What "encrypting" a PDF actually changes
PDF encryption scrambles the document's content so it can't be opened without the correct password, using the same AES/RC4-based standard supported by Adobe Acrobat and virtually every other PDF reader — an encrypted PDF from PrivaPDF opens normally in any compliant viewer once the password is entered.
Because the encryption key is derived from your password inside the browser's WebAssembly runtime and never transmitted, PrivaPDF itself has no way to open a file you've encrypted — if you lose the password, the document is genuinely unrecoverable, the same as with any other properly encrypted PDF.