While Def Con packs more events, workshops, and contests than the storage space of a ZIP drive, one of the longest lasting traditions revolves around the mysteries of the conference badge, itself.

This year, Def Con celebrates its 21st birthday with a card-themed cryptographic challenge based on the standard playing card deck -- except this is no ordinary card deck.

Attendees of Def Con 21 are all given custom badges, which are actually elegantly fabricated PCB boards complete with delicately carved copper contact points, mathematical constants, binary numbers, Chinese characters, and more.

In an improved and renewed focus on social engineering, Ryan "LostboY/lo57" Clarke provided additional details about the origins of this year's badge design, as well as the decision to revert back to a non-electronic badge for Def Con 21. Hackers are encouraged to mingle and network by comparing each other's badges and working together to make sense of the various clues embedded in each board.

Attendees find ways to gather data from each unique PCB badge while meeting their fellow hackers. (Credit: Photo by Eddie Cho)

In addition to regular "human" attendees, staff and press also have their own uniquely designed badges to encourage meet-ups with other participants and exploration of the convention grounds for other related clues. For example, attendees are frequently seen gathered around the floor art that graces the hallways in between tracks, while searching for clues or hints. Others are connecting lanyards or documenting each unique badge they encounter and running Javascript codes to decipher numbers via ROT5, ROT13, and other algorithms in hopes of getting closer to solving the mystery.

I'm sure after a couple more drinks, late night music concerts, and sleepless coding sessions, the answers will come in due time.

Even lanyards provided at the conference hold clues to understanding enigmatic codes at Def Con. (Credit: Photo by Eddie Cho)