Why? Credit cyber-security advances. U.S. intelligence officials and other terrorism experts say that Al Qaida and related jihadist organizations have mastered cyber security in ways that many terrorism analysts find impressive, vexing and troubling.

“With these new tools, these folks are able to communicate on an almost invisible level,” said Evan Kohlmann, an NBC News terrorism analyst who tracks jihadists online. “That means not only better coordination between al-Qaida"s hierarchy and its constituents, but it also means that would-be homegrown terrorist cells can network together much more efficiently, even when they are separated by thousands of miles from each other.”

The “Mujahedeen Secrets 2” Toolkit:
Today, nearly every jihadist website has a separate section for software downloads. Some of it is basic pirated software, like versions of Microsoft Office, Adobe Photoshop and e-mail encryption files. But law enforcement officials and cyber-security experts say there’s a new item on the menu. It’s a security toolkit called “The Mujahedeen Secrets 2 Program,” an insidious free download from the Islamic Faithful Network. It features every tool needed for jihadists to hide their tracks online, including automatic message encryption and authentication, file encryption, digital signature creation and file shredding tools.

In blogs dedicated to information security, the new software has attracted a lot of attention, and concern. Jeff Bardin is a former code-breaker for the U.S. Air Force and National Security Agency. He’s also an Arabic translator, and he reviewed the “The Mujahedeen Secrets 2 Program” toolkit for the Chief Security Officer Perspectives blog.

"This provides groups like al-Qaida methods to securely transmit and wipe their files,” Bardin writes. “Not that they haven"t had such tools in the past, but a second-edition toolset demonstrates a software development lifecycle with some level of sophistication and planning. We should not underestimate our enemies."

And Bardin noted that Mujahedeen Secrets 2 is easy to find, download and use.

"I was able to create keys, encrypt and decrypt files as well as utilize all the features of the toolset. The help screens were detailed, including indexing and search capabilities. What was also of interest was the fact that the tool was in English, although the download information as well as the help files were in Arabic,” Bardin said.

How could it hinder intelligence gathering and law-enforcement efforts? “Even if these guys are ultimately arrested, there may not be a discernible forensic footprint for investigators to follow,” terror analyst Kohlmann said.

Kohlmann has watched jihadists use the web in increasingly broader ways, employing “Second Life”- which creates virtual worlds - to conduct training exercises and build social networks to proselytize and recruit. This new software, he said, is another breakthrough. 

“First, jihad supporters moved to private, password-protected message forums so that their communications never passed through any outside Internet servers,” Kohlmann noted. “The problem is, if law enforcement can identify these forums, then it can go to the hosting providers and simply demand a copy of the forum databases as they did with ‘irhaby 007,’ he said, alluding to a notorious al-Qaida cyber-jihadist arrested in Britain two years ago. The encryption features of “Mujahedeen Secrets 2” make penetration that much harder, Kohlmann added.

Roger Cressey, the former deputy director of the Counterterrorism Office at the National Security Council, agreed.

“We have known for years that the jihadis have used the Internet,” Cressey said.  “Beyond their growing sophistication in the use of commercially available tools and far more impressive tradecraft in protecting themselves on line is an ability to develop new tools specifically for their use,” added Cressey, who is also an NBC News terrorism analyst.