Abstract: A method, system, and computer program product for secure distribution of content over an insecure medium, including a recipient device configured to receive content; and a sender device configured to request from the recipient device a unique identification associated with the recipient device, before sending to the recipient device, the content and a unique key associated with the content for use of the content by the recipient device. The sender device is configured to request the unique identification associated with the recipient device from the recipient device during a predetermined time interval after sending the key, and after verification of the unique identification, send a new key associated with the content to the recipient device for further use of the content by the recipient device.

Abstract: An information organizing system includes a series of paper sheets which are each foldable along several fold lines into a folded sheet of pocket-size proportions. Each portion carries imprinted information, with at least some portions also having spaces for user entry of various types of information. A pocket-size rectangular wallet has a pair of outer walls and an inner pocket for holding several folded sheets. At least one wall has edge or corner pockets on its outer side for receiving the edges of a folded sheet to hold the sheet flat against the outside of the wallet.

Abstract: A method is disclosed for eliminating group delay distortion resulting from filtering an information-carrying analog signal. The method allows an analog signal to be converted to digital form and back again with zero group delay distortion. The analog signal is first band or low pass filtered with a filter having a pass band substantially larger than that required to filter only the signal of interest. The filtered signal is then digitized at a rate appropriate to the filtered signal, digitally filtered to remove all but the signal of interest, and down sampled to the transmission rate. A substantially reversed process is described for reconverting the digital signal to analog form. The method is shown to be equally effective with a multiplexed signal.