加密代码实现：
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#include <iostream> #include <string> #include <string.h> #include <unistd.h> using namespace std; int Check(string s) { //检查输入的字符串是否为纯英文 int i = 0; while (s[i] != '\0') { if (!((s[i] >= 'a'&&s[i] <= 'z') || (s[i] >= 'A'&&s[i] <= 'Z'))) { cout << "Error!Please enter again!" << endl; return 1; } i++; } return 0; } //Playfair cipher构造matrix key char(*matrixkey(char(&matrix)[5][5]))[5]{ int i = 0,j = 0,k = 0,n = 0; string keyword; int flag = 0; string key(20, '\0'); string rule(50, '\0'); string alpha("abcdefghijklmnopqrstuvwxyz"); do { //输入keyword fflush(stdin); cout << "select a keyword:"; cin >> keyword; flag = Check(keyword); } while (flag); for (i = 0; i < keyword.length(); i++) { //提取key flag = 1; if (keyword[i] == 'j') keyword[i] = i; for (j = 0; j < i; j++) { if (key[j] == keyword[i]) flag = 0; } if (flag) key[k++] = keyword[i]; } key[k] = '\0'; //组合对应表 while (key[n] != '\0') { rule[n] = key[n]; n++; } rule[n] = '\0'; for (i = 0; i < alpha.length(); i++) { flag = 1; for (j = 0; j < key.length(); j++) { if (alpha[i] == key[j] || alpha[i] == 'j') { //i,j占据同一个字符 flag = 0; break; } } if (flag) rule[n++] = alpha[i]; } rule[n] = '\0'; // 组建 matrix key 并打印到屏幕 cout << endl << " matrix key" << endl << endl; k = 0; for (i = 0; i < 5; i++) { cout << " "; for (j = 0; j < 5; j++) { matrix[i][j] = rule[k]; cout << " " << rule[k]; k++; } cout << endl; } cout << endl << endl; return matrix; } //Playfair cipher 处理输入的明文/密文，将格式一致化 char *strtem(string st,char tem[50]) { int i = 0, j = 0; int flag = 0; //两两组合配对，检查每组元素是否相同，若相同，则添加元素'q' for (i = 0; i < st.length(); i++) { if (st[i] == 'j') { //字母j用字母i替代 tem[i] = 'i'; continue; } tem[i] = st[i]; } tem[i] = '\0'; for (i = 0; i < strlen(tem) - 1; i++) { if ((i % 2 == 0) && (tem[i] == tem[i + 1])) { //检测分组元素 for (j = strlen(tem) - 1; j >= i; j--) { tem[j + 1] = tem[j]; } tem[i + 1] = 'q'; } } //若长度为奇数，则在末尾添加元素'q'，使其成为偶数 if ((strlen(tem) % 2 != 0) && (tem[strlen(tem) - 1] == 'q')) { cout << "Error!Please choose another encryption algorithm!" << endl; exit(-1); } if ((strlen(tem) % 2 != 0) && (tem[strlen(tem) - 1] != 'q')) { tem[strlen(tem)] = 'q'; } tem[strlen(tem)] = '\0'; return tem; } int main(){ int i = 0, j = 0, k = 0, n = 0, m = 0; int flag = 0; int flag1, flag2, flag3, flag4; char(*matrix)[5]; char matrix1[5][5] = { 0 }; char plain[20][2] = { 0 }; char tem[50] = { 0 }; string st; do { fflush(stdin); cout << "-------------Playfair cipher(Encryption)------------" << endl; cout << " the null letter is 'q' " << endl; cout << "Please enter the plaintext:"; cin >> st; flag = Check(st); } while (flag); strtem(st, tem); matrix = matrixkey(matrix1); //将一维数组转化为二维数组，便于加密 for (i = 0; i < strlen(tem) / 2; i++) { for (j = 0; j < 2; j++) { plain[i][j] = tem[k]; k++; } } //以下为加密 flag = i; cout << "CipherText:"; for (i = 0; i < flag; i++) { j = 0; for (m = 0; m < 5; m++) { for (n = 0; n < 5; n++) { j = 0; if (matrix[m][n] == plain[i][j]) { flag1 = m; flag2 = n; } if (matrix[m][n] == plain[i][(j + 1)]) { flag3 = m; flag4 = n; } } } if (flag1 == flag3) { cout << matrix[flag1][((flag2 + 1) % 5)] << matrix[flag3][((flag4 + 1) % 5)]; } else if (flag2 == flag4) { cout << matrix[((flag1 + 1) % 5)][flag2] << matrix[((flag3 + 1) % 5)][flag4]; } else { cout << matrix[flag1][flag4] << matrix[flag3][flag2]; } } cout << endl << endl; return 0; } |
解密代码实现：
