Contactees tell us that "aliens" communicate by somehow beaming words and images into their heads and the words are in the language of the receiver. But of course, researchers totally discount the experience of these people and instead, decide to promulgate their own ideas. At the moment, a group of them are studying how to decipher coded messages that extraterrestrials may send us in the future.
Prominent NSA cryptologist Lambros D. Callimahos was the leader in this venture. On the Open Minds website, Alejandro Rojas says he "played a crucial role in shaping cryptologic development at NSA." Thinking that aliens might visit us soon, he "developed a special class, designated CA-400, for elite cryptanalysts, if they passed they would become members of what was labeled the Dundee Society. The group's real purpose was so secret that it was named after an empty Dundee marmalade jar he kept his pens in on his desk." This eventually turned into the SETI program. Callimahos based his ideas on the work of Frank Drake, who thought the possibility of life in space was very large.
Rojas quotes Callimahos as saying, "Unless we're terribly conceited (a very unscientific demeanor), we must assume that the 'others' are far more advanced than we are." However, he didn't feel that aliens might be dangerous, the way Stephen Hawking apparently does. One thing we can give Callimahos credit for: He wrote a secret NSA paper which states that the UFO phenomenon and possible extraterrestrial interaction should be taken much more seriously and says there are credible witnesses whose experiences cannot be written off.