Abstract: An electronic coupon, an electronic commerce system, and a method for the honoring of electronic coupons utilizing computing equipment are disclosed. In the method, an issuing party issues an electronic coupon to a customer. The customer presents the coupon for redemption to a redemption party. The redemption party transmits the coupon to an authentication party for authentication. If authentic, the authentication party charges the redemption party a fee and passes that fee to the issuing party. The redemption party honors the coupon for the customer and seeking reimbursement of the fee from the issuing party. The electronic coupon has a plurality of data fields, including: a coupon identifier, x, a first one-way hash function field, f(x), and a secure signature field.

Abstract: A method for data embedding in a digital image under the constraint of a pre-specified upper bound value on the amount of change in the value of a property associated with the image. For compression tolerant data hiding in digital images, a property is selected in which the required information can be embedded. The property should be such that the value obtained from the property before and after a lossy compression does not change by a significant amount, and the change should be bounded. The property should be such that a property value as obtained from the image will not vary due to compression, but only due to malicious tampering. The value obtained from the property is stored so that the image can be verified. The complete image is considered in deciding whether to increase or decrease the property value in a particular region.

Abstract: A system for implementing a virtual class and distance education via a computer network is disclosed. The process carried out by the system involves receiving signals from one or more instructor entities, the signals including lesson material designated as belonging to one or more interest groups. The lesson material is sent in advance to student entities listed in one or more of the interest groups to which the lesson material is designated as belonging. Signals from one or more student entities are received requesting admission to a particular class and instructions are sent to student entities to control the display and execution of the lesson material. Interaction amongst student entities, or between student entities and instructor entities, are facilitated and moderated.

Abstract: A verification system for still images that embeds a watermark so that no visual artifacts are created in the images and thus maintains the visual quality of the image. The algorithm embeds information in an uncompressed image so as to later detect the alteration of the image, as well as the location of the alteration. The embedding of information into a source image is based on a defined mapping process. An image plane consists of macroblocks, which are themselves comprised of microblocks. A code is embedded corresponding to the value of this image property in each macroblock. The specific sequence of microblocks used for embedding this information in the watermarking image plane is a unique function of this property for the corresponding set of microblocks in the indexing image plane. This information can be later decoded from the stamped image. The watermark is embedded by combining the pixel values of the image with the watermark. The watermark is altered if the image is altered.