Registers distributed
Often seen as the solution to all problems, distributed registry technology is both fascinating and worrying. While it is undeniable that distributed registries have many advantages, they are not miracle cures either. Before adopting them, it is essential to understand the main advantages and disadvantages.
Let us first explain how a distributed registry works. A community of members shares a registry, each of which has an identical copy of the others. If a member wants to add an item to the registry, he suggests an entry to the other members for approval. One of them will have to validate this entry before distributing it to the whole community. Each member then sees his or her registry completed with this item. The technology implemented guarantees the identity of the registers distributed to each member at all times and a unique sequencing between entries (i.e. the blockchain). This system is based on the use of cryptographic hash functions.
The main interest of distributed registries is twofold: decentralisation of control and the inviolability of the registry. In a traditional system, any modification of a registry is subject to the approval of an authorised agent, with certain constraints: agent availability, processing time and costs, registry integrity and agent-dependent system access. These constraints are eliminated, or largely reduced, by decentralisation without jeopardising the sanctity of the registry: no one has the ability to modify the history of the registry alone, whose elements are sequenced and distributed among all members.
Distributed registers also have disadvantages, mainly related to their own characteristics: the absence of an agent and their distribution. The binding action of the agent to modify the history, or even to forbid or cancel an entry, is not necessarily undesirable. By its role, it guarantees the functioning of the system, can arbitrate and be made responsible. An algorithm has no opinion or conscience. The distribution of the register transmits the full history to all members. If an account holder can be identified, then the full details of all entries he or she has made will be known, without any prescription.
There is a huge variety of distributed ledgers, not limited to Bitcoin alone: public or private, participatory or governed, information or program-based, etc. The massive deployment of this technology is only just beginning and the possible areas of application are very numerous. However, it seems premature to bury all centralized registries and their agents.
https://fr.wikipedia.org/wiki/Blockchain
http://www.oecd.org/daf/blockchain/ (English)