Author: ZmnSCPxj 2021-03-16 02:11:15
Published on: 2021-03-16T02:11:15+00:00
In response to a question about the security of Conjoin and Wasabi wallet, ZmnSCPxj explains that CoinJoin transactions are secure and cannot be damaged by third parties. This is because each input must be signed, and when providing its signature, each entity verifies that its provided address exists in some output first before signing out its input. The provided signature requires all the inputs and all the outputs to exist in the transaction. Therefore, it is not possible to take a "partial" signature for this transaction, then change the transaction to redirect outputs elsewhere. Third parties involved in popular implementations of CoinJoin (such as the coordinator in Wasabi) are nothing more than clerical actuaries that take signatures of an immutable document, and any attempt by that clerical actuary to change the document also destroys any signatures of that document, making the modified document (the transaction) invalid.Regarding the prevention of fraud, ZmnSCPxj explains that it simply requires that all addition is validatable, but it does not require that the actual values involved are visible in cleartext. Various cryptographic techniques already exist which allow the verifiable addition of encrypted values ("homomorphisms"). At the same time, if one wanted to voluntarily reveal the numbers involved, they could do so and any validator can check that the points recorded on the blockchain match with what was claimed. For the prevention of fraud, we should strive to be as transparent as little as possible, while allowing users to voluntarily reveal information.
Updated on: 2023-06-14T18:21:45.256591+00:00