108 lines
2.5 KiB
JavaScript
108 lines
2.5 KiB
JavaScript
const ALGORITHM_NAME = "AES-GCM";
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const ALGORITHM_LENGTH = 256;
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const IV_LENGTH = 16;
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const TEXT_ENCODER = new TextEncoder();
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const TEXT_DECODER = new TextDecoder();
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/** Coverts an ArrayBuffer into a Base64 encoded string
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* @param {ArrayBuffer} buffer
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* @returns {string}
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*/
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function bufferToBase64(buffer) {
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let binary = "";
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const bytes = new Uint8Array(buffer);
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const len = bytes.byteLength;
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for (let i = 0; i < len; i++) {
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binary += String.fromCharCode(bytes[i]);
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}
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return btoa(binary);
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}
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/** Converts a Base64 encoded string into an ArrayBuffer
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* @param {string} base64
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* @returns {ArrayBuffer}
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*/
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function base64ToBuffer(base64) {
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const binaryString = atob(base64);
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const len = binaryString.length;
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const bytes = new Uint8Array(len);
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for (let i = 0; i < len; i++) {
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bytes[i] = binaryString.charCodeAt(i);
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}
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return bytes.buffer;
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}
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/** Generates an key and encrypts "password" using it
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* @param {Promise<string>} password
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*/
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async function encryptPassword(password) {
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const iv = new Uint8Array(IV_LENGTH);
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window.crypto.getRandomValues(iv);
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const key = await window.crypto.subtle.generateKey(
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{
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name: ALGORITHM_NAME,
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length: ALGORITHM_LENGTH,
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},
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true,
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["encrypt", "decrypt"],
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);
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const encryptedPassword = await window.crypto.subtle.encrypt(
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{
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name: ALGORITHM_NAME,
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iv: iv,
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},
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key,
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TEXT_ENCODER.encode(password),
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);
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const exportedKey = await window.crypto.subtle.exportKey("raw", key);
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const encodedPassword = bufferToBase64(encryptedPassword);
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const encodedKey = bufferToBase64(exportedKey);
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const encodedIv = bufferToBase64(iv.buffer);
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return {
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password: encodedPassword,
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key: encodedKey,
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iv: encodedIv,
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};
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}
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/** Decodes to key and iv and decryptes the password
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* @param {string} password
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* @param {string} key
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* @param {string} iv
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* @returns {Promise<string>}
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*/
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async function decryptPassword(password, key, iv) {
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const decodedPassword = base64ToBuffer(password);
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const decodedKey = base64ToBuffer(key);
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const decodedIv = base64ToBuffer(iv);
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const cryptoKey = await window.crypto.subtle.importKey(
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"raw",
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decodedKey,
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{
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name: ALGORITHM_NAME,
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length: ALGORITHM_LENGTH,
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},
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true,
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["encrypt", "decrypt"],
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);
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const decryptedPassword = await window.crypto.subtle.decrypt(
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{
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name: ALGORITHM_NAME,
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iv: decodedIv,
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},
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cryptoKey,
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decodedPassword,
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);
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return TEXT_DECODER.decode(decryptedPassword);
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}
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