90 lines
3.2 KiB
JavaScript
90 lines
3.2 KiB
JavaScript
const CHARS = [
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'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
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'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
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'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
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'&', '$',
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];
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export const generatePad = (length) => {
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const pad = [];
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for (let i = 0; i < length; i++) {
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const letter = Math.floor(Math.random() * CHARS.length);
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pad.push(CHARS[letter]);
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}
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return pad;
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}
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const stripString = (string) => {
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return string.replace(/[\s]+/g, '&').replace(/[^a-zA-Z0-9\&]/g, '$');
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}
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export const encrypt = (string, pad = null) => {
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const strippedString = stripString(string).toUpperCase();
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pad = pad ? pad : generatePad(strippedString.length);
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return {
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oneTimePad: pad,
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encryptedMessage: pad.map((letter, index) => {
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const messageLetter = strippedString.charAt(index);
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const letterValue = messageLetter !== '' ? CHARS.indexOf(messageLetter) : CHARS.length - 1;
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const padValue = CHARS.indexOf(letter);
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return CHARS[(letterValue + padValue) % CHARS.length];
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}).join(''),
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};
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}
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export const decrypt = (string, pad) => {
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string = string.toUpperCase();
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return pad.map((letter, index) => {
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const letterValue = CHARS.indexOf(string.charAt(index));
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const padValue = CHARS.indexOf(letter);
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let charIndex = (letterValue - padValue);
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while (charIndex < 0) {charIndex += CHARS.length}
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return CHARS[charIndex % CHARS.length];
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}).join('').replace(/\&/g, ' ').replace(/\$/g, '-');
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}
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window.onload = () => {
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document.getElementById('encryptInput').onclick = () => {
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const error = document.getElementById('inputError');
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const input = document.getElementById('input').value;
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const inputPad = stripString(document.getElementById('inputPad').value).toUpperCase();
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const pad = inputPad !== '' ? inputPad.split('') : null;
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if (pad !== null && pad.length < input.length) {
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document.getElementById('inputPad').value = pad.join('');
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error.innerHTML = 'The pad must be at least as long as the input';
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} else {
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error.innerHTML = '';
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const encryption = encrypt(input, pad);
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document.getElementById('inputPad').value = encryption.oneTimePad.join('');
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document.getElementById('encrypted').innerHTML = encryption.encryptedMessage;
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}
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}
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document.getElementById('decryptInput').onclick = () => {
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const input = document.getElementById('encryptedInput').value;
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const pad = document.getElementById('encryptedInputPad').value.split('');
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const output = decrypt(input, pad);
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document.getElementById('decrypted').innerHTML = output;
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}
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document.getElementById('padLength').oninput = (event) => {
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const value = parseInt(event.target.value);
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if (value < 1) event.target.value = 1;
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}
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document.getElementById('generatePad').onclick = () => {
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const field = document.getElementById('padLength');
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if (field.value === '') {
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field.value = '10';
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}
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const length = parseInt(field.value, 10);
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const output = generatePad(length);
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document.getElementById('inputPad').value = output.join('');
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}
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document.getElementById('clearPad').onclick = () => {
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document.getElementById('padLength').value = '';
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document.getElementById('inputPad').value = '';
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}
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}
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