Source: AOS Community Twitter
After years of development, public chain has entered the second half. More and more opponents appear on the competition track, including several transaction platforms ranking Top 10 in the world who declare to march into the area of public chain. Tough competitors are adding excitement to the second half of public chain. Days during the first half of public chain when performance and usability were competed for are over. Coming to the second half, the areas to be competed for would be vertical area and implementation of ecological application.
AOS public chain aims to be №1 in the area of privacy public chain. Then you may ask, what’s the basis of AOS being №1?
First let’s take a look at its achievements. AOS is the fastest privacy public chain in the world to support smart contract, the first public chain in the world to support zero knowledge proof programming and the leading public chain in the world to support the issuance of privacy digital assets. Meanwhile, AOS is known to the media as “development platform of private mini program” and “private EOS”.
AOS aims to launch a public chain which inherits high performance and high scalability while at the same time protects users’ privacy. Next, I’ll introduce AOS to you in detail step by step.
I. Introduction to Performance
Peak TPS of AOS can be as high as 10000, and the figure is constantly improving. Currently, the development trend of public chain is no longer measured by a single high TPS. Just like a newly-built highway, support for high speed and heavy traffic is no longer everything. Cross-regional economic development, ecological protection, cultural exchanges and strategic use of highway are also very important.
The same is true with AOS. While protecting the high standard and performance of the industry, AOS is also exploring more application value to be created in a large scale.
AOS Consensus Mechanism
AOS adopts DPOS+PBFT consensus mechanism, or Delegated Proof-of-Stake+Practical Byzantine Fault Tolerance. These two consensus mechanisms are believed to be not unfamiliar to many users. What the old generation of popular public chain, EOS, adopts is DPOS mechanism. In this regard, AOS is similar to EOS.
Early consensus mechanism of blockchain is centered on POW. Later on, the appearance of POS, which is as good as POW, paved the way for diversified development of blockchain consensus mechanism. DPOS is evolved from POS.
DPOS is the product under the need of public chain for performance improvement. Hash rate is not needed to solve complicated math problems. Rather, holders in the community are required to collectively choose work nodes for block generation and verification. These nodes will do their job within the framework of rules in an orderly way. For example, sequence of the producer is randomly assigned, blocks that aren’t produced in sequence are invalid, shuffling happens once in a cycle, and original sequence shall be disrupted.
AOS sets 21 nodes, which greatly improves work efficiency of the main net. These nodes will be chosen based on the voting result of AOS community. Nodes at work would receive bonus, while nodes that do evil would be eliminated through voting by the community, which ensures high efficiency of the mechanism and fairness.
While high efficiency and fairness is ensured, PBFT (Practical Byzantine Fault Tolerance) is embedded to enhance the security and stability of the main net.
PBFT requires common maintenance of a state and concerted action taken by all nodes. The figure above is PBFT protocol communication mode. Every request from the client needs to go through five stages and could only be executed after an agreement is reached on the server through adopting twice the method of pairwise interaction.
1) Request Client C sending the request sends the request to the major node. Here it refers to node 0;
2) Pre-Prepare After receiving the request from C, node 0 starts broadcasting and spreads to node 1, 2 and 3;
3) Prepare After receiving the request, node 1, 2 and 3 record and broadcast again, from node 1 to 0, 2, 3 and from node 2 to 0, 1, 3. Node 3 can’t broadcast due to the crash; (This is to prevent the main node from sending different requests to different slave nodes)
4) Commit During stage Prepare, if node 0, 1, 2 and 3 receive the same request exceeding a certain amount (2F, in actual use, F is the number of tolerable Byzantine nodes), then they enter stage Commit and broadcast Commit request;
5) Reply During stage Commit, if any of node 0, 1, 2 and 3 receives the same request exceeding a certain amount (2F+1), then it shall give feedback to C; after the above-mentioned process, if N ≥ 3F + 1, consistency may be solved, in which N refers to the total number of computers and F refers to the total number of computers with problems.
