A Protocol for On-Chain Tenders

Blockchains offer the possibility to describe and implement processes and interactions between actors through code that can be publicly inspected, and which can be executed in a transparent and guaranteed way, without resorting to the collaboration of third party guarantors.Although transparency, together with non-censorship and non-interruptibility, are characteristics that can endow unprecedented trustworthiness to the processes implemented, in many cases they risk clashing with the privacy requirements or, more specifically, with the need to control read data access.In this work we deal with a general category of processes and interactions of importance in different sectors such as procurement: auctions and tenders. If on the one hand it is important that the widest possible audience can be convinced of the correctness of a tender, on the other it is possible that some information must remain private, such as the value of the offersIn this work we present an auction / tender protocol which on the one hand publicly guarantees the fairness of the tender, and at the same time allows to keep bids private. We also present an implementation on Ethereum Virtual Machine (EVM) environments, with which we can make quantitative cost considerations.