NullID public guide
Offline file encryption in your browser
NullID's Encrypt / Decrypt workspace seals text snippets or files into portable NULLID:ENC:2 envelopes. The encryption and decryption operations run locally in the browser with WebCrypto.
What it does
The current envelope format uses PBKDF2 with SHA-256 or SHA-512 to derive an AES-GCM 256-bit key from your passphrase. Version 2 binds header metadata with authenticated additional data so filename and MIME fields are covered by the envelope integrity check.
How to use it
- Open Encrypt / Decrypt in NullID.
- Enter text or choose a local file.
- Choose a KDF profile or custom PBKDF2 iteration/hash settings.
- Seal the payload and download the .nullid envelope.
- To decrypt, load or paste the envelope and enter the passphrase.
Privacy and offline behavior
Payload bytes and passphrases are processed in the browser. The web application itself must first be loaded from nullid.kamranboroomand.ir; after the PWA runtime shell is cached, the root workbench can continue to load offline in supported browsers.
Limitations
- A weak or lost passphrase cannot be recovered by NullID.
- Browser memory and configured input limits constrain very large files.
- AES-GCM integrity checks fail if the envelope is corrupted or the passphrase is wrong.
- Encryption protects envelope confidentiality; it does not prove sender identity.