Patents by Inventor Theodore Stein

Theodore Stein has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Electronic funds transfer system with means for verifying a personal identification number without pre-established secret keys
    Patent number: 4797920
    Abstract: An electronic funds transfer system employs a means to verify a personal identification number PE entered by the user with the correct PIN (PT) stored at the host terminal. The remote and host terminals each generate an encryption key, and encrypt PE and PT at the respective terminals. These values are transmitted to the other terminal, where they are re-encrypted using the other encryption key. The double-encrypted numbers are then compared. The user-entered PIN can thus be verified without the need to share en encryption key between the remote and host terminals. The encryption transformation is of the type where the results of successive encryptions does not depend on the order of encryption.
    Type: Grant
    Filed: May 1, 1987
    Date of Patent: January 10, 1989
    Assignee: MasterCard International, Inc.
    Inventor: Theodore Stein