VPN application requirements

As people conduct more and more daily transactions online, data security issuesbecome crucial. Network frameworks implement protocols addressing a variety ofsecurity related protecting measures, such as internet protocol security (IPSec) (Kentand Atkinson 1998) and Secure socket layer (SSL) (Frier, Karlton and Kocher 1996).Both of these protocols include computation intensive cryptographic algorithms andoperations. In conventional software-only implementations, Web servers and routersare overloaded with demanding IPSec and SSL application requirements, whichresults in long response times. Nowadays, a more promising solution, networksecurity processors (NSPs), has been developed to perform various cryptographicoperations specified by network security protocols and to help to offloadcomputation intensive burdens from network processors (NPs) (Gammage 2001;Chou 2002). To achieve the outstanding performance and high throughput requiredby network protocol applications, a reasonable NSP architecture usually consists ofheterogeneous cryptographic engines, parallel DMA arrays and distributed internal