Blockchain databases are storage systems that combine properties of blockchains and databases like decentralization, tamperproofness, low query latency and support for complex queries. Blockchain databases are an emerging and important class of blockchain technology that is critical to the development of non-trivial smart contracts, distributed applications and decentralized marketplaces.

Designing a flexible, yet secure communication infrastructure has long been an elusive goal. Most of the proposals that seek to address the problem of flexibility have opened up the system for new forms of attacks. In this paper, we consider one particular proposal, i3 [2], a flexible indirection infrastructure that provides natural support for a multitude of communication primitives such as multicast, anycast and mobility. We systematically identify the attacks on i3, and propose techniques that address the security problems without sacrificing the flexibility that i3 offers. Our techniques, ranging from cryptographically constraining the forwarding entries to challenge-based mechanisms for inserting forwarding entries, while being simple, both conceptually and to implement, make most of the attacks provably hard. We believe that this paper represents an important step towards designing communication infrastructures that are both secure and flexible.

Attempts to generalize the Internet's point-to-point communication abstraction to provide services like multicast, anycast, and mobility have faced challenging technical problems and deployment barriers. To ease the deployment of such services, this paper proposes a general, overlay-based Internet Indirection Infrastructure (i3) that offers a rendezvous-based communication abstraction. Instead of explicitly sending a packet to a destination, each packet is associated with an identifier; this identifier is then used by the receiver to obtain delivery of the packet. This level of indirection decouples the act of sending from the act of receiving, and allows i3 to efficiently support a wide variety of fundamental communication services. To demonstrate the feasibility of this approach, we have designed and built a prototype based on the Chord lookup protocol.

Attempts to generalize the Internet's point-to-point communication abstraction to provide services like multicast, anycast, and mobility have faced challenging technical problems and deployment barriers. To ease the deployment of such services, this paper proposes an overlay-based Internet Indirection Infrastructure ( I3) that offers a rendezvous-based communication abstraction. Instead of explicitly sending a packet to a destination, each packet is associated with an identifier; this identifier is then used by the receiver to obtain delivery of the packet. This level of indirection decouples the act of sending from the act of receiving, and allows I3 to efficiently support a wide variety of fundamental communication services. To demonstrate the feasibility of this approach, we have designed and built a prototype based on the Chord lookup protocol.