파일 다운로드 임시 구현

src/lib/modules/crypto/aes.ts

@@ -1,4 +1,4 @@
-import { encodeToBase64, decodeFromBase64 } from "./util";
+import { encodeString, decodeString, encodeToBase64, decodeFromBase64 } from "./util";
 
 export const generateMasterKey = async () => {
   return {
@@ -81,3 +81,12 @@ export const decryptData = async (ciphertext: BufferSource, iv: string, dataKey:
     ciphertext,
   );
 };
+
+export const encryptString = async (plaintext: string, dataKey: CryptoKey) => {
+  const { ciphertext, iv } = await encryptData(encodeString(plaintext), dataKey);
+  return { ciphertext: encodeToBase64(ciphertext), iv };
+};
+
+export const decryptString = async (ciphertext: string, iv: string, dataKey: CryptoKey) => {
+  return decodeString(await decryptData(decodeFromBase64(ciphertext), iv, dataKey));
+};

src/lib/modules/crypto/util.ts

@@ -1,3 +1,14 @@
+const textEncoder = new TextEncoder();
+const textDecoder = new TextDecoder();
+
+export const encodeString = (data: string) => {
+  return textEncoder.encode(data);
+};
+
+export const decodeString = (data: ArrayBuffer) => {
+  return textDecoder.decode(data);
+};
+
 export const encodeToBase64 = (data: ArrayBuffer) => {
   return btoa(String.fromCharCode(...new Uint8Array(data)));
 };

src/lib/services/file.ts

@@ -0,0 +1,10 @@
+import { unwrapDataKey, decryptString } from "$lib/modules/crypto";
+import type { FileInfoResponse } from "$lib/server/schemas";
+
+export const decryptFileMetadata = async (metadata: FileInfoResponse, masterKey: CryptoKey) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  return {
+    dataKey,
+    name: await decryptString(metadata.name, metadata.nameIv, dataKey),
+  };
+};