在 JavaScript 中寻找凯撒的密码脚本我可以修改以允许所有（可键入的）ASCII 字符

Question

I've been working on a data encryption program in my spare time. I've added my own layer of encryption, and I'm attempting to add a modified Caesar's cipher that, when shifting, shifts spaces, numbers, and other characters from the ASCII characters list.

I've modified two scripts already:

• one from https://www.projectnayuki.io ,
• and the other from some GitHub page.

Neither works properly.

Text is the inputted characters, c is a single character in ASCII, result is the result.

 var result = "";
    for (var i = 0; i < text.length;) {
    var c = text.charCodeAt(i);
    if (32<=c&&c<=126){result+=String.fromCharCode((c-32+key)%94+32);}
      else throw("character not within range");i++};

I have modified this code so it uses special characters but when decrypting, if I have special characters and a key higher than about 20, characters go out of range and return blanks.

Answer 1

actually I've just checked your script and it works. I've put it inside a function:

const text = 'abcABC';
const key = 10;

function caesar(text, key) {
  var result = '';

  for (var i = 0; i < text.length; ) {
    var c = text.charCodeAt(i);
    if (32 <= c && c <= 126) {
      result += String.fromCharCode(((c - 32 + key) % 94) + 32);
    } else throw 'character not within range';
    i++;
  }

  return result;
}

const x = caesar(text, key);

console.log(x);  // -> klmKLM

const y = caesar(x, -key);

console.log(y);  // -> abcABC

Answer 2

Found my own fix,

var result = ``;
    for (var i = 0; i < text.length;) {
            var c = text.charCodeAt(i);
            for (var a = 0; a < key;){
                c=c-1;
                if (c<32){
                c=c+94;
                };
                a++;
                console.log(a);
            }
            result+=String.fromCharCode(c);
            i++;
    }

works perfectly and even supports multiline!