Sybil Attack - Reading Assignment

Bitcoin Attacks
#61
  1. The general idea of a sybil attack is to represent multiple identities in order to gain access and be “trusted”
  2. The attack can occur within a voting system in which the sybil attack can represent multiple identities and gain majority vote in a decision.
#62
  1. To create multiple personalities. Having several identities in a P2P network can allow undue influence in the working/consensus of a network.
  2. When it is easy to create multiple IDs in a network, a bot-net can literally create tons of identies that can all vote/pursuade the network in their direction. This can be mitigated by using some kind of identity verification system in the network. POW can make sybil attacks more expensive for the perpetrator.
#63

  1. A Sybil attack is when a single bad actor creates multiple identities to create false reputation in order to influence the victim to the attacker’s advantage.

  2. When a node maintains its connection to the same nodes for a long period of time, the chances of a Sybil attack are increased. Nodes should make a habit of connecting with different nodes after a period of time to reduce the risk.

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#64

  1. The general idea of a sybil attack is to manipulate functions such as voting inside a peer to peer network, by creating an enormous amount of identities per entity, that overwhelm the network and gain a lot of voting power.

  2. If it is easy and cheap to create multiple accounts inside the network it can be an easy target for sybil attacks. If there is is no authority checking if one entity really is only one identity.

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#65

1.In a Sybil attack , the attacker subverts the reputation system of a network service by creating a large number of pseudonymous identities and uses them to gain a disproportionately large influence. It is named after the subject of the book Sybil , a case study of a woman diagnosed with dissociative identity disorder.I know one woman :slight_smile:

  1. Attackers may be able to out-vote the honest nodes on the network if they create enough fake identities or Sybil identities. They can then refuse to receive or transmit blocks, effectively blocking other users from a network.
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#66

  1. To create multiple nodes or identities to trick the network into believing you are more than one person, and giving you more influence over the p2p network.

  2. If mass creation of new identities is too cheap the system is vulnerable to sybil attacks.

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#67
  1. In a Sybil attack, the attacker subverts the reputation system of the network by creating a large number of pseudonymous identities and uses them to gain a disproportionately large influence.
  2. The vulnerabilities of a reputation system to a Sybil attack depends on how cheaply identities can be generated (PoW makes it quite expensive), the degree to which the system accepts inputs from entities that do not have a chain of trust linking them to a trusted entity, and whether the reputation system treats all entities identically. In a cryptocurrency network, the creation of multiple nodes might allow to acquire monopoly of the verification process of transactions.
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#68

-A sybil attack is when one or multiple persons tries to take over a network by creating multiple false identities. These identities can be nodes or accounts. If these false identities fool the network the person gains control over the network and can outvote, reverse transactions, or change the rules of the network.
-A network that doesn’t have a strong consensus algorithm would allow an individual to easily overtake the network. PoW, PoS, and DPoS make it very impractical for this to happen. The computing power it would take would be too much for any one individual.

#69
  1. Use fake entities to suggest real participats on a network and therefore be able to influece it.
  2. If there is no user verification set up.
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#70

  1. What is the general idea of a sybil attack?
    The Sybil attack in is an attack wherein a is subverted by creating multiple identities.

  2. What deficiencies within a system (such as a cryptocurrency network) can allow a sybil attack to occur?
    They are able to create multiple identity to link in 1 acc and hack it. In peer-to-peer networks, the identity is used as an abstraction so that a remote entity can be aware of identities without necessarily knowing the correspondence of identities to local entities.

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#71

1.A node gets fed all bad information by all it’s peers being corrupt
2.Lack of changing peers

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#72

  1. It means on peer to peer network more than one identity can corresponded to a single entity.

  2. With the support from these bad actors, the influence attributed to a single entity can be blown out of proportion, and this can allows that entity to manipulate data, and release fake news that appears credible. Or if voting system is attacked the more identities can have more votes and can influence the result of the voting. Another sample if you have a system where yo can buy only limited amount of shares or other products than attacker can gain over the limit of those products.

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#73

Glenn_CostaRica

1. What is the general idea of a sybil attack?
The name “Sybil” comes originally from a famous case study of a woman – Sybil Dorsett – diagnosed with a psychiatrical condition called Dissociative Personality Disorder (DPD) where the patient had a severe problem of experimenting multiple personalities. The idea of a Sybil attack comes from this metaphor: being only one actor but appearing as many actors before other people, and using this multiplicity of identities in order to obtain some benefit. Basically, a Sybil attack consists of the actions of one single person or one organization who manages to launch many accounts – as many as possible – or many nodes in a computing system resulting in the possession of an immense centralized power equivalent to that of a large number of legitimate participants of the network. As this single actor now counts for many legitimate users inside the system, this Sybil attacker can use his numerical superiority to outvote good users – good nodes – on the network. The basic weapon of a Sybil attacker is, then, the eventual capacity to cast more votes than all the rest of good actors together. The use of the extra power for selfish purposes and the eventual harming for regular users of the system takes place in most cases. One more possibility that does not require that the attacker gains a high level of domination over the entire network, is the case in which the attacker wants to direct the evil actions against one or several good actors, by creating a lot of nodes around the good user. If the good user ends up being connected only to nodes of the perpetrator, then, this good user might be tricked by the bad hacker. For the good user here, the real Blockchain becomes invisible.

