Marking procedure at router R: let R' = BitIntereave(R, Hash(R)) let k be the number of
none-overlappling fragments in R' for
each packet w let x be a random number from [0..1) if xlet o be a random integer from
[0..k-1] let f be the fragment of R' at
offset o write f into w.frag write 0 into w.distance wirte o into w.offset else if
w.distance=0 then let f be the fragment of
R' at offset w.offset write f?w.frag into w.frag increment w.distance Path reconstruction
procedure at victim v: let FragTbl
be a table of tuples(frag,offset,distance) let G be a tree with root v let edges in G be
tuples(start,end,distance) let
maxd:=0 let last:=v for each packet w from attacker FragTbl.Insert
(w.frag,w.offset,w.distance) if w.distance>maxd then
maxd:=w.distance for d:=0 to maxd for all ordered combinations of fragments at distance d
construct edge z if d!=0 then z:=
z?last if Hash(EvenBits(z))=OddBits(z) then insert edge(z,EvenBits(z),d) into G
last:=EvenBits(z); remove any edge(x,y,d)
with d!=distance from x to v in G extract path(Ri..Rj) by enumerating acyclic paths in G
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