Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ToGCom: An Asymmetric Sybil Defense   Proof-of-work (PoW) is one of the most common techniques to defend against
Sybil attacks. Unfortunately, current PoW defenses have two main drawbacks.
First, they require work to be done even in the absence of an attack. Second,
during an attack, they require good identities (IDs) to spend as much as the
attacker.
  Recent theoretical work by Gupta, Saia, and Young suggests the possibility of
overcoming these two drawbacks. In particular, they describe a new algorithm,
GMCom, that always ensures that a minority of IDs are Sybil. They show that
rate at which all good IDs perform computation is $O(J_G + \sqrt{T(J_G+1)})$,
where $J_G$ is the join rate of good IDs, and $T$ is the rate at which the
adversary performs computation.
  Unfortunately, this cost bound only holds in the case where (1) GMCom always
knows the join rate of good IDs; and (2) there is a fixed constant amount of
time that separates join events by good IDs. Here, we present ToGCom, which
removes these two shortcomings. To do so, we design and analyze a mechanism for
estimating the join rate of good IDs; and also devise a new method for setting
the computational cost to join the system. Additionally, we evaluate the
performance of ToGCom alongside prior PoW-based defenses. Based on our
experiments, we design heuristics that further improve the performance of
ToGCom by up to $3$ orders of magnitude over these previous Sybil defenses.

30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
18
The categories of this paper are: econ
19
The categories of this paper are: eess
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
31
The categories of this paper are: ao-sci
23
The categories of this paper are: solv-int
25
The categories of this paper are: patt-sol
34
The categories of this paper are: chem-ph