Quantstamp is proud to announce that we have enhanced the security of OmiseGO’s More Viable Plasma (More VP). OmiseGO is a repeat customer of Quantstamp: their first audit with Quantstamp took place in Nov 2018 in which our security engineers reviewed More VP’s predecessor, Minimum Viable Plasma.



The OmiseGO team requested that Quantstamp answer the following questions during their security review:

Can a malicious user compromise funds from OMG network users?

Can a malicious user disrupt users ability to deposit, withdraw, or perform transactions on the OMG network?

Can users safely exit their funds in the presence of a malicious owner?

How can the existing code be improved?



Quantstamp discovered a denial-of-service attack vector and several low-risk issues in the initial review process. OmiseGO quickly responded with fixes and, as is customary in all of Quantstamp’s security reviews, Quantstamp then reviewed the suggested fixes and determined that they correctly addressed the initial vulnerabilities.



Quantstamp also found that if a plasma user has many small UTXOs, it may make withdrawing funds to Layer 1 prohibitively expensive and also leave them open to having funds stolen by malicious plasma operators. OmiseGO stated that they plan to address this by regularly combining UTXOs on the application layer.

What is Plasma?



Plasma is a Layer 2 technology in development that aims to scale Ethereum so that it can handle higher transaction rates by reducing the amount of data that is stored directly on the main Ethereum blockchain, also referred to as Layer 1 Ethereum. Plasma aims to create blockchains that exist “on top of Ethereum” that enable faster and cheaper transactions but that ultimately rely on the main chain for security.

How is More Viable Plasma different than Minimum Viable Plasma?



More Viable Plasma is designed to improve user experience. In Minimum Viable Plasma, when a user sends a transaction, their transaction is not finalized until they send a 2nd “confirmation message.” A user is only supposed to send this confirmation message once they recognize that their transaction was added to a plasma block. This additional step was required in order to secure their funds against malicious actors.



In More Viable Plasma, users no longer need to send a confirmation message in order to finalize their transaction. In order to protect users funds in this new design, the exit game was modified. More VP’s exit game can be described as the economic incentives that are built into the way users withdraw funds from Layer 2 to Layer 1 in order to discourage malicious behavior.



In More Viable Plasma, if a user wants to withdraw their funds from Plasma Layer 2 to Ethereum Layer 1, they must place a bond that can be claimed by other network participants if the user withdrawing funds is cheating the network.



In order to claim the bond, network participants must provide proof that a malicious user is attempting to withdraw funds they have already spent. This game simultaneously incentivizes network participants to look for dishonest behavior while also disincentivizing potential bad actors from cheating the network.



More Viable Plasma also included “in-flight exits.” This means that if a malicious operator refuses to add your transaction within a plasma block, users can still safely redeem their funds.



About Quantstamp

Quantstamp is a Y Combinator-backed company building the standard in blockchain cybersecurity. With a team of security experts dedicated to securing decentralized systems, Quantstamp is enabling a future of safer and more reliable blockchain applications and helping enterprise companies deploy blockchain solutions with a security-first mindset.

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