On the combined application of CBDC system and blockchain

Ljzn 2022-04-03 16:11:11 阅读数:225

combined application cbdc blockchain

CBDC Introduce

from 2016 Since then , Many countries, including China, have begun to build their own CBDC ( Central bank digital currency ) System . So what is CBDC, One sentence summary , This works in conjunction with the entity's cash , Issued by the central bank , Cash in digital form , It can give the cash system higher security , And more convenient for the central bank to manage .

CBDC Can be divided into public oriented , And for financial institutions . The former, such as the digital RMB that China can already use APP, After downloading, you can use it in the store . The latter can be used for real-time settlement between banks , Improve the efficiency of cross-border transfers .

CBDC The main needs of can be summarized as :

  1. Controllability

The central bank should issue 、 monitor 、 Transfer 、 The ability to freeze assets .

  1. integrity

As a cash ledger , Historical transfer records should have the characteristics that cannot be tampered with , Ensure data integrity .

  1. Verifiability

In the scenario of cross-border transfer , Both parties to the transaction shall be able to independently verify whether the transfer is true and effective .

meanwhile , Central bank digital currency can help economic development in these aspects :

  1. It's easier to identify counterfeit money than real money .
  2. Prevent financial institutions from becoming regulatory black boxes .
  3. Facilitate cross-border settlement business .
  4. It is conducive to combating transnational crime , Within the framework of mutual trust , National regulators can cooperate , Verify the legitimacy of each transaction , And freeze certain transactions .
  5. Protect the privacy of citizens' daily transactions from infringement .

Blockchain Introduction

The history of blockchain can be traced back to 1991 year , Scientists from Bell Labs Haber and Stornetta Published papers “ How to time stamp electronic documents ”. Through the hash digest algorithm ( Hereinafter referred to as hash ) And Merkel tree structure , Connect massive files to a short piece of data , Called Merkel root . Then we need to solve how to connect Merkel to a certain point in time . stay 1996 year , They were founded suerty.com company , Using this technology : Regularly publish Merkel root to the latest issue 《 The New York times 》 In the international newspaper . such , Through the huge circulation and audience of newspapers , So that Merkel's timeliness and integrity can be guaranteed . The company's electronic document timestamp scheme has been successful , Including Xerox 、 Big companies such as Samsung have become their customers .

Time to 2009 year , The person named Nakamoto released the bitcoin white paper :“ The currency -- A point-to-point electronic cash system ”. In the white paper , Nakamoto quoted 3 From Haber and Stornetta The paper of , It is enough to explain the technology inheritance relationship between them . Bitcoin also uses the Merkel tree structure to connect transactions . The key innovation is the use of proof of workload instead of newspapers , To achieve Merkel's distribution .

Due to the code openness of bitcoin technology itself , All kinds of similar projects are not required , As a result, the blockchain industry is mixed 、 Good and evil people mixed up , A considerable number of projects carry out Ponzi fraud in the name of blockchain , We should also polish our eyes , Improve discrimination , Avoid becoming a tool for endorsing fraudulent projects . that , Is there a simple standard to judge the quality of a blockchain technology ? The answer is yes , First, transaction throughput , Also called TPS(Transaction Per Second), Second, the cost of each transaction .TPS The higher the , Prove the scalability of the system 、 The better the usability ; The lower the transaction cost , It is proved that the more efficient the energy utilization of this system is . conversely ,TPS The lower the , The higher the service charge , It shows that the less efficient the system is , When it's low to a certain extent , This system may be regarded by some countries and regions as a backward industry that should be eliminated . Although due to the buying of investors , Their prices soared , Miners will also gain a lot of wealth , But in fact, these systems do not create value matching their price .

Now there is a view , I think blockchain technology must be inefficient . In fact, this view is untenable , First , The binary tree structure of Merkel tree , Determines the logarithmic relationship between the number of leaf nodes and the number of tree layers , 100 million leaf nodes , It only needs 27 The tree on the first floor can accommodate . let me put it another way , Verify whether any of the 100 million leaf nodes belongs to a tree represented by Merkel root , Just get along the way 27 One hash data is enough . secondly , Due to the openness and competition of workload Certification , It is bound to lead to “ dig ” The scale of the industry 、 Centralization . Huge data center mines will gradually replace illegal scattered mines , The number of these data centers is bound to be small , The network connection between them must also be very professional . Distributed system , The number of nodes is inversely proportional to the difficulty of network consistency , Fewer specialized nodes , It effectively improves the efficiency of network transaction processing .

Technology Architecture

So blockchain technology is CBDC What role can it play in the architecture of the system ? Before we go into this question , We should first understand how electronic data is managed in ordinary banks . According to the report ,2020 In, the South African post bank suffered huge losses due to the leakage of root key , According to the source , Although the bank lost only... Because of the resulting fraud 320 Thousands of dollars , But because master key Leakage of , The bank will have to report the loss and replace 1200 Ten thousand bank cards , And this will cost 5800 Thousands of dollars .

Banks are highly dependent on PKI(Public Key Infrastructure) And CA(Certification Authority), This leads to the root key becoming the lifeblood of bank data security , Once the root key is leaked , All previous signature data will face great risks .

On the other hand ,PKI In the system , The root key needs to be changed regularly , And this process is often very cumbersome and primitive . For example, in DNSSEC ( One kind is right DNS A security scheme for signing data ) In the system , It needs to be replaced at regular intervals KSK(Key Signing Key), The specific way is in the case of webcast , Destroy the memory card with the old key with scissors , To prove that this key has been completely destroyed .

Blockchain has creatively designed a new security model , That is, no longer rely on any signature algorithm to ensure data integrity . Some friends may say , Using bitcoin transfer is not necessary ECDSA Sign ? Yes , But when using blockchain to verify the timestamp of a transaction , No signature or key is required . Connect blockchain with PKI A combination of systems , You can get the following benefits :

  1. Tamper proof historical data .

Even if the key has been leaked , Because blockchain WORM(Write Once Read Many) Characteristics , Attackers can't forge past timestamps .

  1. Can revoke a specific certificate

By sending a new transaction , The certificate can be modified in near real time , Including abolishing .CA And users of certificates can flexibly formulate the use strategy of certificates , Including creating time limited valid certificates through smart contracts such as time locks .


As a defense , We first discussed two key indicators to measure the advantages and disadvantages of blockchain system -- TPS And transaction costs ; secondly , We discussed the internal PKI The importance of the system and its potential safety hazards ; Last , We propose to combine blockchain technology , How can we eliminate these hidden dangers , And help build CBDC System .

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