리다이렉트 경로 처리, 파일 정보 변환, 상태 표시 UI 등 중복된 코드를 통합하고 모듈 간 순환 의존성 및 계층 위반 해소

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/shared/crypto/aes.ts

@@ -1,4 +1,3 @@
-import { AES_GCM_IV_SIZE } from "#lib/shared/format/index.ts";
 import {
   encodeString,
   decodeString,
@@ -7,6 +6,9 @@ import {
   concatenateBuffers,
 } from "./encoding.ts";
 
+export const AES_GCM_IV_SIZE = 12;
+export const AES_GCM_TAG_SIZE = 16;
+
 export const generateMasterKey = async () => {
   return {
     masterKey: await crypto.subtle.generateKey(
@@ -44,10 +46,12 @@ export const makeAESKeyNonextractable = async (key: CryptoKey) => {
   );
 };
 
-export const wrapDataKey = async (dataKey: CryptoKey, masterKey: CryptoKey) => {
-  return encodeToBase64(await crypto.subtle.wrapKey("raw", dataKey, masterKey, "AES-KW"));
+const wrapKey = async (key: CryptoKey, masterKey: CryptoKey) => {
+  return encodeToBase64(await crypto.subtle.wrapKey("raw", key, masterKey, "AES-KW"));
 };
 
+export const wrapDataKey = wrapKey;
+
 export const unwrapDataKey = async (dataKeyWrapped: string, masterKey: CryptoKey) => {
   return {
     dataKey: await crypto.subtle.unwrapKey(
@@ -62,9 +66,7 @@ export const unwrapDataKey = async (dataKeyWrapped: string, masterKey: CryptoKey
   };
 };
 
-export const wrapHmacSecret = async (hmacSecret: CryptoKey, masterKey: CryptoKey) => {
-  return encodeToBase64(await crypto.subtle.wrapKey("raw", hmacSecret, masterKey, "AES-KW"));
-};
+export const wrapHmacSecret = wrapKey;
 
 export const unwrapHmacSecret = async (hmacSecretWrapped: string, masterKey: CryptoKey) => {
   return {
@@ -84,7 +86,7 @@ export const unwrapHmacSecret = async (hmacSecretWrapped: string, masterKey: Cry
 };
 
 export const encryptData = async (data: BufferSource, dataKey: CryptoKey) => {
-  const iv = crypto.getRandomValues(new Uint8Array(12));
+  const iv = crypto.getRandomValues(new Uint8Array(AES_GCM_IV_SIZE));
   const ciphertext = await crypto.subtle.encrypt(
     {
       name: "AES-GCM",

src/lib/shared/crypto/rsa.ts

@@ -166,15 +166,21 @@ export const verifySignatureRSA = async (
   );
 };
 
+// The message signed by clients to prove the integrity of the wrapped master key. Also verified
+// by the server, so it must not be changed.
+export const serializeMasterKeyWrapped = (masterKeyWrapped: string, masterKeyVersion: number) => {
+  return JSON.stringify({
+    version: masterKeyVersion,
+    key: masterKeyWrapped,
+  });
+};
+
 export const signMasterKeyWrapped = async (
   masterKeyWrapped: string,
   masterKeyVersion: number,
   signKey: CryptoKey,
 ) => {
-  const serialized = JSON.stringify({
-    version: masterKeyVersion,
-    key: masterKeyWrapped,
-  });
+  const serialized = serializeMasterKeyWrapped(masterKeyWrapped, masterKeyVersion);
   return encodeToBase64(await signMessageRSA(encodeString(serialized), signKey));
 };
 
@@ -184,10 +190,7 @@ export const verifyMasterKeyWrapped = async (
   masterKeyWrappedSig: string,
   verifyKey: CryptoKey,
 ) => {
-  const serialized = JSON.stringify({
-    version: masterKeyVersion,
-    key: masterKeyWrapped,
-  });
+  const serialized = serializeMasterKeyWrapped(masterKeyWrapped, masterKeyVersion);
   return await verifySignatureRSA(
     encodeString(serialized),
     decodeFromBase64(masterKeyWrappedSig),