Open problems in cross-chain protocols

Abstract: Blockchain interoperability is a prominent research field which aims to build bridges between otherwise isolated blockchains. With advances in cryptography, novel protocols are published by academia and applied in different applications and products in the industry. In theory, these innovative protocols provide strong privacy and security guarantees by including formal proofs. However, pure theoretical work often lacks the perspective of real world applications. In this work, we describe a number of hardly researched problems which developers encounter when building cross-chain products.