Sensor　network　is　an　important　approach　of　data　capturing.　User　authentication　is　a　critical　security　issue　for　sensor　networks　because　sensor　nodes　are　deployed　in　an　open　and　unattended　environment,　leaving　them　possible　hostile　attack.　Some　researchers　proposed　some　user　authentication　protocols　using　one-way　hash　function　or　using　biometric　technology.　Recently,　Yel　et　al.　and　Wenbo　et　al.　proposed　a　user　authentication　protocols　using　elliptic　curves　cryptography.　However,　there　are　some　security　weaknesses　for　these　protocols.　In　the　paper,　we　review　several　proposed　user　authentication　protocols,　with　a　detail　review　of　the　Wenbo　et　al.’s　user　authentication　protocol　and　a　cryptanalysis　of　this　protocol　that　shows　several　security　weaknesses.　Furthermore,　we　propose　a　secure　user　authentication　protocol　using　identity-based　cryptography　to　overcome　those　weaknesses.　Finally,　we　present　the　security　analysis,　a　comparison　of　security,　computation,　and　performance　for　the　proposed　protocols,　which　shows　that　this　user　authentication　protocol　is　more　secure　and　suitable　for　higher　security　WSNs.　©　2015,　Quan　et　al.;　licensee　Springer.