Abstract: A method for protecting digital content from copying and/or other misuse as it is transferred between one or more computationally constrained devices over insecure links, includes preliminarily authenticating that both a content source and a content sink are compliant devices, and transferring content between compliant devices. In a further aspect of the invention, in the background, concurrently with the transfer of content, at least a second cryptographic process is performed. In an embodiment, establishing a preliminary control channel includes exchanging random challenges between devices, encrypting, under a shared secret key, and hashing the exchanged random challenges, exchanging the results of the encryption and hash functions and then verifying that the appropriate results have been generated.

Abstract: An integrated circuit includes: a digital signature module coupled in the integrated circuit so as to receive a time of day signal string from a clock module and digitally sign the signal string.

Abstract: In accordance with one embodiment of the invention, an integrated circuit includes: a digital signature module coupled in the integrated circuit so as to receive a time of day signal string from a clock module and digitally sign the signal string.

Abstract: A method for protecting digital content from copying and/or other misuse as it is transferred between one or more computationally constrained devices over insecure links, includes preliminarily authenticating that both a content source and a content sink are compliant devices, and transferring content between compliant devices. In a further aspect of the invention, in the background, concurrently with the transfer of content, at least a second cryptographic process is performed.

Abstract: A method for protecting digital content from copying and/or other misuse as it is transferred between devices over insecure links, includes authenticating that both a content source and a content sink are compliant devices, establishing a secure control channel between the content source and the content sink, establishing a secure content channel, providing content keys, and transferring content.In a further aspect of the present invention, at least one certificate revocation list version identifier is exchanged between the content source and the content sink, and if the received certificate revocation list version identifier is more recent than the certificate revocation list version identifier stored in the receiving device, then the certificate revocation list of the receiving device is updated.

Abstract: A method and apparatus in accordance with the present invention, in response to a request for access to a secure resource, modulates an illumination light source, such as a computer display, in a pseudo-random sequence to produce time-varying light emissions that reflect off of the object being imaged by an image recognition system. The authentication system controls both the generation of the modulated light emissions and the detection of their reflection from the object, in real time. This prevents an adversary from spoofing a visual authentication system by replaying recorded images. In further aspects of the present invention, combinations of visible and infrared illuminations may be used.

Abstract: A cryptographic system and method for secure distribution and management of cryptographic keys for use in a DVD copy protection scheme is disclosed. A DVD disc having compressed, encrypted content written on a first portion of the disc, and the content encryption key, itself encrypted with a second key and written out of band on a second portion of the disc is used to provide content, key, and control information to a DVD drive according to the present invention. The DVD drive is coupled to a decompressor and a video controller. The video controller and DVD drive engage in a handshaking protocol in which all of the communication between them is encrypted. After verifying that the video controller is registered and not known to be compromised, the DVD drive passes the content key and control information to the video controller, and the compressed, encrypted content to the decompressor.