Common use of Roadmap Clause in Contracts

Roadmap. The background is given in Section 2. The model and the accountable Byzantine consensus problem are pre- sented in Section 3, and impossibility results are given in Section 4. Section 5 describes the Polygraph protocol, which solves the accountable binary Byzantine consensus prob- lem. Section 6 analyses empirically the Polygraph protocol in a geodistributed blockchain. blockchain and Section 7 concludes. An Appendix is left to the discretion of the reader. ▇▇▇▇▇- ▇▇▇ A presents the proof of the impossibility result, ▇▇▇▇▇- ▇▇▇ B presents the proof of correctness of the Polygraph pro- tocol, Appendix C presents the multivalue Polygraph proto- col that supports arbitrary values. Appendix D presents some optimizations to reduce the complexity of the multivalue Polygraph protocol. Appendix E discusses the applications of the Polygraph protocol to blockchain. Finally, Appendix F shows that a naive extension of classic blockchain consensus protocols, including PBFT, HotStuff and Tendermint, cannot make them accountable.