E-government is the use of information and communication technology for public service provision in governance. Nowadays, E-government facilitates transparent, accountable, efficient and all-inclusive governing process for improved service delivery to citizens. However, the emergence of this novel innovation opened up new security vulnerabilities to citizens’ data. Comprehensive security plan for secure linkage of people, process and technology is crucial to ensure that data and network channel is protected from potential security threats. The purpose of this study is to provide a security model for protection of citizens’ data in E-government system. This paper propose information security stack, a data protection model for efficient data protection in E-government system. The information security stack comprised of citizens’ identification, authentication of identities, data confidentiality and data integrity in E-government system. First, this paper classified citizens’ identification into international, national and purposive identification. Second, acceptable form of identification for authentication of identities in E-government system depends on the security restriction imposed on the requested information. Consequently, user authentication is classified into single factor authentication, two-factor authentication and multifactor authentication depending on the use case in the E-government system. Third, data confidentiality implemented by data encryption is an information security goal for preserving the privacy of information in E-government system. The authors categorised data encryption in E-government into symmetric encryption and asymmetric encryption. Finally, ensuring the accuracy and completeness of citizens’ data is crucial for preserving data integrity in E-government system. This can be achieved by digital signature, an electronic version of handwritten signature.