Text Encrypt Decrypt Tool

AES is fine for almost everything — RC4 is there but you shouldn't need it

Pick AES, type a passphrase, paste your text, and encrypt. That's the normal flow. The output is a Base64 string you can safely put in an email, a config file, or a database column. The passphrase drives the key derivation — it's not used directly as the key, it's run through a key derivation function first, which means a short human-readable passphrase still produces a properly sized cryptographic key. To decrypt you need the exact same passphrase and algorithm. If you change either, you get garbage back or an error. RC4 is included for compatibility with older systems, but it has known weaknesses and you shouldn't use it for anything new. TripleDES is the middle ground — stronger than RC4, weaker than AES, occasionally required when working with legacy APIs that predate AES support.

Nothing leaves your browser — check the network tab if you want to be sure

All the cryptography here runs in JavaScript in your browser tab, using the CryptoJS library. Your text and your passphrase are never sent to any server. If you have any reason to be cautious about this, open your browser's developer tools, go to the Network tab, and run an encryption while watching for outbound requests. You'll see nothing. That matters especially for this kind of tool — the whole point of encrypting something is that only you and whoever has the passphrase can read it, so the tool itself shouldn't be a weak point. The one situation where this caveat applies: if your machine is compromised, browser-side crypto doesn't protect you there. For anything genuinely sensitive, a local command-line tool or hardware-backed key store is the appropriate level.