SciDex Whitepaper

5. Security & Sybil Attacks
The main problem in any system where reputation is involved is the threat of Sybil attacks. In a
Sybil attack, the attacker subverts the reputation system of a peer-to-peer network by
creating a large number of identities and using these identities to gain a disproportionately
large influence [15]. A reputation system’s vulnerability to a Sybil attack depends on how cheap
identities can be generated and whether the reputation system treats all entities identically
[16].
Therefore, the following mechanisms are implemented to prevent a Sybil attack:
⁃ Trusted Members - Only Trusted Members can vouch or cast votes. As stated in
3.2.2, to become a Trusted Member requires effort and tokens. Becoming a
Trusted Member is expensive for the attacker.
⁃ Security Deposits - To provide data for the MarketSpace, a data provider stakes
tokens for a probation period. The security deposit can be lost due to providing
empty or forged datasets.
Therefore, the high cost and long period of time to create trusted IDs as well as the loss of the
security deposits in escrow discourage this type of abuse.
24