![]() |
![]() |
![]() |
Help: Signing DocumentsThere are a few ways to sign a PDF document.
Adding a Basic SignatureInsert a scanned image of your signature into a PDF just as you would any other image. When you do, it's often necessary to make the background of the signature transparent.
Tips for Adding A Signature
Using an interactive signature field![]() PDFpen supports using the signature fields which come in certain forms. An interactive signature field aids in signing a form by providing a larger space to sign, and multiple ways to sign.
Digital SignaturesThe goal of a digital signature is to provide a way for the document's recipient to verify the identity of the one who signed it, and that nothing has changed since it was signed. To accomplish this, digitally signing a document means applying a digital certificate to the document. This certificate is the way to ensure the integrity and authenticity of the document once signed.
Digital CertificatesWhen you open a document which was digitally signed, PDFpen will validate the digital certificate it was signed with and inform you whether the certificate is from a trusted source. In order for you to digitally sign a document you need to obtain a digital certificate from a certificate provider, such as those on the Adobe Approved Trust List (AATL). This may involve purchasing a certificate, and may involve installing software from the provider. What is a Digital Certificate?A digital certificate is a piece of data, typically stored in files or on an external device, such as a secure USB dongle, which contains:
Along with your digital certificate you create a private key. Unlike the public key which helps make up the certificate, the private key is typically stored on your system keychain where other secure items, like passwords, are stored. Documents are signed using this private key. Your digital certificate, containing your public key, along with your identity information and the digital signature, is embedded in any documents you sign. It's safe to give your public key to others. You must keep your private key secure. SecurityDigital certificates have a "chain of trust", which begins with a root certificate, may include intermediary certificates, and ends with the certificate of a person or company. Adobe's applications only trust signatures with root certificates from the Adobe Approved Trust List (AATL). Just because a certificate is verified as trusted does not mean it always must be so. For example, if you lose your laptop or your secure USB dongle someone else could gain access to your private key, which means the integrity of the certificate has been compromised. In an event such as this it's possible to revoke the digital certificate. Issuers of digital certificates maintain systems to check whether a digital certificate has been revoked or remains valid. One system is called the Online Certificate Status Protocol (OSCP), and the other is Certificate Revocation Lists (CRLs). PDFpen is capable of checking both, as necessary. ValidationWhen you open a PDF with a digital signature using PDFpen, the following steps occur to validate the signature:
States of ValidationWhen you view a signed document in PDFpen the document will display one of three states.
Hover your cursor over the validation icon badge for information about the validation. Click on it to see the certificate details. Signing a PDF with a Digital Signature
Please note that only digital certificates from Adobe Approved Trust List (AATL) issuers are trusted by the Adobe applications. Smile's testing, as of February 2016, suggests that only DigiCert and GlobalSign offer digital certificates compatible with use on macOS. Each requires special driver software from the certificate issuer. Self-Signed CertificatesIt's possible to create your own digital certificate, rather than obtaining one from an issuer. This is called a self-signed certificate. Self-signed certificates do not have a chain of trust and cannot be revoked. Therefore, they are not suitable for establishing the authenticity of a document. They're only suitable for verifying document integrity. Create a Self-Signed Certificate
|
||
© 2003-2017 SmileOnMyMac, LLC dba Smile. All rights reserved. PDFpen and PDFpenPro are registered trademarks of Smile. The Smile logo is a trademark of Smile. |