How do I encrypt text with a password?
Enter your text and a password, and this tool encrypts it with AES-256-GCM. Your password is stretched into a key using PBKDF2 (SHA-256, 250,000 rounds) with a random salt, so the same password never produces the same output twice. Everything runs in your browser and nothing is uploaded.
Password-encrypt text, without trusting a server
This tool turns readable text into an unreadable block that only your password can unlock, and back again. You paste in a message, type a password, and press Encrypt: the output is a base64 string you can email, message or store anywhere, safe in the knowledge that without the password it is just noise. To read it back, whoever has the password pastes the block in, switches to Decrypt and gets the original text.
Every step happens inside your browser through the built-in WebCrypto API. Your text and your password are never uploaded, logged or seen by anyone, which is the whole point: you are not trusting this website with your secret, only with the maths.
How your password becomes a key
A password is not used directly as an encryption key, because people pick short, guessable passwords and real keys need to be long and random. Instead the password is run through PBKDF2, a deliberately slow function that mixes it with a random salt and repeats 250,000 times to produce a full 256-bit key. The slowness is the feature: it means an attacker who wants to guess passwords has to do that heavy work for every single guess.
Because the salt and IV are random and new each time, encrypting the same text with the same password twice gives two completely different outputs. That is correct and intended: it stops anyone spotting that two messages are identical. Both values are tucked into the output, so decryption can read them back and still reproduce the key.
Why AES-256-GCM
AES is the Advanced Encryption Standard, chosen by the US government in 2001 and used everywhere from your bank's website to your phone's storage. The 256 refers to the key length. GCM, or Galois/Counter Mode, adds authentication on top of encryption: it does not just scramble the text, it also produces a tag that proves the text has not been altered. If a single character of the encrypted block is changed or corrupted, decryption fails outright rather than quietly returning wrong text. That is why a wrong password and a tampered message both simply refuse to decrypt.
When to use it, and when not to
It is a good fit for encrypting a note before saving it in a cloud drive, protecting a block of text in an email, or handing someone a secret when you can share the password separately through a different channel. Share the password by voice or a different app, never in the same message as the ciphertext.
It is not a replacement for a proper end-to-end encrypted messenger for ongoing conversations, and it cannot protect you if your device itself is compromised. The strength of everything here rests on one thing you control: the password. A short or reused password can be guessed no matter how strong the cipher is, so use a long, unique passphrase, and remember that if you lose it the text is gone for good, because there is deliberately no way to recover it.
How we work it out
AES-256-GCM with a 256-bit key derived from your password by PBKDF2-SHA-256 (250,000 iterations) and a fresh 16-byte random salt, plus a 12-byte random IV per message. The output is base64 of salt + IV + ciphertext; decryption reverses this and fails cleanly if the password is wrong.
Frequently asked questions
Is my text or password sent anywhere?
No. All encryption and decryption happens in your browser using the built-in WebCrypto API. Your text, your password and the result never leave your device, so the tool is safe to use with private notes and messages.
What happens if I forget the password?
The text is unrecoverable. There is no back door and no reset: AES-256 with a proper key-stretching step is designed so that guessing the password is infeasible. Store the password somewhere safe, because losing it means losing the text for good.
Why does encrypting the same text twice give different output?
Because a fresh random salt and IV are generated each time. This is deliberate and correct: it means an observer cannot tell that two outputs came from the same input, and it is why AES-GCM is secure. Both values are stored inside the output so decryption still works.
How strong is the encryption?
The cipher is AES-256-GCM, the same standard used by banks and governments, and the key comes from your password via 250,000 rounds of PBKDF2-SHA-256 to slow down guessing. The real weak point is the password itself, so use a long, unique passphrase.
Can I use this to send a secret to someone?
Yes, if you share the password with them through a separate, trusted channel (not the same message). They paste the output here, switch to Decrypt, enter the password and read it. For ongoing secure messaging, a dedicated end-to-end encrypted app is a better fit.