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.