Unlocking a PDF removes the protection password from a document you already know the password for. This function is useful when you want to share a document without requiring others to enter a password, or when you want to edit a protected PDF that you own.
OnlinePdfEditor is not a tool for breaking protection on other people's documents: it always requires you to provide the correct password to proceed. Without a valid password, decryption is mathematically impossible with AES-256. The tool is designed exclusively for legitimate situations: you protected a PDF for secure sending and now want to remove the protection for internal use, or you received a protected PDF with a password communicated separately and want a more convenient file to work with.
The technical distinction from 'Protect PDF' is clear: protecting applies AES-256 encryption to the document; unlocking performs decryption using the key derived from your password and saves the resulting document without any restrictions. The unlocked PDF is identical to the original in content and quality — no degradation, recompression, or metadata loss occurs.