Created
August 4, 2022 19:31
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EncryptedIdbStorage implementation using IdbKeyVal
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export class EncryptedIdbStorage implements AuthClientStorage { | |
private initializedDb: IdbKeyVal | undefined; | |
get _db(): Promise<IdbKeyVal> { | |
return new Promise(resolve => { | |
if (this.initializedDb) resolve(this.initializedDb); | |
IdbKeyVal.create().then(db => { | |
this.initializedDb = db; | |
resolve(db); | |
}); | |
}); | |
} | |
private storedKey: CryptoKey | undefined; | |
private get encryptKey() { | |
return new Promise<CryptoKey>(resolve => { | |
this._db.then(async db => { | |
if (this.storedKey) resolve(this.storedKey); | |
const key = | |
(await db.get<CryptoKey | undefined>(KEY_ENCRYPTION)) ?? | |
(await crypto.subtle.generateKey( | |
{ | |
name: 'AES-CBC', | |
length: 256, | |
}, | |
false, | |
['encrypt', 'decrypt'], | |
)); | |
this.storedKey = key; | |
await db.set(KEY_ENCRYPTION, key); | |
resolve(key); | |
}); | |
}); | |
} | |
private get iv() { | |
return new Promise<Uint8Array>(resolve => { | |
this._db.then(db => { | |
db.get<Uint8Array | undefined>(KEY_VECTOR).then(async storedIv => { | |
const iv = storedIv ?? (await crypto.getRandomValues(new Uint8Array(16))); | |
await db.set(KEY_VECTOR, iv); | |
resolve(iv); | |
}); | |
}); | |
}); | |
} | |
public async get(key: string): Promise<string | null> { | |
const db = await this._db; | |
const encryptKey = await await this.encryptKey; | |
const encrypted = await db.get<ArrayBuffer>(key); | |
if (encrypted) { | |
const decoder = new TextDecoder(); | |
const decrypted = await crypto.subtle.decrypt( | |
{ name: 'AES-CBC', iv: await this.iv }, | |
encryptKey, | |
encrypted, | |
); | |
return decoder.decode(decrypted); | |
} | |
return null; | |
} | |
public async set(key: string, value: string): Promise<void> { | |
const db = await this._db; | |
const encoder = new TextEncoder(); | |
const encryptKey = await await this.encryptKey; | |
try { | |
await db.set( | |
key, | |
await crypto.subtle.encrypt( | |
{ name: 'AES-CBC', iv: await this.iv }, | |
encryptKey, | |
encoder.encode(value).buffer, | |
), | |
); | |
} catch (error) { | |
console.error(error); | |
} | |
} | |
public async remove(key: string): Promise<void> { | |
const db = await this._db; | |
await db.remove(key); | |
} | |
} |
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I was going to add this to auth-client, but I've removed it for initial simplicity and code review