Security measures 508 National security 350 Security, International 326 Computer security 304 Computer networks 235 Foreign relations 178 Social security 132 History 92 Prevention 89 Securities 84 Data protection 82 Derivative securities 81 Politics and government 79 International relations 75 Military policy 67 Computer crimes 58 Terrorism 57 Internal security 55 Social aspects 54 World politics 52 Government policy 48 Political aspects 45 Law and legislation 42 Management 41 International cooperation 40 Electronic data processing departments 36 Internet 36 Risk management 36 Mathematical models 34 Access control 33