In 'The Tangle' white paper, at the beginning of Section 4, this statement is made:
- It is possible for the attacker to have a plethora of Sybil identities which are not required to approve tips.
And then Wikipedia states this regarding Sybil attacks:
The Sybil attack in computer security is an attack wherein a reputation system is subverted by forging identities in peer-to-peer networks.
What impact do Sybil identities have on the tangle when there is no reputation system?
And how can a transaction be attached to the tangle without performing any approval of the two transactions it's being connected to?