Question 1

What can I see in a .zefer file without the passphrase?

Accepted Answer

Only the public header: format (ZEFB3 or ZEFR3), content mode (text or file), PBKDF2 iterations, compression method, and the optional public hint and note. Everything else — expiration, IP restrictions, secret question, max attempts and the content itself — is sealed inside the AES-256-GCM ciphertext.

Question 2

Is the analyzed file uploaded to a server?

Accepted Answer

No. The analyzer reads the file's bytes locally in your browser using the File API. The file never leaves your device and nothing is transmitted or stored.

.zefer file analyzer