Wherever we turn we cleary see connections between computer systems. Systems are connected in all sorts of ways, and all of those ways are created to fulfill some user request. One great example of such connection between multiple systems is the Internet. Internet in it’s core is connection between systems and connection between different systems between different users. User autentificates and introduces himself to some service by using his username and password, or some other form of identification. Since there are a number of services and users memory is limited and not perfect, users tend to reuse their usernames, and sometimes even passwords across multiple different services. That kind of approach to user security creates a big security problem: problem where compromitation of username and/or password on one service can enable an evil attacker to authentificate with the users identity over the whole range of services that are frequently used by the user, e.g. Facebook, Google, Twitter... Because of that reason security experts devised a principle of authentification of users over the whole range of platforms using a single username and password, moreover a unique system which allows access to all those other services. The most famous implementation of such a system in the Republic of Croatia is NIAS (National identifi- cation and authentification system), specifically a system called e-Gradani ¯ which is the main system for user access to a range of services. That system is used so that citizens could have easier and more secure access to services such as e-Policija and e-Porezna, etc. With such an implementation it’s more secure and easier to manage electronic identites of citizens and their authentification so that they could communicate with the State on matters of vehicle registration, health insurance, etc. 20 One secure system which guards electronic identitetes allows us to close the problem of compromised identitet by a computer attack over an insufficientlly protected service on which we were using the same username and password as somewhere else, but we opened a possibility of attack on this new secure system which manages all the identitetes. In case this system is successfully attacked all of the services which rely on this system to authentificate users are compromised. As such this approch has merrits and faults, but still it’s quite useful at this moment in time, it’s being used by all the major IT companies such as Google and Facebook, and will surely stick around for quite some time, at least till we figure out a new way to protect our electronic identitets.