Poster: Towards Blockchain Transaction Privacy

Blockchains allow users to transfer money securely to possibly unknown and untrusted counterparties, without requiring a trusted intermediary. Transactions contain the value being transferred, and sender and recipient identifiers (known as addresses) in the clear, meaning that although onchain addresses are unlinked from off-chain identities, monetary movements are easily traceable. We explore methods offering transaction privacy, which include ring signatures, with which users can produce a signature that verifies against a set rather than an individual public key, and combine with stealth addresses. We construct a scheme that is compatible with current blockchain platforms, but unlinks sender and recipient address pairs in a way that payee addresses are unknown even to the payer of the transaction in question.