Guttman et al. introduced a new formulation method, strand spaces theory as a new method for describing and analyzing cryptographic protocols in 1998 and Guttman introduced the ideal of information algebra and honesty to analyze the secrecy of Otway-Rees protocol in 1999. Because of the property of ideal, it can be used to show the relation between different information in some protocol. In this paper, the ideal will be appied to analyze some security properties of cryptographic protocols, such as secrecy, authentication, and so on.