US Patent 7194618 Encryption and authentication systems and methods

In a disclosed method for authenticating a digital signature key, a record is prepared that includes an integrated combination of indicia uniquely corresponding to the key, and indicia of a covenant not to repudiate any digital signature made with the key except under specified conditions. The owner of the key performs a legally accepted execution of the record, whereby he enters into a covenant with any bearer of the record not to repudiate any digital signature made with the key except under the specified conditions.