The National Security Agency has a challenge for hackers² who think they're hot stuff: prove it by working on the "hardest problems on Earth."

那些觉得自己是香饽饽的黑客们，现在美国国家安全局有一个挑战性任务给你们了。想要证明自己的实力，就来攻克这些“地球上最难的难题”吧。

Computer hacker¹ skills are in great demand in the US government to fight the cyber wars that pose a growing national security threat -- and they are in short supply.

For that very reason an alphabet（字母表） soup of federal agencies -- DOD, DHS, NASA, NSA -- are descending³ on Las Vegas this week for Defcon, an annual hacker convention where the $150 entrance fee is cash only -- no registration⁴, no credit cards, no names taken. Attendance is expected to top 10,000.

The National Security Agency is among the keen suitors. The spy agency plays both offense⁵ and defense⁶ in the cyber wars. It conducts electronic eavesdropping（偷听，窃取） on adversaries⁷ and protects US computer networks that hold super secret material -- a prize target for America's enemies.

"Today it's cyber warriors⁹ that we're looking for, not rocket scientists," said Richard "Dickie" George, technical director of the NSA's Information Assurance Directorate, the agency's cyber-defense side.

"That's the race that we're in today. And we need the best and brightest to be ready to take on this cyber warrior⁸ status," he told reporters in an interview.

The NSA is hiring about 1,500 people in the fiscal¹⁰ year which ends Sept. 30 and another 1,500 next year, most of them cyber experts. With a workforce¹¹ of just over 30,000, the Fort Meade, Maryland-based NSA dwarfs¹² other intelligence agencies, including the CIA.

It also engages in cyber-spying and other offensive operations, something it rarely, if ever, discusses publicly.

But at Defcon, the NSA and other "Feds" will be competing with corporations looking for hacking¹³ talent too.

The NSA needs cyber security experts to harden networks, defend them with updates, do "penetration¹⁴ testing" to find security holes and watch for any signs of cyber attacks.

The NSA is expanding its fold of hackers, but George said there is a shortage of those skills. "We are straining to hire the people that we need."