restore crypto functions from

2024-07-21 02:58:59 +02:00
parent d8be4676d0
commit c45f14c240
1 changed files with 115 additions and 0 deletions
@@ -0,0 +1,115 @@
+const IV_SIZE = 12;
+const ENCRYPTION_ALG = "AES-GCM";
+
+// minimal
+export async function encryptString(
+  plaintext: string,
+  passphrase: string
+): Promise<string> {
+  if (!window.crypto.subtle) return plaintext;
+
+  const iv = generateIV();
+  const key = await importKey(passphrase, "encrypt");
+  const encryptedArray = await encrypt(iv, key, plaintext);
+
+  const encryptionData = {
+    iv: uInt8ToArray(iv),
+    encryptedArray: uInt8ToArray(encryptedArray),
+  };
+  return btoa(JSON.stringify(encryptionData));
+}
+
+export async function decryptString(
+  cyphertext: string,
+  passphrase: string
+): Promise<string> {
+  try {
+    const encrypionData = JSON.parse(atob(cyphertext));
+    const iv = arrayToUint8(encrypionData.iv);
+    const encryptedArray = arrayToUint8(encrypionData.encryptedArray);
+
+    const key = await importKey(passphrase, "decrypt");
+    return await decrypt(iv, key, encryptedArray);
+  } catch {
+    return cyphertext;
+  }
+}
+
+// process
+export function encode(string: string): Uint8Array {
+  return new TextEncoder().encode(string);
+}
+
+export function decode(array: Uint8Array): string {
+  return new TextDecoder("utf-8").decode(array);
+}
+
+export async function encrypt(
+  iv: Uint8Array,
+  key: CryptoKey,
+  message: string
+): Promise<Uint8Array> {
+  const arrayBuffer = await window.crypto.subtle.encrypt(
+    { name: ENCRYPTION_ALG, iv },
+    key,
+    encode(message)
+  );
+  return new Uint8Array(arrayBuffer);
+}
+
+export async function decrypt(
+  iv: Uint8Array,
+  key: CryptoKey,
+  cyphertext: Uint8Array
+): Promise<string> {
+  const arrayBuffer = await crypto.subtle.decrypt(
+    { name: ENCRYPTION_ALG, iv },
+    key,
+    cyphertext
+  );
+  return arrayBufferToString(arrayBuffer);
+}
+
+export async function hash(encoded: Uint8Array): Promise<ArrayBuffer> {
+  return await crypto.subtle.digest("SHA-256", encoded);
+}
+
+// iv
+export function generateIV(): Uint8Array {
+  return crypto.getRandomValues(new Uint8Array(IV_SIZE));
+}
+
+export function splitMergedString(mergedString: string): [Uint8Array, string] {
+  const iv = mergedString.slice(0, IV_SIZE);
+  const encryptedString = mergedString.slice(IV_SIZE);
+
+  return [JSON.parse(iv), encryptedString];
+}
+
+// key
+export async function importKey(
+  passphrase: string,
+  purpose: "encrypt" | "decrypt"
+): Promise<CryptoKey> {
+  return await crypto.subtle.importKey(
+    "raw",
+    await hash(encode(passphrase)),
+    { name: ENCRYPTION_ALG },
+    false,
+    [purpose]
+  );
+}
+
+// conversion
+export function arrayBufferToString(arrayBuffer: ArrayBuffer): string {
+  const uInt8Array = new Uint8Array(arrayBuffer);
+  return decode(uInt8Array);
+}
+
+export function uInt8ToArray(uInt8Array: Uint8Array): number[] {
+  return Array.from(uInt8Array);
+}
+
+export function arrayToUint8(array: number[]): Uint8Array {
+  return new Uint8Array(array);
+}