This master's thesis provides an unique overview of the development of security and counter-terrorism policies of the EU based on the ideas of the lesser evil, balance and tradeoffs between freedom and security, along with an analysis of the ideas themselves. Analyzing the extraordinary security policy of the EU on the one hand, and terrorism as the main security challenge of the EU on the other, this paper presents some contradictions in EU's security measures based on the idea of balancing security and freedom. Contradictions are evident, not so much in terms of constant reference to the necessity and the importance of preserving security and freedom and in the same time limiting them, how much in terms of restriction or suspension of human rights and freedoms as a way of raising the general state of security without providing specific estimates of the effectiveness of the same, with no real guarantees or evidence of achieving safety success. European integration is based on values of peace, freedom, equality and tolerance from its very beginnings. The complexity of relations between European liberal values and goals on one hand, and security necessity and justification on the other, this master's thesis is based on several examples of limiting fundamental human and civil liberties. Civil rights that are processed are based on the Maastricht Treaty, while human rights are based on the European Convention on Human Rights. When talking about the achieving, increasing or endangering the security, security is defined, according to Oxford University Dictionary, as (I) “Security as a state of feeling safe, stable and free from fear or anxiety.” and (II) “Security as procedures followed or measures taken to ensure security of a state or organization”. European security is understood as a strategy very close to the concept of European identity, that is the articulation of common European values and interests.