Electronic Documents Time-Stamp Created

Researchers at Bellcore, the technical support organization for the seven regional Baby Bell telephone companies, said Monday that they have developed a way to time-stamp electronic documents, a potentially important breakthrough in computer security.

The service could, for example, enable banks to date computer records of transactions, potentially helping to resolve disputes with customers. Such verification could also be useful in patent cases.

The system would enable a computer user to send a mathematical fingerprint of a document--generated by a special software program--to an electronic time-stamp service. The service would stamp the fingerprint with a digital code representing the time and date and return a “receipt” to the sender. Any change in the document after it was time-stamped would cause it to generate a different fingerprint, providing an irrefutable way of proving if a computer document was altered.

Because the service would receive only a randomly generated digital fingerprint, rather than the document itself, all the information in the document would remain confidential. The Bellcore system also would provide two alternative methods of assuring that an employee of the time-stamping service couldn’t tamper with the system.

Bellcore will begin testing the system internally early next year, but it’s not clear who would actually provide the service commercially. The telephone companies would be ideal candidates, said Bellcore spokeswoman Barbara Kaufman, but it’s uncertain whether the rules that bar phone companies from offering information services would permit them to offer time-stamping.