“…Moreover, the key secret that maintains sensitive data secret. As it is clear from Table 2, the schemes [91], [93], [94], [101]- [105], [115], [118], [120], and [125] are the most effective protocols ensuring all security features, then the protocols [95], [97], [98], [106], [107], [111], [113], [116], [117], [119], [122], and [123] which do not ensure the key secret, and [108], [109] that do not ensure the perfect forward secrecy. However, scheme [112] secures mutual authentication, anonymity, intractability, and key agreement, and scheme [121] secures mutual authentication, anonymity, key agreement, and perfect forward secrecy.…”