Encrypt and decrypt text with a passphrase using the Web Crypto API. The output is a portable base64 blob you can paste anywhere. Everything happens locally in your browser and nothing is sent to any server.
All cryptography runs locally with the browser Web Crypto API. No external dependencies, works offline.
Ciphertext (base64)
How the scheme works
Each encryption uses authenticated symmetric encryption with a key derived from your passphrase:
Cipher: AES-256-GCM (authenticated, so tampering and wrong keys are detected).
Key derivation: PBKDF2 with SHA-256 and 250000 iterations.
Random salt: 16 fresh random bytes per encryption, used for key derivation.
Random IV: 12 fresh random bytes per encryption, used by GCM.
Output layout: salt, then IV, then ciphertext, concatenated and encoded as base64. Everything needed to decrypt (except the passphrase) travels with the blob.
Warning: a forgotten passphrase means the data is unrecoverable. There is no reset, no backdoor, and no recovery. Keep your passphrase safe.