftShift(byte[][] b) { byte temp = b[0][0]; for (int i = 0; i < 4; i++) { for (int j = 0; j < 6; j++) { b[i][j] = b[i][j + 1]; if (i == 3) { continue; } if (j == 5) { b[i][6] = b[i + 1][0]; } } } b[3][6] = temp; } /** * PC-2压缩变换 * @param C * @param D * @return */ private byte[][] compressionTransformPC_2(byte[][] C, byte[][] D) { byte[][] out = new byte[8][6]; byte[][] temp = new byte[8][7]; //将C和D合并56位的 for (int i = 0; i < 28; i++) { temp[i / 7][i % 7] = C[i / 7][i % 7]; temp[i / 7 + 4][i % 7] = D[i / 7][i % 7]; } for (int i = 0; i < 48; i++) { out[i / 6][i % 6] = temp[(PC_2[i] - 1) / 7][(PC_2[i] - 1) % 7]; } return out; } private byte[][] f(byte[][] rPart, byte[][] key) { byte[][] temp; //32位扩展到48位 rPart = EBox(rPart); XOR(rPart, key); temp = Sbox(rPart); return Pbox(temp); } /** * 异或 * @param a * @param b */ private void XOR(byte[][] a, byte[][] b) { for (int i = 0; i < a.length; i++) { for (int j = 0; j < a[i].length; j++) { a[i][j] ^= b[i][j]; } } } /** * E-盒置换 * @param in * @return */ private byte[][] EBox(byte[][] in) { byte[][] out = new byte[8][6]; for (int i = 0; i < 48; i++) { out[i / 6][i % 6] = in[(E_box[i] - 1) / 8][(E_box[i] - 1) % 8]; } return out; } /** * S-盒替代 * @param rPart * @return */ private byte[][] Sbox(byte[][] in) { byte[] temp = new byte[8]; byte[][] out = new byte[8][4]; //行号，列号 int m, n; for (int i = 0; i < 8; i++) { m = in[i][0] * 2 + in[i][5]; n = in[i][1] * 8 + in[i][2] * 4 + in[i][3] * 2 + in[i][4]; temp[i] = (byte) S_box[i][m][n]; } for (int i = 0; i < 8; i++) { for (int j = 3; j >= 0; j--) { out[i][j] = (byte) (temp[i] & 0x01); temp[i] >>= 1; } } return out; } private byte[][] Pbox(byte[][] in) { byte[][] temp = new byte[4][8]; for (int i = 0; i < 32; i++) { temp[i / 8][i % 8] = in[(P_box[i] - 1) / 4][(P_box[i] - 1) % 4]; } return temp; } private byte[][] contraryInitailDisplacementIIP(byte[][] Rpart, byte[][] Lpart) { byte[][] out = new byte[8][8]; byte[][] temp = new byte[8][8]; for (int i = 0; i < 4; i++) { for (int j = 0; j < 8; j++) { temp[i][j] = Rpart[i][j]; temp[i + 4][j] = Lpart[i][j]; } } for (int i = 0; i < 64; i++) { out[i / 8][i % 8] = temp[(IIP[i] - 1) / 8][(IIP[i] - 1) % 8]; } return out; } }
