In an era when corporate leaders face public skepticism and, in some cases, criminal charges, Tom Klaff says his company's software can verify when electronic documents, such as e-mails, video surveillance in digital format and audit logs, were created and by whom.

"We lock it down and prove it hasn't been altered," said Klaff, chief executive of Surety Inc. of Herndon

Klaff said the company's AbsoluteProof service will become increasingly important as electronic evidence becomes widely accepted in courts. If compliance officers, regulators, auditors or outside legal counsel challenge a company's record-keeping, Surety can prove that the records were authentic, Klaff said. AbsoluteProof can be used in court to protect intellectual property or defend patents, he said, and it's been used to time-stamp records submitted in civil and criminal court proceedings.

Here is how the software works: When an employee at a company using it sends someone an e-mail, Surety's AbsoluteProof automatically produces a digital fingerprint of the document. If questions about the e-mail come up during an audit, AbsoluteProof can call it up. If it has been changed in any way, even something as minor as inserting an extra space or period, or has been re-sent at a different time, the system will show a different fingerprint from the original one.

Two cryptographers from Bell Corp. invented the technology behind Surety and spun it into a new company 10 years ago. One of the cofounders, Stuart Haber, is still with the company as a member of its technical advisory board.

Klaff, 38, who became Surety's chief executive in March 2003, said he and his management team have spent the past year developing a business plan, building up the versatility of the product, creating government sales teams, overhauling service to make it more business-friendly and landing partners. AbsoluteProof, originally called Digital Notary Service, was relaunched late last year.

Before moving to Surety, Klaff founded Reliacast Inc., a digital media software company and become its president and chief executive. He also created and managed two ventures: College Town, a Web portal for college admissions used by students to search and apply to colleges, and a management-consulting firm to help businesses develop plans with heavy reliance on the Internet.

Surety offers customers two options: licensing the software, or subscribing to it as a Web-based service. Depending on the size of the customer, the volume of electronic records and the number of users, the annual cost for the service ranges from $50,000 to $1 million.

Although a number of products with similar technology are on the market, Klaff said that AbsoluteProof is integrated seamlessly into a company's information technology, running in the background and independent of the company's internal systems. The software does not rely on people to manage or operate it. And, he said, AbsoluteProof does not require digital signatures or sign-in keys, which can expire or be compromised.

Most important, Klaff said, is "we don't touch any of our customer's electronic records. That's unique to our service."

Surety's future relies on getting more clients, especially from research and development organizations and the government, Klaff said. The company has been in talks with Securities and Exchange Commission officials, in case electronic time-stamping is chosen as an alternative to the stock market's traditional 4 p.m. close. Klaff also said Surety plans to soon announce a partnership with Federated IT, a Washington systems integrator and reseller, to sell Surety's AbsoluteProof to the federal government.

Cynthia T. Brent, executive vice president of sales and marketing, and chief executive Tom Klaff lead Surety's efforts to help businesses and governments validate documents with an electronic time-stamp.