Abstract: The specification relates to the encryption of data transmitted over a broadband multiple access bi-directional hybrid fiber/coax (HFC) network. The method supports downstream broadcast encryption from headend to cable modem, and also provides for encryption of transmissions from cable modems back to the headend. Although the present invention is described in relation to an HFC network, it is also equally applicable to a cellular wireless communications environment or any other digital broadcast medium. The invention is implemented in two subdivisions, a slow but secure software encrypting algorithm, and a fast but less secure hardware encrypting algorithm. The combination produces the security of the software subdivision, with the encrypting speed of the hardware subdivision. The encryption method and apparatus supports the various access and transmission modes, such as STM, ATM, and VL.

Abstract: A security node disposed in the telecommunications network connecting calling and called parties transforms information (which can be voice, data, facsimile, video and other types of calls or messages) encrypted in a first format to (a) encrypted information in a different format or to (b) non-encrypted information, and vice-versa. The node is accessible from any location connected to the network. By routing calls or messages originated by the calling party and destined for the called party via the security node, and providing appropriate control signals to the node, the information may be encrypted only over a portion of the transmission path between the parties, and clear over the remainder of the transmission path. Alternatively, the information may be encrypted in different portions of the path using different encryption algorithms.

Abstract: A secure embedded memory management unit for a microprocessor is used for encrypted instruction and data transfer from an external memory. Physical security is obtained by embedding the direct memory access controller on the same chip with a microprocessor core, an internal memory, and an encryption/decryption logic. Data transfer to and from an external memory takes place between the external memory and the memory controller of the memory management unit. All firmware to and from the external memory is handled on a page-by-page basis. Since all of the processing takes place on buses internal to the chip, detection of clear unencrypted instructions and data is prevented.

Abstract: A security node disposed in the telecommunications network connecting calling and called parties transforms information (which can be voice, data, facsimile, video and other types of calls or messages) encrypted in a first format to (a) encrypted information in a different format or to (b) non-encrypted information, and vice-versa. The node is accessible from any location connected to the network. By routing calls or messages originated by the calling party and destined for the called party via the security node, and providing appropriate control signals to the node, the information may be encrypted only over a portion of the transmission path between the parties, and clear over the remainder of the transmission path. Alternatively, the information may be encrypted in different portions of the path using different encryption algorithms.