Signing PDF files enables the receipient to verfiy, that the document is from the relevant person and has not been modified after signing. This is done with a private/public key mechanism. The private key is used to encrypt a fingerprint of the document (the hash). This can be decrypted with the public key and then be compared with a hash created from the present document. These only match, when private and public key match and the document has not been modified.
Certificate file: A digital Certificate in a PFX12 file that is enable to create digital signatures. It stores the private key which is used to encrypt the hash value. You can either type in the path or use the “…” button to search through your system.
You can get free certificates at http://www.cacert.org. Please keep in mind that this is not a register-and-go service. CAcert is based on a web of trust, where you are verified by people and can verify other people. It takes a bit of work to get enough points for a trusted status, but it really is free and you should give it a try.
Set password: You can save the password, to skip the request during the print job. The opened Dialog automatically checks if the password is valid for the certificate. To delete the saved password, just press Remove in the Set password Dialog. Afterwards you must leave the Profile Settings with Save.
For automatic saving, you must set all required passwords.
Reason: The reason for the cerfitifacte. This is a piece of text that describes why the document is signed.
Contact: The name of the contact person that signed the file.
Location: Place (Country, City etc.) where the file has been signed.
Display Signature in document: Creates an icon in the PDF file showing the validity of the signature. Select on which page the signature icon will appear. Choose between first and last page or set a custom page. If the custom page is bigger than the number of pages, the signature will appear on the last page. Among the page you can set the coordinates for the icon. The icon is a rectangle defined by the LeftX/Y and RightX/Y values. The size of the icon results from the coordinates.