Add PwdWrap

src/boxes/index.ts

@@ -1,5 +1,7 @@
 export {PrivateBox} from './asymmetric'
 export {SecretBox} from './symmetric'
 export {PwdBox} from './pwd'
+
 export {PrivateWrap} from './private-wrap'
 export {SecretWrap} from './secret-wrap'
+export {PwdWrap} from './pwd-wrap'

src/boxes/pwd-wrap.ts

@@ -0,0 +1,51 @@
+import {Result} from 'result'
+import * as misc from 'misc'
+import {SecretWrap} from './secret-wrap'
+import {pbkdf} from '../pbkdf'
+
+export class PwdWrap {
+    private constructor(
+        private readonly secret_wrap: SecretWrap,
+        private readonly salt: Uint8Array,
+    ) {}
+
+    public static async wrap(pwd: string, key_to_wrap: CryptoKey) : Promise<Result<PwdWrap>> {
+        const salt = crypto.getRandomValues(new Uint8Array(18))
+        const key = await PwdWrap.get_key(pwd, salt)
+
+        const box = await SecretWrap.wrap_key(key, key_to_wrap)
+        if (box.error()) return Result.error([])
+
+        return Result.ok(new PwdWrap(box.unwrap(), salt))
+    }
+
+    public async unwrap(pwd: string) : Promise<Result<CryptoKey>> {
+        const key = await PwdWrap.get_key(pwd, this.salt)
+
+        const unwrapped_key = await this.secret_wrap.unwrap(key)
+        if (unwrapped_key.error()) return Result.error([])
+
+        return Result.ok(unwrapped_key.unwrap())
+    }
+
+    private static async get_key(pwd: string, salt: Uint8Array) : Promise<CryptoKey> {
+        return pbkdf(pwd, salt, ['wrapKey', 'unwrapKey'])
+    }
+
+    public toString() : string {
+        const salt = misc.a2b64(this.salt)
+        const box = this.secret_wrap.toString()
+        return `${salt}${box}`
+    }
+    public static fromString(data: string) : Result<PwdWrap> {
+        const salt64 = data.slice(0, 24)
+        const salt = misc.b642a(salt64)
+        if (salt.error()) return Result.error([])
+
+        const box64 = data.slice(24)
+        const box = SecretWrap.fromString(box64)
+        if (box.error()) return Result.error([])
+
+        return Result.ok(new PwdWrap(box.unwrap(), salt.unwrap()))
+    }
+}