🔐 File Encryption Tool
Password-protect any file with AES-256-GCM — the same cipher class protecting your bank connection — entirely on your device.
AES-256-GCM · PBKDF2-SHA256, 310,000 iterations · runs offline. Forgotten password = unrecoverable data, by design.
How the file encryption tool works
Your password is stretched into a 256-bit key with PBKDF2 (310,000 iterations of SHA-256, per current OWASP guidance) and a random 16-byte salt, then the file is encrypted with AES-256-GCM using a random nonce. GCM is authenticated encryption: decryption verifies integrity, so a tampered or corrupted file fails loudly instead of decrypting to garbage. Salt and nonce are stored in the output file header — they are not secrets; the password is.
The honest limits: this protects the file's contents, not its existence or size, and the protection is only as strong as the password — use a long random one from a generator. And there is no recovery: lose the password and the data is mathematically gone. That is the feature.
Frequently asked questions
How strong is the encryption?
AES-256-GCM via the browser's Web Crypto API — the same primitive used in TLS 1.3. The practical attack is never the cipher; it is a guessable password. Pair this tool with a generated 16+ character password and the encryption is not the weak point.
Can I recover the file if I forget the password?
No. There is no back door, no reset, and LazyTools never sees the file or the password. Store the password in a password manager before you delete the original.
What is the .enc file it produces?
A small header (format marker, random salt, random nonce) followed by the AES-GCM ciphertext. Decrypt it with this same tool. The salt and nonce being visible is by design — their job is uniqueness, not secrecy.
Why PBKDF2 with 310,000 iterations?
Key stretching makes each password guess expensive: an attacker must repeat all 310,000 hash rounds per attempt. The figure follows OWASP's current recommendation for PBKDF2-HMAC-SHA256.
Is the file uploaded during encryption?
No — reading, key derivation, encryption and download all happen in browser memory. Disconnect from the internet and it works identically.
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