To enter the “How Can I Work for N.S.A.?” section of the site, children click on a picture of a bucktoothed rabbit, who says in his biography that he likes listening to hip-hop and rock. In his free time, the bunny says, he participates in cryptography competitions with other cartoon characters named Decipher Dog and CryptoCat.

“As a signals analyst, you will work with cutting edge technology to recover, understand and derive intelligence from a variety of foreign signals found around the world,” children are told in the future employment section. “You will also attempt to identify the purpose, content, and user of these signals to provide critical intelligence to our nation’s leaders.”

Civil libertarians, not surprisingly, said the website was propaganda. Experts on early childhood education and marketing to children said the tactics used by the N.S.A. were similar to the way McDonald’s puts toys in its Happy Meals.

“This is the N.S.A. putting on its best face and the way it wants to present itself without anyone else providing their opinions or making noise — and for children, it may make them feel good about what the N.S.A. does,” said Nina Huntemann, a professor at Suffolk University who studies the social impact of new media.