Post by kwinsi on Mar 3, 2023 2:25:32 GMT -5
Ateniese et al. [7] proposed the first protocol for illicit content deletion from blockchains. Their solution is simple and efficient but, unfortunately, mainly targets the permissioned setting and cannot be adapted to Bitcoin. Unlike ours, in their approach a deletion does not leave trace and goes unnoticed to users not participating in the redaction. The solution of Ateniese et al. is based on the concept of chameleon hash function, essentially hash functions endowed with trapdoors that allow to find different preimages to a given hashed value. The drawback of solutions based on such kind of cryptographic tool is that the trapdoor should be kept secret or shared among a set of authorities. In our solution instead we do not assume any set of authorities to share some secrets needed for the redaction.
Puddu et al. [8] provided a more complex protocol for dealing with redactions of harmful content. They proposed a protocol in which users can set alternate versions, called “mutations”, of their transactions that can be later activated after running an expensive MPC protocol. A request of a modification has to be approved by means of a voting procedure based on proofs of work. In their solution, only the creator of a transaction can allow modifications, thus preventing deletion of content inserted by malicious parties. The main drawback of their solution is that the ability of “mutating some content” has to be explicitly set by the miners and so malicious miners can simply bypass the mutation mechanism. Moreover, mutation of some content has a cascade effect on any subsequent transaction, thus incurring a huge performance penalty.
Deuber et al. [9] proposed a novel redactable blockchain protocol that can be integrated in Bitcoin. In their protocol, each user can propose a modification by writing the proposal on the blockchain. The redaction proposal is subject to a voting procedure based on consensus and computational power. The Deuber et al.’s proposal requires a voting procedure performed online on the blockchain whereas in our protocol each node can individually perform a deletion without the need of interaction with other nodes. Deuber et al.’s introduce “public verifiability” that in their case consists of the ability of tracing redactions. In our protocol redactions can be traced as well.
Thyagarajan et al. [10] proposed Reparo, a protocol that improves Deuber et al.’s solution with the property of “Reparaibility of Existing Content” (REC), that is the possibility of redacting or modifying blocks that are inserted in the blockchain before the software update that includes the redaction protocol is performed. As in Deuber et al., Reparo is based on expensive and interactive consensus protocols that requires several days to be run as opposed to our protocol in which deletion can be performed in few minutes. Both Thyagarajan et al. and Deuber et al. do not guarantee individual deletion, meaning that it is not possible for a single node to delete data locally without starting the voting procedure.
Florian et al. [11] proposed a different approach in which nodes do not completely validate the chain and have to trust others, while in our solution a blockchain subject to data redaction can be completely validated by each node.
Puddu et al. [8] provided a more complex protocol for dealing with redactions of harmful content. They proposed a protocol in which users can set alternate versions, called “mutations”, of their transactions that can be later activated after running an expensive MPC protocol. A request of a modification has to be approved by means of a voting procedure based on proofs of work. In their solution, only the creator of a transaction can allow modifications, thus preventing deletion of content inserted by malicious parties. The main drawback of their solution is that the ability of “mutating some content” has to be explicitly set by the miners and so malicious miners can simply bypass the mutation mechanism. Moreover, mutation of some content has a cascade effect on any subsequent transaction, thus incurring a huge performance penalty.
Deuber et al. [9] proposed a novel redactable blockchain protocol that can be integrated in Bitcoin. In their protocol, each user can propose a modification by writing the proposal on the blockchain. The redaction proposal is subject to a voting procedure based on consensus and computational power. The Deuber et al.’s proposal requires a voting procedure performed online on the blockchain whereas in our protocol each node can individually perform a deletion without the need of interaction with other nodes. Deuber et al.’s introduce “public verifiability” that in their case consists of the ability of tracing redactions. In our protocol redactions can be traced as well.
Thyagarajan et al. [10] proposed Reparo, a protocol that improves Deuber et al.’s solution with the property of “Reparaibility of Existing Content” (REC), that is the possibility of redacting or modifying blocks that are inserted in the blockchain before the software update that includes the redaction protocol is performed. As in Deuber et al., Reparo is based on expensive and interactive consensus protocols that requires several days to be run as opposed to our protocol in which deletion can be performed in few minutes. Both Thyagarajan et al. and Deuber et al. do not guarantee individual deletion, meaning that it is not possible for a single node to delete data locally without starting the voting procedure.
Florian et al. [11] proposed a different approach in which nodes do not completely validate the chain and have to trust others, while in our solution a blockchain subject to data redaction can be completely validated by each node.