Asal Sayıları Kullanarak Mesaj Şifreleme ve Çözme

Kod 
Yığını:
import java.util.*;

public class Encryption {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String text = input.nextLine();
        System.out.println(textEncryption(text));
    }

    public static String textEncryption(String text) {
        int[] primeArray=new int[text.length()];
        primeNumbers(primeArray);

        StringBuilder newText = new StringBuilder();
        int character;

        for(int a=0;a<text.length();a++){
            character=text.charAt(a);
            if(character==32)
                newText.append((char) character);
            else if(character>=33 && character<=64){
                newText.append((char) (((character)+primeArray[a])%32+65));
            }
            else if(character>=65 && character<=96){
                newText.append((char) (((character)+primeArray[a])%32+33));
            }
            else
                newText.append((char) (((character)+primeArray[a])%26+97));
        }

        return newText.toString();
    }

    public static void primeNumbers(int[] array) {
        boolean prime=true;
        array[0]=2;
        int ordinaryNumber=3, numberOfElements=1;
        for(int a=1;a<array.length;){
            prime=true;
            for(int b=0;b<numberOfElements;b++) {
                if (ordinaryNumber % array[b]==0){
                    prime=false;
                    break;
                }
            }
            if(prime) {
                array[a]=ordinaryNumber;
                numberOfElements++;
                a++;
            }
            ordinaryNumber++;
        }
    }
}

https://onecompiler.com/java/3wpb42p7p

Kod 
Yığını:
import java.util.*;

public class Decryption {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String text = input.nextLine();
        solution(text);
    }
    public static void solution(String text) {
        int[] primeArray=new int[text.length()];
        primeNumbers(primeArray);
        StringBuilder newText = new StringBuilder();
        int character;
        for(int a=0;a<text.length();a++){
            character=text.charAt(a);
            if(character==32)
                newText.append( (char) 32 );
            else if(character>=33 && character<=64){
                character -= 65;
                character -= primeArray[a] % 32;
                while (character < 65)
                    character += 32;
                newText.append( (char) character );
            }
            else if(character>=65 && character<=96){
                character -= 33;
                character -= primeArray[a] % 32;
                while (character < 33)
                    character += 32;
                newText.append( (char) character );
            }
            else {
                character -= 97;
                character -= primeArray[a] % 26;
                while (character < 97)
                    character += 26;
                newText.append( (char) character );
            }
        }
        System.out.println(newText.toString());
    }

    public static void primeNumbers(int[] array) {
        boolean prime=true;
        array[0]=2;
        int ordinaryNumber=3, numberOfElements=1;
        for(int a=1;a<array.length;){
            prime=true;
            for(int b=0;b<numberOfElements;b++) {
                if (ordinaryNumber % array[b]==0){
                    prime=false;
                    break;
                }
            }
            if(prime) {
                array[a]=ordinaryNumber;
                numberOfElements++;
                a++;
            }
            ordinaryNumber++;
        }
    }
}

https://onecompiler.com/java/3wpb42p7p

Dostum java pratiği için güzel bir uygulama olmuş ama şifreleme tekniği olarak 2000 senelik sezar tekniğinden bir farkı yok malesef.

https://en.wikipedia.org/wiki/Caesar_cipher

Asal sayıların gerçekten kullanıldığı bir şifreleme yöntemi istiyorsan RSA yi incele.

https://en.wikipedia.org/wiki/RSA_(cryptosystem)

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