Implement pwd box

src/boxes/pwd.ts

@@ -1,17 +1,64 @@
-import type {Result} from 'result'
+import {Result} from 'result'
+import * as misc from 'misc'
+import {SecretBox} from './symmetric'
 
 export class PwdBox<T> {
-    public static encrypt<T>(pwd: string, data: Uint8Array) : PwdBox<T> {
-        throw "todo"
+    private readonly secret_box: SecretBox<T>
+    private readonly salt: Uint8Array
+
+    private constructor(secret_box: SecretBox<T>, salt: Uint8Array) {
+        this.secret_box = secret_box
+        this.salt = salt
     }
-    public decrypt(pwd: string) : Result<Uint8Array> {
-        throw "todo"
+
+    public static async encrypt<T>(pwd: string, data: Uint8Array): Promise<PwdBox<T>> {
+        const salt = crypto.getRandomValues(new Uint8Array(18))
+        const key = await PwdBox.gen_key(pwd, salt)
+
+        const box = (await SecretBox.encrypt<T>(key, data)).unwrap() // I just created the key, I control it
+
+        return new PwdBox(box, salt)
+    }
+    public async decrypt(pwd: string): Promise<Result<Uint8Array>> {
+        const key = await PwdBox.gen_key(pwd, this.salt)
+        return this.secret_box.decrypt(key)
+    }
+
+    private static async gen_key(pwd: string, salt: Uint8Array) : Promise<CryptoKey> {
+        const keyMaterial = await window.crypto.subtle.importKey(
+            "raw",
+            new TextEncoder().encode(pwd),
+            "PBKDF2",
+            false,
+            ["deriveBits", "deriveKey"],
+        )
+
+        return crypto.subtle.deriveKey(
+            {
+                name: "PBKDF2",
+                iterations: 250_000,
+                hash: "SHA-512",
+                salt,
+            },
+            keyMaterial,
+            {name: "AES-GCM", length: 256},
+            false,
+            ["encrypt", "decrypt"],
+        )
     }
 
     public toString() : string {
-        throw "todo"
+        const salt = misc.a2b64(this.salt)
+        const box = this.secret_box.toString()
+        return `${salt}${box}`
     }
     public static fromString<T>(data: string) : Result<PwdBox<T>> {
-        throw "todo"
+        const salt = misc.b642a(data.slice(0, 24))
+        if (salt.error()) return Result.error([])
+
+        const box = SecretBox.fromString<T>(data.slice(24))
+        if (box.error()) return Result.error([])
+
+        return Result.ok(new PwdBox(box.unwrap(), salt.unwrap()))
     }
 }