Abstract: A method of dynamic password authentication used in an authentication system, in which a password generator applies a segmentation on its dynamic variable, according to predetermined segment length and positions, to produce a segment initial value and an offset for the dynamic variable. An encryption process applied on secret cryptographic key, segment initial value and offset results in the production of first dynamic cipher. Another encryption process applied on secret cryptographic key, dynamic variable etc results in the production of second dynamic cipher. Then first dynamic cipher and second dynamic cipher are combined to result in the production of a dynamic password. When a password undergoes verification executed by verifier, the verifier applies appropriate inverse processing.

Abstract: A structured digital certificate is adapted to be certified by a digital signature of a certificate authority in an unprotected form, a first protected form, and a second protected form of the digital certificate. The digital certificate includes a first type field of authorization information relevant to a first recipient and being readable in the unprotected form and the first protected form of the digital certificate, and a first cryptographic folder containing a second type field of authorization information relevant to a second recipient and being readable in the unprotected form and the second protected form of the digital certificate, but not readable in the first protected form of the digital certificate. The digital certificate is configured to permit the subject to convert the structured digital certificate from the unprotected form to at least one of the first protected form and the second protected form.

Abstract: A system and method for permitting the rental of digitized content such as music from a kiosk includes a flash memory device that is insertable into the kiosk. The kiosk derives a content key from a media key block and a media ID on the flash memory device, and then encrypts the content using the content key and records the content on the flash memory device. The flash memory device can then be removed and engaged with a player-recorder which decrypts the content and plays the content. When it is desired to check the content back in, the flash memory device is engaged with the kiosk and the content is erased. Importantly, the media ID of the flash memory device is altered during check in, such that if the user saved the content prior to check in, the content, if recorded back onto the flash memory device after check in, could not be decrypted.