Abstract: In today’s world use of social networking sites are increased. Thus many users trying to create multiple bogus identities to compromise the running of the system. It is harmful to social network user. There are many methods available to solve bogus identity problem. Sybil means multiple bogus identities in social network. Sybil attacks are one of the well-known and powerful attack against online social network. Sybil users propagate spam or unfairly increased the influence of target user. Here we propagate Sybil defender mechanism to prevent the Sybil user to enter in the social networking site.to test we design a basic Facebook module and apply this Sybil defender mechanism to check proper working of Sybil defender. Sybil Defender first detects the Sybil user and prevent user from login into system.
Keywords: Sybil, Sybil defender, Sybil attacks