II. Technical Features
Privacy of AOS is the utmost important feature of the whole public chain. In the future, whether in terms of ecological development or in terms of area exploration, AOS would focus on privacy development. Privacy technology and smart contract of AOS are perfectly combined to support the issuance of privacy assets and zero knowledge proof programming. AOS will use Account model, homomorphic encryption and zero knowledge proof technology to provide underlying cryptography support to its anonymity. These cryptographic techniques would be used in the smart contract layer.
Account Model of AOS
Nearly all existing privacy public chains adopt UTXO model, which provides assets with severability and traceability. Besides, the adoption of duplicate checking method avoids “double consumption”. However, there are some problems with UTXO model: so it’s not friendly enough to the support for smart contract.
The ground on which AOS adopts Account model is this: simple asset transaction can’t meet the needs of modern business scenarios not only for business, but also for privacy and anonymity. Smart contract can provide such capabilities: we can realize various needs in the contract. The implementation logic of account model can be seen in the table below:
Of which Owner is mainly used to manage the change of other permissions, such as modification of Active’s corresponding Keys; while Active permission, upon creation, is used to conduct transfer and other contract operations, which means if you want to transfer AOS, you need Keys under Active to sign this transaction.
Homomorphic Encryption of AOS
Homomorphic encryption is an encryption scheme able to conduct mathematical operation even under cyphertext state.
Encrypting data is a common method to protect data privacy, such as your balance information. However, the commonly used encryption algorithm can’t compute data under encryption state. With homomorphic encryption, balance information can be encrypted, and transfer and collection can also be encrypted. In this way, the privacy of your transaction information could be protected.
Only by encrypting data can users be assured to put data on blockchain. Meanwhile, only by encrypting data with homomorphic encryption technology can data providers provide service to users. Therefore, in front of two contradictions of data privacy and service provision, homomorphic encryption is the best solution. We will provide various homomorphic encryption solutions for users to choose different business scenarios.
Zero Knowledge Proof of AOS
Zero knowledge proof is becoming more and more common in the area of blockchain encryption. Ethereum version 2.0 listed this summer will add this technology.
For the specific theoretical design of AOS zero knowledge proof, we tentatively propose the following solution for AOS zero knowledge proof transfer. 1) A gives B the AOS zero knowledge proof to prove the transfer. A needs to give two parameters, Pub_Key and Prv_Key, to generate zero knowledge proof evidence AOSP_π through logical processing in the contract given by AOS. That is to say, A provides the value of hash token α, namely token ID, public key of A and 32-bit random value (used to provide the uniqueness of acceptance token) to finally generate AOS zero knowledge proof intermediary token asset Z_A.
Such implementation method of zero knowledge proof is original by AOS development team. Due to the complexity of technology, only one of the implementation steps is listed for the time being. More details can be found in White Paper released by AOS.
III. Application Level
High performance structure and privacy feature of AOS bring with it a bright future to compete in the second half of public chain. The currently popular Defi concept is particularly suitable for the development of ecology on AOS.
Highly private Defi product can be created based on AOS, such as private lending. Traditional lending requires a large number of data or identity recognition as the credential of the transaction between the borrower and the lender, and some data may also be uploaded to the credit system. Such form of matching is always designed from the perspective of B-end, thus ignoring the experience of C-end users.
Such traditional lending method is a strong risk control method designed to ensure users’ collection rate. After blockchain smart contract solves the credit problem, the feeling of C-end lending users becomes important. The identity privacy, loan amount and use of loan users should be protected. Such protection is not the centralized protection of data retention and reclosing. Rather, it is realized through zero knowledge proof technology in the closed-loop logic realized on the whole business to avoid leaving privacy information in the process.
Company options can be issued based on AOS. Many start-up companies would motive their employees with options, but as with the salaries of employees, the options held by each employee are confidential. And in many cases, employees do not receive the final realizable options when they leave midway or organizers change their mind.
AOS will provide solutions for these traditional companies at the technical level. Companies adopt anonymous option scheme of AOS, issue company options to employees on AOS and use AOS anonymous technology to protect user privacy and ensure the freedom and effectiveness of holding.
Similar applications are numerous. In the future, AOS will explore more application models and business models with enterprises and government agencies.
IV. Basic Information of AOS
Official Website: www.aos.plus