What happens when you encrypt text with this tool
This tool uses AES-256-GCM, a modern, widely trusted encryption standard, combined with a key derived from your chosen passphrase through PBKDF2, a deliberately slow process specifically designed to make guessing your passphrase computationally expensive for an attacker, even if they somehow obtained the encrypted output.
The encrypted result is a block of Base64 text that's unreadable without the original passphrase. Both the encryption and decryption happen using your browser's built-in Web Crypto API, meaning your plaintext and passphrase are processed locally and never transmitted anywhere, not even to power the tool itself.
How to encrypt and decrypt text
To encrypt: paste your text, choose a passphrase, and click Encrypt. Copy the resulting Base64 output and store or send it. Anyone with that output still needs your exact passphrase to read it.
To decrypt: paste the encrypted Base64 text into the decryption tool, enter the same passphrase used to encrypt it, and click Decrypt. If the passphrase is even slightly wrong, decryption will fail rather than produce garbled or partial output. There's no partial credit in encryption; it either works with the exact right key or it doesn't work at all.
Why the passphrase matters more than the algorithm
AES-256 itself is extremely strong. Brute-forcing it directly isn't a realistic threat with any current or foreseeable computing power. In practice, the weak point in almost every real-world encryption failure isn't the algorithm, it's a weak passphrase that an attacker can simply guess, especially if it's a common word, a short phrase, or something guessable from public information about the person.
A strong passphrase for this kind of use is long and unpredictable, a random string of words, or a properly generated random password, works far better than a memorable phrase built around personal details. If the encrypted content genuinely matters, treat the passphrase with the same care you'd give any other password protecting something sensitive.
What this tool is (and isn't) good for
This is well suited for sharing a sensitive note, password, or piece of text with someone through a channel you don't fully trust (like a shared document or an email that might be intercepted), where you separately communicate the passphrase through a different channel. It's a reasonable way to add a layer of protection to text-based information for personal or informal use.
It's not a substitute for end-to-end encrypted messaging apps for ongoing conversations, and it doesn't provide any recovery mechanism. If the passphrase is lost, the encrypted text is permanently unreadable. There's no "forgot password" option for encryption; that's the entire point of how it works.