There are many instances in business procedures where a mark of authority is required for approval or recognition. For example, the approval of a purchase order, or the 'signing off' of a completed procedure. A digital signature is the modern-day equivalent of the penned signature on paper.

The Digital Signature Field is a cost-effective means of adding digital signature capability to SharePoint lists. Users need simply to enter their password to sign items. Password entry at time of signing is the safest means of attaching a digital signature. The resulting signature is an encrypted message using a one-way security algorithm. This algorithm prevents fraudulent creation or transfer of signatures between lists, items and item versions.

The Digital Signatures Field is compatible with WSS 3.0 (SharePoint 2007) and MOSS 2007. No additional hardware is required.

• The Digital Signature Field is designed for use with SharePoint lists, but not document libraries.
  
  
• The Digital Signature Field does not fulfull the same function as SharePoint's internal content approval system. The content approval system handles management and public release of draft/final item revisions. The Digital Signature Field is a means of reliably marking an item with a user's authority.

To sign an item, simply edit the item and click 'Add Signature'.
You are asked to enter your password. This confirms you are the person signing, and not someone who may take advantage of you leaving your computer logged in while away.
At this point you can still undo the signing. However, once okayed the signature cannot be removed. This is akin to a physical signed document where the signature cannot be undone (non-repudiation).
The item is signed.

If your list is version controlled, the Digital Signature Field notifies you if the item was previously signed but has since been updated.
Opening the item, you can see when it was signed.
You may choose to re-sign the item to acknowledge the changes.

The Digital Signature Field can be added to any SharePoint list. Simply add a new column to your list of type 'Digital Signature'.