TankTread

Tanktread is a way to describe an efficient movement of people at a keysigning.

It is described here: http://woozle.org/~neale/papers/tank-tread.html (with pretty javascript on another version here: http://woozle.org/~neale/tmp/tanktread.html ). Note that these pages also describe a now-defunct keysigning protocol proposal. This page is only interested in the way people move.

So: currently it is advised that people use a 'folded line' method.

• http://www.keysigning.org/methods/adhoc
• http://keysigning.org/methods/sassaman-efficient

“	everyone forms a long line in the same order as their keys appear in the list. The head of the line then folds back on itself and the participants moving back along the line inspect the ID of each participant standing still	”
—http://keysigning.org/methods/sassaman-efficient

This is a O(2n) process.

Tanktread is O(n)

The layout is the same, but it's a loop instead. The loop slowly rotates, stopping to sign in pairs for each person in turn. Instead of one "fold", there is a fold at each end, and the ends join to become a loop. Everyone finishes at the same time.

It should take less room than folded line, and also less time, albiet at the cost of a slightly more complex initial setup.