The number of keyloggers unleashed by hackers exploded this year, soaring by 65 percent in 2005 as e-criminals rush to steal identities and information, a security intelligence firm said Tuesday. “The overall number of keyloggers has just skyrocketed this year,” said Ken Dunham, senior engineer with Reston, Va.-based VeriSign iDefense. Keyloggers are small programs, silently installed by the attacker, typically after an earlier attack that compromised the computer through a vulnerability in the operating system or Internet browser, that record all or selected keystrokes, then sends that data to the hacker.