Abstract: An efficient symmetrical-cryptographic method for using a fast but insecure host to perform encryption/decryption based on a secret key in a secure, but slow hardware token, such as a smartcard or similar device, without revealing the secret key to the host, and such that the ciphertext and plaintext are exactly the same size. The present method is suitable for use in Digital Rights Management and Software Rights Management applications which require precise interchangeability of ciphertext and plaintext in pre-allocated areas of data storage.

Abstract: An efficient symmetrical-cryptographic method for using a fast but insecure host to perform encryption/decryption based on a secret key in a secure, but slow hardware token, such as a smartcard or similar device, without revealing the secret key to the host, and such that the ciphertext and plaintext are exactly the same size. The present method is suitable for use in Digital Rights Management and Software Rights Management applications which require precise interchangeability of ciphertext and plaintext in pre-allocated areas of data storage.

Abstract: A method and system for issuing and redeeming digital coupons for requesting and granting modifications of licensed computer data products. Modifications include versions and configurations of the licensed data product as well as licensing issues related thereto. A product licensor issues authenticated coupons to customer organizations which utilize the licensed data products. The coupons are not necessarily specific to any particular computer or device, data product, version, license or configuration. Coupons can thereby be easily distributed to users within the organization. A user fills out the coupon with a request for the desired modifications and sends the coupon to the licensor, who fulfills the request by sending modification installation code directly to the user, thereby avoiding unnecessary overhead burdens on the organization. Digital coupons may be used in conjunction with external hardware devices (“dongles”) or with internal software licensing modules.

Abstract: A method for blocking Spam sent to an email address of an individual, comprising: establishing an intermediating email address, for corresponding with a party of interest without revealing the permanent email address of the individual; indicating an email message sent to the intermediating email address as Spam unless the sender thereof is the party of interest. On indicating an email message as Spam, blocking the email message. On indicating an email message as non-Spam, redirecting the email message to the permanent email address of the individual. In one embodiment of the invention, the intermediating email address expires after a predefined or arbitrary period. The method may be implemented by an email client associated with the intermediating email address, an email server, a proxy server, a gateway server and so forth.