Posted by Anon on 4/1/05 12:02pm
Msg #29141

The Sybil Attack

The Sybil Attack

John R. Douceur
Microsoft Research
[e-mail address]

“One can have, some claim, as many electronic personas as one has time and energy to create.”
– Judith S. Donath

Abstract – Large-scale peer-to-peer systems face
security threats from faulty or hostile remote
computing elements. To resist these threats, many
such systems employ redundancy. However, if a
single faulty entity can present multiple identities,
it can control a substantial fraction of the system,
thereby undermining this redundancy. One
approach to preventing these “Sybil attacks” is to
have a trusted agency certify identities. This
paper shows that, without a logically centralized
authority, Sybil attacks are always possible except
under extreme and unrealistic assumptions of
resource parity and coordination among entities.