N个整数(数的大小为0-255)的序列,把它们加密为K个整数(数的大小为0-255).再将K个整数顺序随机打乱,使得可以从这乱序的K个整数中解码出原序列。设计加密解密算法,且要求K<=15*N.
如果是:
- N<=16,要求K<=16*N.
- N<=16,要求K<=10*N.
- N<=64,要求K<=15*N.
#include <iostream> using namespace std; void printArray(int* arr, int len) { if (!arr) { return; } for (int i = 0; i < len; ++i) { cout << arr[i] << " "; } cout << endl; } int cmp(const void *a, const void *b) { int aa = (*(const int*) a) >> 4; int bb = (*(const int*) b) >> 4; return aa - bb; } int cmp1(const void *a, const void *b) { int aa = (*(const int*) a) >> 2; int bb = (*(const int*) b) >> 2; return aa - bb; } void disorder(int* arr, int len) { srand((int) time(NULL)); for (int i = 0; i < len; i++) { int tmp = rand() % len; swap(arr[i], arr[tmp]); } } int* encrypt1(int* arr, int len, int k) { int id = 0; int* encryptArr = new int[k * len]; memset(encryptArr, 0, sizeof(int) * k * len); for (int i = 0; i < len; ++i) { int index = (i << 4); int prev = arr[i] >> 4; int last = arr[i] & 15; for (int j = 0; j < k - 8; ++j, id++) { encryptArr[id] = index | prev; } for (int j = 0; j < 8; ++j, id++) { encryptArr[id] = index | last; } } // printArray(encryptArr, k * len); disorder(encryptArr, k * len); return encryptArr; } int* encrypt2(int* arr, int len, int k) { int id = 0; int* encryptArr = new int[k * len]; memset(encryptArr, 0, sizeof(int) * k * len); for (int i = 0; i < len; ++i) { int index = (i << 2); int data1 = arr[i] >> 6; int data2 = (arr[i] >> 4) & 3; int data3 = (arr[i] >> 2) & 3; int data4 = arr[i] & 3; encryptArr[id++] = index | data1; for (int j = 0; j < 2; ++j, id++) { encryptArr[id] = index | data2; } for (int j = 0; j < 4; ++j, id++) { encryptArr[id] = index | data3; } for (int j = 0; j < 8; ++j, id++) { encryptArr[id] = index | data4; } } // printArray(encryptArr, k * len); disorder(encryptArr, k * len); return encryptArr; } int* decrypt1(int* encryptArr, int len, int k) { qsort(encryptArr, k * len, sizeof(int), cmp); // printArray(encryptArr, k * len); int* decryptArr = new int[len]; memset(decryptArr, 0, sizeof(int) * len); int prev = 0; int last = 0; int count1 = 0; int count2 = 0; int index = 0; for (int i = 0; i < k * len; i += k) { prev = encryptArr[i]; count1 = 1; count2 = 0; for (int j = i + 1; j < i + k; ++j) { if (prev == encryptArr[j]) { count1++; } else { last = encryptArr[j]; count2++; } } if (count1 > k - 8) { if (count1 == k) { //加密前prev,last相同 last = prev; } swap(last, prev); } else if (count2 > k - 8) { if (count2 == k) { prev = last; } } prev &= 15; last &= 15; prev <<= 4; decryptArr[index++] = prev | last; } return decryptArr; } int* decrypt2(int* encryptArr, int len, int k) { qsort(encryptArr, k * len, sizeof(int), cmp1); // printArray(encryptArr, k * len); int* decryptArr = new int[len]; memset(decryptArr, 0, sizeof(int) * len); int* data = new int[4]; int* count = new int[4]; int index = 0; int id = 1; for (int i = 0; i < k * len; i += k) { memset(data, -1, 4 * sizeof(int)); memset(count, 0, 4 * sizeof(int)); data[0] = encryptArr[i]; count[0] = 1; id = 1; for (int j = i + 1; j < i + k; ++j) { if (encryptArr[j] == data[0]) { count[0]++; } else if (encryptArr[j] == data[1]) { count[1]++; } else if (encryptArr[j] == data[2]) { count[2]++; } else if (encryptArr[j] == data[3]) { count[3]++; } else if (id < 4) { data[id] = encryptArr[j]; count[id]++; id++; } } int data1 = -1; int data2 = -1; int data3 = -1; int data4 = -1; for (int i = 0; i < 4; ++i) { if (!count[i]) { break; } switch (count[i]) { case 1: data1 = data[i] & 3; break; case 2: data2 = data[i] & 3; break; case 4: data3 = data[i] & 3; break; case 8: data4 = data[i] & 3; break; case 3: data1 = data2 = data[i] & 3; break; case 5: data1 = data3 = data[i] & 3; break; case 9: data1 = data4 = data[i] & 3; break; case 6: data2 = data3 = data[i] & 3; break; case 10: data2 = data4 = data[i] & 3; break; case 12: data3 = data4 = data[i] & 3; break; case 7: data1 = data2 = data3 = data[i] & 3; break; case 11: data1 = data2 = data4 = data[i] & 3; break; case 13: data1 = data3 = data4 = data[i] & 3; break; case 14: data2 = data3 = data4 = data[i] & 3; break; } } decryptArr[index] |= data1 << 6; decryptArr[index] |= data2 << 4; decryptArr[index] |= data3 << 2; decryptArr[index] |= data4; index++; } return decryptArr; } int* encryptChoice(int* arr, int len, int n, int k) { int* encryptArr = NULL; if (n == 16) { if (len > n) { return NULL; } if (k == 16) { k = 12; encryptArr = encrypt1(arr, len, k); } else if (k == 10) { encryptArr = encrypt1(arr, len, k); } } else if (n == 64 && k == 15) { encryptArr = encrypt2(arr, len, k); } if (encryptArr) { cout << "n,k: " << n << "," << k << endl; cout << "加密数组:" << endl; printArray(encryptArr, k * len); } return encryptArr; } void decryptChoice(int* encryptArr, int len, int n, int k) { int* decryptArr = NULL; if (n == 16) { //int 是32bit if (len > n) { return; } if (k == 16) { k = 12; decryptArr = decrypt1(encryptArr, len, k); } else if (k == 10) { decryptArr = decrypt1(encryptArr, len, k); } } else if (n == 64 && k == 15) { decryptArr = decrypt2(encryptArr, len, k); } if (decryptArr) { cout << "解密数组:" << endl; printArray(decryptArr, len); } } int main() { int arr1[] = { 12, 20, 51, 4, 7, 48, 32, 13, 41, 35, 44, 67, 55, 34, 54, 63 }; int len = sizeof(arr1) / sizeof(int); int k = 16; int n = 16; int* encryptArr = NULL; encryptArr = encryptChoice(arr1, len, n, k); decryptChoice(encryptArr, len, n, k); k = 10; encryptArr = encryptChoice(arr1, len, n, k); decryptChoice(encryptArr, len, n, k); k = 15; n = 64; encryptArr = encryptChoice(arr1, len, n, k); decryptChoice(encryptArr, len, n, k); return 0; }