Abstract: Methods and devices are directed to authorizing a network device to a resource over a network. An access server determines based, in part, on an attribute of the network device associated with the attribute certificate, whether the network device may be authorized access to the resource over the network. The attribute may be associated with a capability granted to the network device, a condition to be satisfied for the attribute to be valid, and the like. The attribute may belong to a group of network devices, or one or more users accessing the network through the network device. In one embodiment, the attribute certificate may be provided based on an automated security scan of the network device. In another embodiment, the access server may make the attribute available to a network resource associated with the access server.

Abstract: Apparatus, system, method and computer program product for verifying the integrity of remote network devices that request access to network services and resources. Unintended computer programs such as viruses, worms, or Trojan horses, may compromise remote devices. The invention involves downloading verification software over the web into the web browser of a client for the purpose of performing checks to verify the integrity and security of the client's device or system. The results of such checks are returned over the web to be used in security decisions involving authentication and the grant of authorization to access services and resources.

Abstract: Methods and systems are directed to authenticating a client over a network. The client generates a certificate and sends it to a server through a trusted mechanism. The server is configured to store the received certificate. When the client requests authentication over the network, it provides the certificate again, along with a parameter associated with a secure session. The server verifies the parameter associated with the secure session and determines if the certificate is substantially the same as the stored certificate. The server authenticates the client over the network, if the certificate is determined to be stored. In another embodiment, the client transmits the certificate that is generated by a third party Certificate Authority (CA) based, in part, on the client's public key.

Abstract: A speech coding system robust to frame erasure (or packet loss) is described. Illustrative embodiments are directed to a modified version of CCITT standard G.728. In the event of frame erasure, vectors of an excitation signal are synthesized based on previously stored excitation signal vectors generated during non-erased frames. This synthesis differs for voiced and non-voiced speech. During erased frames, linear prediction filter coefficients are synthesized as a weighted extrapolation of a set of linear prediction filter coefficients determined during non-erased frames. The weighting factor is a number less than 1. This weighting accomplishes a bandwidth-expansion of peaks in the frequency response of a linear predictive filter. Computational complexity during erased frames is reduced through the elimination of certain computations needed during non-erased frames only.

Abstract: A method and apparatus for improving the performance of coding systems in the presence of frame erasures or lost packets. The encoded signal is modified after transmission but prior to decoding by a decoder preprocessor. The preprocessor recognizes that a given frame has been corrupted and modifies the encoded signal so that the decoding thereof will result in improved coding system performance. Specifically, based on the decoding process and on a predetermined target signal, the encoded signal is modified so that the decoding thereof will generate an approximation to the target signal. In a first illustrative embodiment, a CELP speech coder is used and the target signal is an excitation signal comprised of all-zero excitation vectors. In this case, the portion of the corrupted excitation signal indices which identify the corresponding gain factors are set to values which represent a low gain factor.