Text Encryption / Decryption

About this tool

Encrypt text with a passphrase using AES-256-GCM — a modern, authenticated encryption standard — so you can safely share sensitive notes through channels you don't fully trust, then decrypt them again with the same passphrase. Everything happens locally in your browser using the Web Crypto API; neither your text nor your passphrase is ever sent anywhere.

Each encryption uses a fresh random salt and IV, so encrypting the same text twice produces different-looking output — this is expected and doesn't affect decryption.

Frequently asked questions

What happens if I enter the wrong passphrase while decrypting?

Decryption fails outright with a clear error, rather than silently producing garbled or incorrect text — AES-GCM includes a built-in authentication check that detects the wrong key.

Is this the same as a password manager?

No — this encrypts a single piece of text for sharing or storing, on demand. It doesn't manage or remember anything for you, and closing the page discards everything.

How is the encryption key derived from my passphrase?

Using PBKDF2 with SHA-256 and 150,000 iterations, which deliberately slows down key derivation to make brute-force passphrase guessing much more expensive for an attacker.

What if the encrypted text gets modified or truncated?

Decryption will fail rather than succeed with corrupted output — the same authentication check that catches a wrong passphrase also catches tampered or damaged ciphertext.