A Digital Postmark

A Digital Postmark (DPM) is a technology that applies a Trusted Time Stamps issued by a Postal Authority to an electronic document, validates electronic signatures, and stores and archives all non-repudiation data needed to support a potential court challenge.

'Trusted Timestamping'

The process of securely keeping track of the creation and modification time of a document. Security here means that no one—not even the owner of the document—should be able to change it once it has been recorded provided that the timestamper's integrity is never compromised.

The administrative aspect involves setting up a publicly available, trusted timestamp management infrastructure to collect process and renew timestamps.

The Process

• An electronic document is created
• Digital Postmarking client software signs the document locally
• The signed document is sent to the Digital Postmarking service for postmarking
• Upon receipt, the Digital Postmark service first validates the authenticity of the signature
• If the signature is valid then a timestamp is generated by the DPM service as a counter-signature that includes the date and time
• The document, signature, validation results and timestamp are stored in the Digital Postmark non-repudiation database
• A Digital Postmark Receipt, including the validation results and the timestamp, is returned to the client software
• The client software wraps the original document with the DPM receipt
• To verify the signature, local cryptographic (as shown in a picture below) verification can do a quick check of integrity or the full receipt or even the original document can be retrieved from the DPM service using the XML Verify request by other parties at a later date and compared with the receipt stored with the document.

Benefits of Digital Postmarks

The DPM is fundamentally a non-repudiation service supporting designed to protect the sanctity of mail in its digital form:

• Digital signature verification (as diagram shown)
• Timestamping of successfully verified signatures
• Standalone timestamping
• Encryption
• Validation of certificate trust chains
• Storage and archival of all non-repudiation evidence data required to support subsequent challenges

Working with current infrastructure, it is easy to implement - providing functionality even with no client-side software, and provides automated functionality with client software.

Additional Benefits

• Proactive differentiation "good" email from spam and phishing.
• Improved service quality by applying the same s tandards that govern physical mail to email.
• Guaranteed delivery of legitimate emails unlike other timestamping standards (sender id and DKIM).
• Compliance with all federal laws and regulations.
• Postal authority enforcement: Mail fraud is virtually non-existent with physical mail due to the legal framework and the vigorous efforts of the U.S. Postal Inspection Service. Digital Postmarks have the same legal recourse for email fraud as for physical mail fraud.
• Significant mailing cost reduction to only a few cents

Applicable Services

The Digital Postmark can be used for a variety of business applications:

• signing Web forms and documents
• delivery of secure documents
• interpersonal messaging

Prepared by : Nik Noor Diana Mohd Noor (2007239692)