Introduction.- Law 1, Attackers Will Always Find Their Way.- Law 2, Know the Assets to Protect.- Law 3, No Security Through Obscurity.- Law 4, Trust No One.- Law 5, Si Vis Pacem, Para Bellum.- Law 6, You Are the Weakest Link.- Law 7, Security Is No Stronger Than Its Weakest Link.- Law 8, If You Watch the Internet, the Internet Is Watching You.- Law 9, Quis Custodiet Ipsos Custodes? Law 10, Security Is Not a Product, Security Is a Process.- Conclusions.- Abbreviations.- Acronyms.- References.- App. A, A Short Introduction to Cryptography.