restricted information to the world, using any means necessary. On July 11, 2011, Booz Allen Hamilton, a consulting firm that does work for the Pentagon, had their servers hacked by Anonymous and leaked the same day. "The leak, dubbed 'Military Meltdown Monday,' includes 90,000 logins of military personnel—including personnel from USCENTCOM, SOCOM, the Marine corps, various Air Force facilities, Homeland Security, State Department staff, and what looks like private sector contractors." These leaked passwords wound up being hashed in SHA1, and were later decrypted and analyzed by the ADC team at Imperva, revealing that even military personnel look for shortcuts and ways around the password requirements. Alternatives to passwords for authentication The numerous ways in which permanent or semi-permanent passwords can be compromised has prompted the development of other techniques. Unfortunately, some are inadequate in practice, and in any case few have become universally available for users seeking a more secure alternative. A 2012 paper examines why passwords have proved so hard to supplant (despite numerous predictions that they would soon be a thing of the past); in examining thirty representative proposed replacements with respect to security, usability and deployability they conclude "none even retains the full set of benefits that legacy passwords already provide." Single-use passwords. Having passwords that are only valid once makes many potential attacks ineffective. Most users find single-use passwords extremely inconvenient. They have, however, been widely implemented in personal online banking, where they are known as Transaction Authentication Numbers (TANs). As most home users only perform a small number of transactions each week, the single-use issue has not led to intolerable customer dissatisfaction in this case. Time-synchronized one-time passwords are similar in some ways to single-use passwords, but the value to be entered is displayed on a small (generally pocketable) item and changes every minute or so. PassWindow one-time passwords are used as single-use passwords, but the dynamic characters to be entered are visible only when a user superimposes a unique printed visual key over a server-generated challenge image shown on the user's screen. Access controls based on public-key cryptography e.g. ssh. The necessary keys are usually too large to memorize (but see proposal Passmaze) and must be stored on a local computer, security token or portable memory device, such as a USB flash drive or even floppy disk. The private key may be stored on a cloud service provider, and activated by the use