Blockchain interoperability is one of the major challenges that has sprung up with the advancement of blockchain technology. A vast number of blockchains has been developed to aid in the continuous adoption of blockchain technology. These blockchains are developed without a standard protocol, therefore making them unable to interoperate with other blockchains directly. In this paper, we present a framework to enable blockchains to interoperate in a decentralized setup. This framework maintains the decentralized property of blockchains. Additionally, an encryption of data is employed in the transfer of data between blockchains with hash-based verification ensuring the integrity of data transferred. Light client verification, based on Simplified Payment Verification, is used as a final security measure to ensure only valid transactions go through consensus to be appended to the destination blockchain. A peer-to-peer network setup modified for use in the proposed framework is also presented. The peer-to-peer setup is tested and compared with a single client-server setup to determine the computational impact it will have when implemented.
Keywords: architecture; blockchain gateway; data integrity; heterogenous; interoperability; peer-to-peer.