非常簡單的消息編碼方式,僅僅是將字母后移3位,而X Y Z右移就回到A B C.
加密的話就是簡單的加三取模即可;解密就是其反過程。
C++實現如下:
#include#include#includeusing namespace std;
string nencrypted = { "Things are not always what they see" };
string ncrypted;
void encrypt(string &unencrypted,string &encrypted) {
encrypted.resize(unencrypted.size());
for (int i = 0;i < unencrypted.size();i++) {
if ((int)unencrypted[i]>64 && (int)unencrypted[i] < 91) {
encrypted[i] = (char)((((int)unencrypted[i] - 65 + 3) % 26) + 65);//減去65+3取模可得到後移三位的ascii(大寫)
}
else if ((int)unencrypted[i] > 96 && (int)unencrypted[i] < 123) {
encrypted[i] = (char)((((int)unencrypted[i] - 97 + 3) % 26) + 97);//減去97+3取模可得到後移三位的ascii(小寫)
}
else {
encrypted[i] = unencrypted[i];
}
}
}
void decrypt(string &encrypted, string &decrypted) {
decrypted.resize(encrypted.size());
for (int i = 0;i < encrypted.size();i++) {
if ((int)encrypted[i]>64 && (int)encrypted[i] < 91) {
decrypted[i] = (char)((((int)encrypted[i] - 65 - 3 + 26) % 26) + 65);//減去65-3取模可得到前移三位的ascii(大寫) //加26使其非負
}
else if ((int)encrypted[i] > 96 && (int)encrypted[i] < 123) {
decrypted[i] = (char)((((int)encrypted[i] - 97 - 3 + 26) % 26) + 97);//減去97-3取模可得到前移三位的ascii(小寫)//加26使其非負
}
else {
decrypted[i] = encrypted[i];
}
}
}
int main() {
encrypt(nencrypted, ncrypted);
cout << ncrypted << endl;
decrypt(ncrypted, nencrypted);
cout << nencrypted << endl;
return 0;
}