Szyfr Trithemius'a

Opis problemu

Szyfrowanie

Implementacja

#include <iostream>

using namespace std;

string encryptTrithemius(string message) {
    string result = "";
    char encrypted;
    int k = 0;

    for(char letter : message) {
        encrypted = letter + k;
        if(encrypted > 'z') {
            encrypted = encrypted - 'z' + 'a' - 1;
        }

        result += encrypted;
        k += 1;
        k %= 26;
    }

    return result;
}

int main() {
    string message = "computerscience";

    string encrypted = encryptTrithemius(message);

    cout << encrypted << endl;

    return 0;
}

Deszyfrowanie

Implementacja

#include <iostream>

using namespace std;

string decryptTrithemius(string encrypted) {
    string result = "";
    char decrypted;
    int k = 0;

    for(char letter : encrypted) {
        decrypted = letter - k;
        if(decrypted < 'a') {
            decrypted = 'z' - ('a' - decrypted - 1);
        }

        result += decrypted;
        k += 1;
        k %= 26;
    }

    return result;
}

int main() {
    string encrypted = "cposyykyblspzps";

    string decrypted = decryptTrithemius(encrypted);

    cout << decrypted << endl;

    return 0;
}