2. What deficiencies within a system (such as a cryptocurrency network) can allow a sybil attack to occur?
In the case of a Blockchain, like any of the open and public Blockchains that run cryptocurrencies, a successful Sybil attack represents the potential capacity of a malicious attacker to seize control over the network, to deny transaction requests, to act as an obstacle for block propagation, to block users completely, to insert illegitimate transactions, to revert already approved transactions and change historical records of the ledger, as well as many other lethal actions. In the case of a more local Sybil attack where the plan is only to surround one good node and trick this node in favor of a bunch of fake nodes, the consequences can be devastating for the victim. It has been studied deeply how, in cryptocurrencies that use Proof of Work for network consensus, one attacker usually needs to control at least 51% of the nodes if the objective is to take control of the entire network, which is closely related to the particular type of pernicious domination known as 51% attacks. Through a 51% attack, rewriting the history printed on previous blocks and double-spending is possible. The local case where a bunch of fake nodes damage one or a few good nodes, takes a lot less strength. Therefore, not having a powerful consensus algorithm that can adapt to new conditions or not having enough number of good nodes in the system, can be lethal for a PoW cryptocurrencies. In other kinds of networks, like Proof of Stake blockchains, the case is similar: the lower the stake barrier is, and the smaller the number of good stakers is, the more exposed the blockchain is too.

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#74

Really Glenn, thank you for that amazing answer! i will repeat it every time i see one, its always a pleasure to read your answers! all of them are so well documented! :heart_eyes:

Carlos Z.

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#76

1.-
It is a way to gain influence in a group by generating no real entities but identities.
This way the attacker can use that bigger influence to manipulate the decisions of the group.
Sounds familiar in Mexico, an example is people trying to create new parties (politics) attaching to its documentation a set of signatures of people that doesn’t really exist.

In the crypto environment the consensus is printed in many aspects, from the one that is used to take decisions about the protocol until the very block approval. This kind of attack is dangerous in bitcoin but guess that is not quite probable.

2.-
The problem is illustrated by a logic problem called Byzantine Generals’ Problem, which in resume establish the scenario on which a network needs to agree on its decisions. It demonstrates that the network is fault tolerant only if at least 2/3 of its nodes are honest.

This kind of attacks are addressed by the consensus algorithm on which the cryptocurrency network is based on, and the most common implementations of those algorithms are Proof of work and Proof of Stake.

In the case of Bitcoin, while the protocol prescribes the primary rules of the system, the PoW consensus algorithm is what defines how these rules will be followed in order to reach consensus (for instance, during the verification and validation of transactions).

So, if a crypto currency network doesn’t implement a good way to proof that real entities are participating in the decision making and force the nodes to be honest, then the network is susceptible to this kind of attack.

Taken from

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#77

  1. A Sybil attack is where an attacker creates multiple identities to appear as if they are actually many different nodes on the network. The attacker then uses these identities to subvert a networks reputation system. On a peer-to-peer network an attacker could for example use these multiple fake nodes to have a disproportionate influence on the network (e.g. via unduly influencing voting on a network).

  2. The following set of deficiencies can allow a Sybil attack to occur:
    i) If it is cheap to create new nodes and participate in the peer-to-peer network (e.g. to become a cryptocurrency miner),
    ii) if there is no chain of trust linking any particular node to a trusted entity (either directly or indirectly),
    iii) if the networks reputation system treats all nodes the same (rather than having some distinguishing ranking system).

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#78

  1. A sybil attack is focussed on a peer to peer network when one identity tries to influence the network by masquerading as multiple entities.

  2. They type of voting system it uses, proof of stake is potentially hazardous, cost of creating identities.

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#79
  1. What is the general idea of a sybil attack?

An attack by creating large number of pseudonymous. it an attack subverted by creating multiple identities. Used to change voting outcomes

  1. What deficiencies within a system (such as a cryptocurrency network) can allow a sybil attack to occur?

An adversary may present multiple identities to a peer-to-peer network in order to appear and function as multiple distinct nodes. its easy to create a user in BTC

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#80

  1. What is the general idea of a sybil attack?
    To create multiple identities and therefore acquiring a disproportional level of control of the network.

  2. What deficiencies within a system (such as a cryptocurrency network) can allow a sybil attack to occur?
    The peer-to-peer structure itself creates a situation where more than one identity can correspond to one entity. Thus the cheaper an identity can be generated, the more vulnerable the system gets.

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#81

1.What is the general idea of a sybil attack?

Within a reputation system, an attacker creates a multitude of identities that sway influence in the favor of the attacker on the system.

2.What deficiencies within a system (such as a cryptocurrency network) can allow a sybil attack to occur?

When it is easy to create multiple identities (low cost).

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