Distributed Verifier - Smart Contract for verifying ECDSA signatures on multiple curves

The blockchain is an innovative technology based on a distributed ledger shared between all nodes involved in the network. The nodes communicate with each other and manage data, which are transactions, according to a specific communication protocol. The blockchain allows transactions to be validated and stored in the distributed database shared across all the decentralized nodes. The transactions are public so that anyone can retrieve and verify them. Additionally, the transactions recorded in the distributed ledger are stored permanently and become immutable. The recent distributed ledger technology enables the deployment of smart contract onto the network nodes. Smart contracts are distributed apps (dApp) executed from all the nodes of the peer-to-peer network, that compute and agree on the results validating them. Every smart contract transaction requires a payment that is charged to the caller with an amount which is proportional to the complexity of the function called. The nodes use digital signatures computed over elliptic curves to verify transactions. Every blockchain employs a specific curve, for instance, Bitcoin and Ethereum use the SECP256K1. In this kind of environment is possible to verify only transactions that have a fixed structure and are signed on a specific curve. This work explores the feasibility of the creation of a smart contract able to verify the signature of a generic data calculated over multiple curves without being constrained to a specific blockchain’s curve. Although there are some challenges in implementing signature verification in this environment, this type of smart contract has been implemented and works correctly. Additionally the smart contract must be tested for compliance with NIST guidelines. Therefore, various tests have been conducted to ensure its accuracy in meeting the standards. Moreover, tests have been conducted to determine the financial cost and the time required for verification. Finally, a possible use case of the smart contract is presented, highlighting the advantages of blockchain over a centralised environment.