Multilayer Security Mechanism in Computer Networks

In multilayered security infrastructure, the layers are projected in a way that vulnerability of one layer could not compromise the other layers and thus the whole system is not vulnerable. This paper evaluates security mechanism on application, transport and network layers of ISO/OSI reference model and gives examples of today's most popular security protocols applied in each of mentioned layers. A secure computer network systems is recommended that consists of combined security mechanisms on three different ISO/OSI reference model layers : application layer security based on strong user authentication, digital signature, confidentiality protection, digital certificates and hardware tokens, transport layer security based on establishment of a cryptographic tunnel between network nodes and strong node authentication procedure and network IP layer security providing bulk security mechanisms on network level between network nodes. Strong authentication procedures used for user based on digital certificates and PKI systems are especially emphasized. Keywords: Multilayered Security Systems, PKI systems, Smart Cards

Multilayer Security Mechanism in Computer Networks

In multilayered security infrastructure, the layers are projected in a way that vulnerability of one layer could not compromise the other layers and thus the whole system is not vulnerable. This paper evaluates security mechanism on application, transport and network layers of ISO/OSI reference model and gives examples of today's most popular security protocols applied in each of mentioned layers. A secure computer network systems is recommended that consists of combined security mechanisms on three different ISO/OSI reference model layers : application layer security based on strong user authentication, digital signature, confidentiality protection, digital certificates and hardware tokens, transport layer security based on establishment of a cryptographic tunnel between network nodes and strong node authentication procedure and network IP layer security providing bulk security mechanisms on network level between network nodes. Strong authentication procedures used for user based on digital certificates and PKI systems are especially emphasized.  Keywords: Multilayered Security Systems, PKI systems, Smart Cards

A configurable vector processor for accelerating speech coding algorithms

The growing demand for voice-over-packer (VoIP) services and multimedia-rich applications has made increasingly important the efficient, real-time implementation of low-bit rates speech coders on embedded VLSI platforms. Such speech coders are designed to substantially reduce the bandwidth requirements thus enabling dense multichannel gateways in small form factor. This however comes at a high computational cost which mandates the use of very high performance embedded processors. This thesis investigates the potential acceleration of two major ITU-T speech coding algorithms, namely G.729A and G.723.1, through their efficient implementation on a configurable extensible vector embedded CPU architecture. New scalar and vector ISAs were introduced which resulted in up to 80% reduction in the dynamic instruction count of both workloads. These instructions were subsequently encapsulated into a parametric, hybrid SISD (scalar processor)–SIMD (vector) processor. This work presents the research and implementation of the vector datapath of this vector coprocessor which is tightly-coupled to a Sparc-V8 compliant CPU, the optimization and simulation methodologies employed and the use of Electronic System Level (ESL) techniques to rapidly design SIMD datapaths