Add safety with nulls

src/pwd-box.ts

@@ -11,21 +11,31 @@ export default class PwdBox {
     private readonly salt: Uint8Array
   ) {}
 
-  private static async derive(pwd: string, salt: Uint8Array, context?: string): Promise<CryptoKey> {
-    const k = await pbkdf(salt, pwd) // TODO : null
-    return await hkdf(k, Usage.box, context) as CryptoKey // TODO : null
+  private static async derive(pwd: string, salt: Uint8Array, context?: string): Promise<CryptoKey | null> {
+    const k = await pbkdf(salt, pwd)
+    if (k === null) return null
+    return await hkdf(k, Usage.box, context) as CryptoKey
   }
 
-  public static async encrypt(data: Uint8Array, pwd: string, context?: string): Promise<PwdBox> {
+  public static async encrypt(data: Uint8Array, pwd: string, context?: string): Promise<PwdBox | null> {
     log.trace('encrypt')
+
     const salt = crypto.getRandomValues(new Uint8Array(16))
-    const k = await PwdBox.derive(pwd, salt, context) // TODO : null
-    const box = await SecretBox.encrypt(data, k) // TODO : null
+
+    const k = await PwdBox.derive(pwd, salt, context)
+    if (k === null) return null
+
+    const box = await SecretBox.encrypt(data, k)
+    if (box === null) return null
+
     return new PwdBox(box, salt)
   }
   public async decrypt(pwd: string, context?: string): Promise<Uint8Array | null> {
     log.trace('decrypt')
-    const k = await PwdBox.derive(pwd, this.salt, context) // TODO : null
+
+    const k = await PwdBox.derive(pwd, this.salt, context)
+    if (k === null) return null
+
     return await this.box.decrypt(k)
   }