Encryption.java

//Made by Gregory Drapeau, began programing 5/4/2024 in NY, finished 7/13/2024 at YYC
//|E~[=Ej1l*l~k7mngo:[9o+~0$56~5E|P80r~:j~n5o]jlil7)0o1~,%75,=~V0/7.<1~=)99J.r,=~z%=/Z9 ,,~7<t~W:%QU=9|
import java.util.Scanner;
public class Encryption {
    public static String encrypt(String string, int key){
        string=crap(string, key);
        string=charChange(string);
        for(int i=0;i<3;i++){
            string = groups(string);
            string = rev(string);
        }
        string="|"+string+"|";
        return string;
    }
    public static String decrypt(String string, int key){
        string=string.substring(1,string.length()-1);
        for(int i=0;i<3;i++) {
            string = rev(string);
            string = groups(string);
        }
        string=charChange(string);
        string=deCrap(string, key);
        return string;
    }
    public static String groups(String string){
        String output="";
        for(int i=0;i<(string.length())/2;i++){
            output+=String.valueOf(string.charAt(i*2+1))+String.valueOf(string.charAt(i*2));
        }
        if(string.length()%2!=0){
            output+=String.valueOf(string.charAt(string.length()-1));
        }
        return output;
    }
    public static String rev(String string){
        String output="";
        for(int i=string.length();i>0;i--){
            output+=string.charAt(i-1);
        }
        return output;
    }
    public static String charChange(String string){
        String newString="";
        int high=0;
        int low=65536;
        boolean odd=false;
        for(int i=0;i<string.length();i++){
            high=Math.max(high, (int)(string.charAt(i)));
            low=Math.min(low, (int)(string.charAt(i)));
        }
        if((high-low)%2!=0&&string.charAt(0)!='!'){
            low++;
            odd=true;
        }
        int middle=(high+low)/2;
        if(string.charAt(0)=='!') {
            high--;
            string = string.substring(1);
        }
        for(int i=0;i<string.length();i++){
            int ascii=(int)string.charAt(i);
            char newChar=(char)(middle-(ascii-middle));
            newString+=String.valueOf(newChar);
        }
        if(odd){
            newString="!"+newString;
        }
        return newString;
    }
    public static String crap(String string, int key){
        int stringLength=string.length()/key;
        for(int i=1;i<=stringLength;i++){
            char extra=(char)((int)(Math.random()*95+32));
            string=string.substring(0,i*(key+1)-1)+String.valueOf(extra)+string.substring(i*(key+1)-1);
        }
        return string;
    }
    public static String deCrap(String string, int key){
        int stringLength=string.length()/(key+1);
        for(int i=1;i<=stringLength;i++){
            string=string.substring(0,i*key)+string.substring(i*key+1);
        }
        return string;
    }
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        System.out.println("Type \"en\" to encrypt a message or \"de\" to decrypt a message");
        String mode = scanner.nextLine().toLowerCase();
        while(mode.equals("de")||mode.equals("en")) {
            System.out.print("Encryption key: ");
            int key = scanner.nextInt();
            scanner.nextLine();
            System.out.print("Phrase: ");
            String phrase = scanner.nextLine();
            if(mode.equals("en")) {
                String encrypt = encrypt(phrase,key);
                System.out.println(encrypt);
            }else {
                String decrypt = decrypt(phrase,key);
                System.out.println(decrypt);
            }
            System.out.println("\nType \"en\" to encrypt a message or \"de\" to decrypt a message");
            mode=scanner.nextLine().toLowerCase();
        }
    }
}