Combined Supporting Information File.

Text A: Detailed Description of the 3-step Strategy. Text B: Other Attacks. Text C: Properties of the Original and Improved Networks. Text D: Small Density vs Large Density. Figure A: Robustness against betweenness, closeness and HITS attack on the dolphin network and the improved network. Betweenness is the most harmful attack strategy. After only 5 attacks, the network breaks into pieces. In contrast to the betweenness attack strategy, the network can withstand 7 closeness attacks before it breaks into pieces. Closeness is a more harmful attack strategy than HITS. The reason is that HITS compiles two ranking vectors: hubs and authorities, however, on undirected networks, the hubs and authorities gain the same score, while the scores for hubs and authorities are different when the network is directed. Table A: Properties of Original and Improved Networks. (PDF)