System Architecture Design

pSHIELDSystem Architecture DesignPU3.2.3 Cryptography TechnologiesThis section presents in a summarized way the most relevant cryptography technologies related termsand definitions used in pSHIELD project. It is divided in the following sections: attacks on cryptosystems,attacks on protocols, asymmetric and symmetric cryptography, message authentication codes and keymanagement.Elliptic curve cryptography (ECC) is becoming a powerful cryptographic scheme. Because of its efficiencyand security is a good alternative to cryptosystems, like RSA and DSA, not just in constrained devices,but also on powerful computers. ECC is very important in the field of low-resource devices such as smartcards and Radio Frequency Identification (RFID) devices because of the significant improvements interms of speed and memory compared to traditional cryptographic primitives (e.g. RSA). Memory is one ofthe most expensive resources in the design of embedded systems which encourages the use of ECC onsuch platforms. Security, implementation and performance of ECC applications on various mobile deviceshave been examined and it can be concluded that ECC is the most suitable PKC scheme for use in aconstrained environment.More and more electronic transactions for mobile devices are implemented on Internet or wirelessnetworks. In electronic transactions, remote client authentication in insecure channel is an importantissue. For example, when one client wants to login a remote server and access its services, such as onlineshopping and pay-TV, both the client and the server must authenticate the identity with each other forthe fair transaction.The remote client authentication can be implemented by the traditional public-key cryptography. Thecomputation ability and battery capacity of mobile devices are limited, so traditional PKC, in which thecomputation of modular exponentiation is needed, cannot be used in mobile devices. Elliptic curvecryptosystem (ECC), compared with other public-key cryptography, has significant advantages likesmaller key sizes, faster computations. Thus, ECC-based authentication protocols are more suitable formobile devices than other cryptosystem. However, like other public-key cryptography, ECC also needs apublic key infrastructure (PKI) to maintain the certificates for users’ public keys. When the number ofusers is increased, PKI needs a large storage space to store users’ public keys and certificates. Inaddition, users need additional computations to verify the other’s certificate in these protocols.A WSN is a wireless ad-hoc network consisting of resource-constrained sensoring devices (limited energysource, low communication bandwidth, small computational power) and one or more base stations. Thebase stations are more powerful and collect the data gathered by the sensor nodes so it can be analyzed.Routing is accomplished by the nodes themselves as any ad hoc network through hop-by-hop forwardingof data. Common WSN applications range from battlefield exploration and emergency rescue operationsto surveillance and environmental protection.Security and cryptography on WSNs meet several open problems even though several years of intenseresearch. Given the limited computational power and the resource-constrained nature of sensoringdevices, the deployment of cryptography in sensor networks is a difficult task. In D3.2 is presented theimplementations of elliptic curve cryptography in the tiny sensor nodes. Design goals for a sensor platformis to develop optimizations specifically:(i)(ii)(iii)the cost of memory addressing;the cost of memory instructions;the limited flexibility of bitwise shift instructions.D3.2 work presents efficient implementations for arithmetic of binary field algorithms such as squaring,multiplication, modular reduction and inversion at two different security levels. These implementationstake into account the characteristics of the target platform. The implementation of field multiplication andPUD2.3.2Issue 5 Page 35 of 122