This paper describes security vulnerabilities that are typical for user's authorization and authentication on the web services leading to identity theft. In an attempt to improve data confidentiality, a number of cryptographic techniques have been created. Despite all of the means to prevent oversights, it is impossible to avoid user's tendency to reuse their passwords, which lead security experts to devise a new principle where passwords are eliminated. Such systems rely on Single sign-on (SSO) protocols - one credential is enough for transparent access to the other services. SSO protocols OAuth and SAML are thoroughly analysed from security perspective and most examples given in this paper are retrieved during development. Closely associated with SSO service is federal identity and Croatian Government was'nt an exception in creating such an infrastructure - NIAS, which identifies users for the entire spectrum of web services available on e-Građani. e-Građani is missing service for safe file sharing, therefore, SafeSharing web application was developed to solve this issue. The SafeShare was developed using the SAML protocol and the OneLogin IdP. With minimal modifications, the web application would work on the national NIAS within e-Građani system.