Question 1

How does this encryption work?

Accepted Answer

Your passphrase is run through PBKDF2 (SHA-256, 250,000 iterations) with a random salt to derive a 256-bit key, which is used to encrypt your text with AES-256-GCM and a random IV. The salt, IV, and ciphertext are packed together and base64-encoded into one string you can copy and share.

Question 2

Why does encrypting the same text twice give different results?

Accepted Answer

Each encryption generates a new random salt and IV, so the output is different every time even with identical text and passphrase. This is expected and does not affect decryption — the salt and IV needed to reverse it are stored inside the ciphertext itself.

Question 3

What happens if I use the wrong passphrase to decrypt?

Accepted Answer

You'll get an "Incorrect passphrase or corrupted ciphertext" error. AES-GCM includes a built-in authentication check, so a wrong passphrase is rejected outright rather than producing garbled text.

Question 4

Is my text or passphrase sent to a server?

Accepted Answer

No. Encryption and decryption run entirely in your browser using the native Web Crypto API. Your text and passphrase never leave your device — there is no upload, no network request, and nothing is stored.

Question 5

How strong should my passphrase be?

Accepted Answer

The encryption is only as strong as your passphrase. Use a long, unique passphrase (a random passphrase of several words is a good approach) — short or common passphrases can still be guessed even with strong AES-256 encryption behind them.

Question 6

Can I decrypt this ciphertext somewhere else, like in my own code?

Accepted Answer

Yes, as long as you replicate the format: base64-decode to get [1-byte version | 16-byte salt | 12-byte IV | AES-256-GCM ciphertext+tag], derive the key with PBKDF2-SHA256 at 250,000 iterations, and decrypt with AES-GCM.

Text Encryptor & Decryptor (AES)

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Frequently Asked Questions

How does this encryption work?

Why does encrypting the same text twice give different results?

What happens if I use the wrong passphrase to decrypt?

Is my text or passphrase sent to a server?

How strong should my passphrase be?

Can I decrypt this ciphertext somewhere else, like in my own code?

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