Paper #: Week 12 Paper 1 
Title: The Sybil Attack

(1) Problems
This paper is a overview of Sybil Attacks. It explains in clear terms what the term 'Sybil Attack' means and shows that without the presence of a 
logically centralized authority, which certifies identities of entities in a peer to peer system, Sybil attacks can always take place.  

(2) New Idea and Strengths
i) The paper is very well written. It gives a comprehensive overview of the problem - the Sybil Attack and explains that without having a trusted 
centralized authority which manages identies, it is always possible to forge multiple identities.
ii) The formal model that the author presents is a pretty accurate description of a normal peer to peer network and thus is a correct backdrop for 
the author's theory that a trusted centralized authority is required.
iii) The results section is well thought out. It explains what the three potential sources of identities and presents lemmas to prove his claims.
iv) This paper is structured differently than others that we have studied in this class. This paper does not have experimental results to back its 
claims - instead it proves its claims theoretically. 

(3) Weaknesses and Extensions
i) Though I understand that the author's objective is to discuss the Sybil attack - the paper just claims that a trusted centralized repository is 
needed to prevent Sybil Attacks but does not expand more on how the trusted centralized repository would work.
ii) An extension to this paper might be to suggest and expand on how the trusted centralized repository would work. 


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