Is my text or passphrase uploaded when using this AES encryption tool?

No. Encryption and decryption run in your browser using the Web Crypto API. No request carrying the text or passphrase is made.

Can the text be recovered if I forget the passphrase?

No. There is no key escrow, reset or back door. A forgotten passphrase means the ciphertext cannot be decrypted by anyone.

Can I decrypt the result with other software?

Yes. The output is Base64 of a version byte, a 16-byte PBKDF2 salt, a 12-byte AES-GCM IV and the ciphertext, using PBKDF2-SHA256 at 250,000 iterations and AES-256-GCM.

AES-256-GCM has no practical break. The realistic weak point is a short or reused passphrase, so use a long one.

AES Encryption Online

Encrypt text with a passphrase using AES-256-GCM, and decrypt it back again. The work is done by your browser's own cryptography engine - your text and your passphrase never leave the page.

Text to encrypt

Passphrase

There is no recovery. If you forget this passphrase the text cannot be decrypted by anyone, including us.

What this tool actually does

Your passphrase is not the encryption key. It is stretched into one using PBKDF2-SHA256 with 250,000 iterations and a fresh random 16-byte salt, which makes guessing attacks far slower than testing the passphrase directly.

That derived key encrypts your text with AES-256-GCM under a fresh random 12-byte IV. GCM is an authenticated mode, which is why a wrong passphrase gives you a clean "could not decrypt" instead of silent garbage - and why tampering with the ciphertext is detected rather than ignored.

The result you copy is Base64 of version byte + salt + IV + ciphertext, so a single string carries everything needed to decrypt it later. Everything runs through the browser's built-in Web Crypto API - there is no request carrying your text or passphrase, on this page or anywhere else.

One honest difference from the Snoq app

This page derives keys with PBKDF2, because that is what browsers implement natively. The Snoq desktop app uses Argon2id, which is memory-hard and meaningfully more resistant to GPU and ASIC cracking than PBKDF2 at any iteration count. For pasting a short secret into an email, PBKDF2 with a strong passphrase is fine. For a notes database you keep for years, Argon2id is the right tool - and that is the one running in the app.

Questions

Is my text or passphrase uploaded?

No. Encryption and decryption both run in your browser. There is no endpoint on this site that accepts the text or the passphrase. Open the Network tab in developer tools and encrypt something - you will see no request.

Can you recover my text if I forget the passphrase?

No, and neither can anyone else. There is no key escrow, no reset and no back door. That is the point of the design, but it does mean a forgotten passphrase is final.

Can I decrypt this somewhere else?

Yes, if you reproduce the scheme: Base64 decode, read the version byte, take the next 16 bytes as the PBKDF2 salt and the following 12 as the AES-GCM IV, derive with PBKDF2-SHA256 at 250,000 iterations, then decrypt the remainder with AES-256-GCM. It is deliberately a standard construction, not a custom one.

Is AES-256 actually secure?

The cipher is not the weak point - your passphrase is. AES-256-GCM has no practical break. A short or reused passphrase, however, can be guessed no matter how strong the cipher is, so use a long one.

Encrypting one note at a time gets old

Snoq keeps a whole notes database encrypted with AES-256 and Argon2id on your own disk - unlocked once, then just works. Rich text, tabs, full-text search, PDF export. Free, Windows, no account and no cloud.

Download Snoq for Windows