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import { crypto } from "https://deno.land/std@0.149.0/crypto/mod.ts";import {  decode as bd,  encode as be,} from "https://deno.land/std@0.149.0/encoding/base64.ts";
// Helper functions to encrypt / decrypt using AES with default config in CryptoJS
// NOTE: Encryption will be using SHA-384 instead of MD5 in Key Derivation, so it can't be decrypted using CryptoJS// Decryption will try MD5 after SHA-384 generated key fails, so it can decrypt cipher text encrypted by CryptoJS
// For CryptoJS cipher text:// It has a constant header for the first 8 byte.// It has the salt in the second 8 byte.// The rest is the cipher text.// +----------+----------+-----------------+// | Salted__ |  <salt>  |  <cipherText>   |// +----------+----------+-----------------+// |  64 bit  |  64 bit  | variable length |// +----------+----------+-----------------+
// size in byte, same as CryptoJS's default.const HEADER_SIZE = 8;const SALT_SIZE = 8;const KEY_SIZE = 32;const IV_SIZE = 16;
export const encryptCryptoJSAES = async (  plainText: string,  passphrase: string,  iterations = 1,): Promise<string> => {  const salt = new Uint8Array(SALT_SIZE);  crypto.getRandomValues(salt);
  const { key, iv } = await EVPKDF(    new TextEncoder().encode(passphrase),    salt,    "SHA-384",    iterations,  );
  const cipherText = await crypto.subtle.encrypt(    { name: "AES-CBC", iv },    key,    new TextEncoder().encode(plainText),  );
  // get the CryptoJS style cipher text.  // "Salted__" + key + encryptedText  return be(    concatUint8Array(      new TextEncoder().encode("Salted__"),      salt,      new Uint8Array(cipherText),    ),  );};
// decrypt cipher text generated by default CryptoJS AES.// cipher text should be in base64 (the default of CryptoJS's toString())export const decryptCryptoJSAES = async (  cipherTextBase64: string,  passphrase: string,  iterations = 1,): Promise<string> => {  const cipherText = bd(cipherTextBase64);
  const { salt, body } = parseCryptoJSCipherText(cipherText);
  const { key, iv } = await EVPKDF(    new TextEncoder().encode(passphrase),    salt,    "SHA-384",    iterations,  );
  let plainText: ArrayBuffer;  try {    plainText = await crypto.subtle.decrypt(      { name: "AES-CBC", iv },      key,      body,    );  } catch (_) {    const { key, iv } = await EVPKDF(      new TextEncoder().encode(passphrase),      salt,      "MD5",      iterations,    );
    plainText = await crypto.subtle.decrypt(      { name: "AES-CBC", iv },      key,      body,    );  }
  return new TextDecoder().decode(plainText);};
const parseCryptoJSCipherText = (cipherText: Uint8Array): {  salt: Uint8Array;  body: Uint8Array;} => ({  salt: cipherText.subarray(HEADER_SIZE, HEADER_SIZE + SALT_SIZE),  body: cipherText.subarray(HEADER_SIZE + SALT_SIZE, cipherText.length),});
// a customed version of EVPKDF using sha-384 instead of md5.const EVPKDF = async (  passphrase: Uint8Array,  salt: Uint8Array,  algorithm: "SHA-384" | "MD5",  iterations: number,): Promise<{ key: CryptoKey; iv: Uint8Array }> => {  let rawKey = new Uint8Array();  let block = new Uint8Array();
  while (rawKey.byteLength < KEY_SIZE + IV_SIZE) {    let buffer = await crypto.subtle.digest(      algorithm,      concatUint8Array(block, passphrase, salt),    );
    for (let i = 1; i < iterations; i++) {      buffer = await crypto.subtle.digest(        algorithm,        buffer,      );    }
    block = new Uint8Array(buffer);    rawKey = concatUint8Array(rawKey, block);  }
  return {    key: await crypto.subtle.importKey(      "raw",      rawKey.subarray(0, KEY_SIZE),      "AES-CBC",      false,      ["encrypt", "decrypt"],    ),    iv: rawKey.subarray(KEY_SIZE, rawKey.length),  };};
const concatUint8Array = (...arrays: Uint8Array[]): Uint8Array => {  const size = arrays.reduce((len, array) => len + array.length, 0);
  const merged = new Uint8Array(size);
  let mergedLen = 0;  for (const array of arrays) {    merged.set(array, mergedLen);    mergedLen += array.length;  }
  return merged;};