Privacy on the Blockchain: Unique Ring Signatures
This work addresses privacy concerns for blockchain users by providing a practical, deniable anonymity solution, though it is incremental as it builds on existing ring signature concepts.
The paper tackled the problem of implementing privacy on the blockchain by introducing a unique ring signature scheme compatible with existing systems like Ethereum, resulting in the first implementation using secp256k1 for easy integration as a smart contract.
Ring signatures are cryptographic protocols designed to allow any member of a group to produce a signature on behalf of the group, without revealing the individual signer's identity. This offers group members a level of anonymity not attainable through generic digital signature schemes. We call this property 'plausible deniability', or anonymity with respect to an anonymity set. We concentrate in particular on implementing privacy on the blockchain, introducing a unique ring signature scheme that works with existing blockchain systems. We implement a unique ring signature (URS) scheme using secp256k1, creating the first implementation compatible with blockchain libraries in this way, so as for easy implementation as an Ethereum smart contract. We review the privacy and security properties offered by the scheme we have constructed, and compare its efficiency with other commonly suggested approaches to privacy on the blockchain.