File Encryptor

<strong>PBKDF2-SHA-256</strong> with 250,000 iterations to derive a 256-bit key from your passphrase, then <strong>AES-256-GCM</strong> with a random 12-byte nonce for authenticated encryption. Both are well-vetted modern primitives implemented in browser-native Web Crypto API. The key derivation is intentionally slow to make brute-forcing weak passphrases harder.

Magic header <code>UBX1</code> (4 bytes) + 16-byte salt + 12-byte IV + ciphertext + 16-byte authentication tag. Total overhead: 48 bytes plus the original file size. Files are tagged so any tampering or corruption is detected on decrypt — you'll get an error rather than silent garbage output.

<strong>Unrecoverable.</strong> AES-256-GCM with a strong key derivation has no shortcut — brute force is the only attack, and a 12+ character random passphrase takes longer than the age of the universe to crack with current technology. Use a password manager to store passphrases for important encrypted files. There is no recovery mechanism by design — backdoors would compromise the security guarantee.

Long is more important than complex. A passphrase of four random words from a large dictionary (e.g., 'correct horse battery staple') has more entropy than 'P@ssw0rd123!'. For sensitive files, aim for 12+ characters of mixed types or 5+ random words. Use a password manager to generate and store. Avoid quotes, song lyrics, or anything personal — those are the first things attackers try.

Yes — Web Crypto API uses the same primitives as OpenSSL, libsodium, and other audited libraries. The implementations are part of the browser, vetted by Google/Mozilla/Apple security teams. The remaining concerns are platform-level (a compromised browser, malicious extension, or compromised OS can defeat any in-browser encryption). For maximum security on critical secrets, use offline tools on a clean machine.

For incidental privacy (encrypting backups before cloud upload, sharing files outside email), yes. For HIPAA, GDPR, FedRAMP, or similar formal compliance, you may need to use specifically-certified tools and go through formal security review. The cryptography here is solid; the question is whether your compliance regime requires audited specific software.

Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.

Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.

Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.