*3.1.3. Symmetric x asymmetric cryptography*

The IEEE 802.15.4 standard of 2011 defines parameters for low-range personal area networks (LR-WPANs). The first version of this standard was launched in 2003, and the second one [20] was appointed to be the standard communication protocol for WSNs. The encryption mechanism specified in IEEE 802.15.4 standard is based on encryption symmetric key. But according to Sen [23] recent studies have shown that it is possible to implement public key encryption using the right selection of algorithms and associated parameters, and optimization techniques for low power. In some cases the public-key cryptography efficiently obtained similar or even greater than symmetric key encryption using keys smaller. According to Struik [24] is already proven that public-key algorithms developed are suitable for hardware in WSNs.
