Adobe digital signatures.

• Author: Kepczyk, Roman H.
• Position: Column

As our profession transitions to digital files, there is a growing need to be able to "digitally sign" a document and to ensure that the signature is authentic. Using a digital ID is actually more secure than a manually handwritten signature because it integrates encrypted information that is unique to the person who signed the document, which can be verified more easily than proving the identity of the person manually signing and returning a document sight unseen. Please note that using a digital ID is not the same as "pasting" a scanned image of a signature, which serves a different purpose that was covered in last month's column. A properly implemented digital ID can prove the document was not tampered with in transit and verifies the signer (or their authorized delegate) actually signed the document.

Most firms today use Adobe to create and edit PDF files, so we will describe the process in terms of that application. Adobe Acrobat and Reader can set up a digital signature that can be used to fill in a form verifying the signer's acknowledgement and putting a validating date and time stamp on a PDF document. This is done within the Edit[greater than];Preferences tab in Adobe by selecting "Security" from the left pane. Users can choose to import a scanned image of their signature or just use text or a company logo, and then select additional information they want to appear in the signature box, such as a typed name, date stamp, reason for signature, etc. Users can also set up multiple signatures for different titles or purposes that can be saved and selected as needed, including a signature that is a certified digital ID (in the advanced tab) verified by an independent third party called a Certification Authority (CA). Certificates from a CA are beneficial because they can be verified independently by anyone to whom the firm would want to send documents, so the firm should have at least one user setup.

A firm can purchase a Class 1 digital ID for email use from companies such as Verisign, Entrust, RSA and GlobalSign, which use the Public Key Infrastructure (PKI) to securely transfer files and independently verify the identity of the sender by using both a public and private key. When a user adds a digital signature to a document, Adobe generates a hash total that is...