AES Text Encryptor
AES-256-GCM with PBKDF2 key derivation. Ciphertext is base64, self-contained, and decryptable only with the same passphrase.
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Worked example
The same plaintext encrypted twice produces two different ciphertexts, because a fresh salt and IV are generated each time. That is correct behaviour — identical output would leak that two messages were the same.
AES-256-GCM is authenticated encryption: it protects confidentiality and detects tampering. Alter one bit of the ciphertext and decryption fails rather than returning corrupted plaintext. The passphrase is stretched with PBKDF2-SHA256 at 210,000 iterations to make brute-force guessing expensive.
The ciphertext format
The output is base64 of salt(16) ‖ iv(12) ‖ ciphertext+tag. Everything needed to decrypt is in the blob, so you can paste it anywhere and decrypt it later as long as you still have the passphrase. There is no metadata and no server-side state.
Choosing a passphrase
PBKDF2 slows guessing but does not make a weak passphrase safe. A six-character password falls to a dictionary in seconds no matter how many iterations you run through. Use four or more random words, or a generated password you store in a manager.
What this does not protect against
It does not protect a compromised machine: anything running in the tab can read what you typed. It does not hide the fact that encryption happened. And if you lose the passphrase, there is no recovery — no key escrow exists here by design.