Difference between revisions of "Blockchain"

Revision as of 13:16, 16 December 2018

Full Title or Meme

Block Chain will solve all problems, provided you have the energy of a small sun available to power it.

Context

The technology for Block Chain itself has been around for at least 20 years. These simple chain allowed non-revocable commitments by creating a series of blocks that included a collection of all of the block hashes received since the last update plus the hash of that last update. The has of the current block update is calculated and published in a public place plus being added to the next update in sequence. Thus each entry onto the block chain cannot be changed as so is immutable.

Simple Chains

Block chains were first commercialized by Bellcore which published the hash of each day's update in the New York Times.

Proof of Work

The point of proof of work is to randomize the choice for the source node for the next block in the chain. This will allow trust to be established for the case where less that 50% of the node are colluding to subvert the chain.

• The first successful block chain with distributed ledger was created by the pseudonymous S. Nakamoto^[1] which resulted in the highly popular anonymous money know as Bitcoin.
• Mark Russinovich did an interesting calculation that showed that this pow scheme is now consuming as much power as the entire country of Denmark.^[2]

Problems

• The current problem that many architects are fixated on solving relate to the concentration of user information in a small number of very large companies.
• There are some efforts to reduce the power consumption. If those work, it looks like the solution will just be some other trust framework, but with a different name. For example the proposal of Hardjono et al.^[3] goes to a resilient system like the internet, which is, of necessity, single rooted even though nearly all components can work independantly for a time, just as the internet itself functions today.

Solutions

Most of the solutions rely either on permissions for participants in the block chain process, which implies some source of trust to select the participants, or some less costly source of randomness in selecting the next node to "win" in the contest to submit the next block.^[4] Most of these solutions deriver from the Byzantine Generals' Problem which is a cryptographic solution to making decisions when the is a lack of trust among the deciders.^[5]

• Proof-of-Stake solutions use a random selection process, but maintain the value on the chain as the incentive for the selected updater to continue the chain.
• Pure Proof-of-Stake block chain systems. Also has some good comparisons against other schemes.
• ALGORAND the block chain for business contains a good collection of block chain papers.

References

1. ↑ S. Nakamoto. Bitcoin: A peer-to-peer electronic cash system. https://bitcoin.org/bitcoin.pdf, 2008.
2. ↑ Mark Russinovich Microsoft Build (2018-05-06) https://channel9.msdn.com/Events/Build/2018/BRK2507
3. ↑ Thos Hardjono, +2 Towards a Design Philosophy for Inter-operable Blockchain Systems MIT May 16, 2018 [1]
4. ↑ Zubin Koticha, Proof of Stake and the History of Distributed Consensus: Part 1, Nakamoto Consensus, Byzantine Fault Tolerance, Hybrid Consensus, Thunderella. (2018-09-04) Thunder https://medium.com/thunderofficial/proof-of-stake-and-the-history-of-distributed-consensus-part-1-nakamoto-consensus-byzantine-176e0156316e
5. ↑ Lamport, L.; Shostak, R.; Pease, M., "The Byzantine Generals Problem" (PDF). (1982) ACM Transactions on Programming Languages and Systems. 4 (3): 387-389. doi:10.1145/357172.357176