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#include <iostream> #include <string> #include <string.h> #include <unistd.h> using namespace std; int Check(string s) { //检查输入的字符串是否为纯英文 int i = 0; while (s[i] != '\0') { if (!((s[i] >= 'a'&&s[i] <= 'z') || (s[i] >= 'A'&&s[i] <= 'Z'))) { cout << "Error!Please enter again!" << endl; return 1; } i++; } return 0; } //Playfair cipher构造matrix key char(*matrixkey(char(&matrix)[5][5]))[5]{ int i = 0,j = 0,k = 0,n = 0; string keyword; int flag = 0; string key(20, '\0'); string rule(50, '\0'); string alpha("abcdefghijklmnopqrstuvwxyz"); do { //输入keyword fflush(stdin); cout << "select a keyword:"; cin >> keyword; flag = Check(keyword); } while (flag); for (i = 0; i < keyword.length(); i++) { //提取key flag = 1; if (keyword[i] == 'j') keyword[i] = i; for (j = 0; j < i; j++) { if (key[j] == keyword[i]) flag = 0; } if (flag) key[k++] = keyword[i]; } key[k] = '\0'; //组合对应表 while (key[n] != '\0') { rule[n] = key[n]; n++; } rule[n] = '\0'; for (i = 0; i < alpha.length(); i++) { flag = 1; for (j = 0; j < key.length(); j++) { if (alpha[i] == key[j] || alpha[i] == 'j') { //i,j占据同一个字符 flag = 0; break; } } if (flag) rule[n++] = alpha[i]; } rule[n] = '\0'; // 组建 matrix key 并打印到屏幕 cout << endl << " matrix key" << endl << endl; k = 0; for (i = 0; i < 5; i++) { cout << " "; for (j = 0; j < 5; j++) { matrix[i][j] = rule[k]; cout << " " << rule[k]; k++; } cout << endl; } cout << endl << endl; return matrix; } //Playfair cipher 处理输入的明文/密文，将格式一致化 char *strtem(string st,char tem[50]) { int i = 0, j = 0; int flag = 0; //两两组合配对，检查每组元素是否相同，若相同，则添加元素'q' for (i = 0; i < st.length(); i++) { if (st[i] == 'j') { //字母j用字母i替代 tem[i] = 'i'; continue; } tem[i] = st[i]; } tem[i] = '\0'; for (i = 0; i < strlen(tem) - 1; i++) { if ((i % 2 == 0) && (tem[i] == tem[i + 1])) { //检测分组元素 for (j = strlen(tem) - 1; j >= i; j--) { tem[j + 1] = tem[j]; } tem[i + 1] = 'q'; } } //若长度为奇数，则在末尾添加元素'q'，使其成为偶数 if ((strlen(tem) % 2 != 0) && (tem[strlen(tem) - 1] == 'q')) { cout << "Error!Please choose another encryption algorithm!" << endl; exit(-1); } if ((strlen(tem) % 2 != 0) && (tem[strlen(tem) - 1] != 'q')) { tem[strlen(tem)] = 'q'; } tem[strlen(tem)] = '\0'; return tem; } int main(){ int i = 0, j = 0, k = 0, n = 0, m = 0; int flag = 0; int flag1, flag2, flag3, flag4; char(*matrix)[5]; char matrix1[5][5] = { 0 }; char plain[20][2] = { 0 }; char tem[50] = { 0 }; string st; do { fflush(stdin); cout << "-------------Playfair cipher(decryption)------------" << endl; cout << "Please enter the ciphertext:"; cin >> st; if ((st.length() % 2) != 0) { cout << "Error!There must be even number of characters in the ciphertext!Please enter again!" << endl; exit(-1); } flag = Check(st); } while (flag); strtem(st, tem); matrix = matrixkey(matrix1); //将一维数组转化为二维数组，便于解密 for (i = 0; i < strlen(tem) / 2; i++) { for (j = 0; j < 2; j++) { plain[i][j] = tem[k]; k++; } } //以下为解密 flag = i; cout << "PlainText:"; for (i = 0; i < flag; i++) { j = 0; for (m = 0; m < 5; m++) { for (n = 0; n < 5; n++) { j = 0; if (matrix[m][n] == plain[i][j]) { flag1 = m; flag2 = n; } if (matrix[m][n] == plain[i][(j + 1)]) { flag3 = m; flag4 = n; } } } //解密关键代码 if (flag1 == flag3) { cout << matrix[flag1][((flag2 + 4) % 5)] << matrix[flag3][((flag4 + 4) % 5)]; } else if (flag2 == flag4) { cout << matrix[((flag1 + 4) % 5)][flag2] << matrix[((flag3 + 4) % 5)][flag4]; } else { cout << matrix[flag1][flag4] << matrix[flag3][flag2]; } } cout << endl << endl; return 0; } |
（编译运行环境：g++ [Debian 7.3.0-19] 7.3.0）
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