Paul Ryan, who received Secret Service protection last month after being picked as Mitt Romney's running mate, has his new Secret Service code name to brandish: "Bowhunter."

A campaign official told GQ's Marc Ambinder that Ryan—a skilled archer and deer hunter whose kills are well-documented—chose the code name himself. Ryan's wife, Janna, is "Buttercup."

Romney, who has had Secret Service protection since January, is known as "Javelin"—a handle that could refer to a vintage muscle car manufactured by American Motors Corp., where Romney's father, George, was once chairman.

[Related: Secret Service code names for Romney and Santorum revealed]

President Barack Obama's Secret Service code name, chosen during his 2008 presidential campaign, is "Renegade." Michelle Obama's code name is "Renaissance," while first daughters Malia and Sasha go by "Radiance" and "Rosebud," respectively.

Obama's opponent in the 2008 election, Sen. John McCain, was "Phoenix," a nod to his home state. McCain's running mate, Sarah Palin, was "Denali."

The code name tradition dates back to when communications between the Secret Service and White House Military Office were not encrypted.

"Given modern capabilities to secure communications through encryption," Ed Donovan, spokesman for the U.S. Secret Service, told GQ in March, "there is no longer any security relevance to protectee call signs."