Crypto Academy Week 13 | homework post for @alphafx | consensus algorithm | by @loveth01.

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Thank you professor @alphafx for this lecture. I will be choosing STELLAR CONCENSUS PROTOCOL (SCP) for this homework.

What is the Stellar consensus protocol?

Stellar Consensus Protocol is the first secure and provable realization of the Federal Byzantine Protocol. The Stellar consensus protocol, SCP, was developed based on a consensus algorithm called Federated Byzantine Agreement (FBA).

Unlike most existing methods for achieving consensus, the Stellar consensus protocol has the following four key attributes :

1 . Decentralized control
2 . Flexible trust
3 . Low latency
4 . Progressive safety

✓ As a federated Byzantine agreement, the Stellar Consensus Agreement makes sure there is safety in the face of irrational behavior, requiring only limited computing resources and reducing the barriers to entry.

✓ Flexible trust means that users can freely trust any combination of participants that they consider appropriate.

✓ progressive security. Security is based on digital signatures and hash families, and its parameters can be adjusted according to the actual situation to resist opponents with strong computing power. For example, imagine that the password length can increase as the attacker's computing power increases.

How is the new code different?

A brand new code base has been created with the following design concepts:

1 . security,
2 . simplicity,
3 . scalability
4 . interoperability
5 . multiple implementations.

The core consensus service is as simple and economical as possible.

Real-time data is stored in a standard SQL database, and the data is read by an external network service and provided to users. The long-term encrypted data will be written to the public storage service in the form of a standard XDR binary format file for downloading or mirroring. A transaction is a collection of simple operations in a variety of patterns, supporting multiple signatures and other innovative actions.

The of the Byzantine agreement is to ensure that the distributed consensus ignores Byzantine errors. "Byzantine error" describes arbitrary behavior, including irrational behavior.

The non-federal Byzantine agreement requires the system participants to reach an agreement-which means a centralized system. Every node in the network must be known and verified.
The Byzantine agreement can resist outside attackers with a large amount of computing power, but has a private list of members.

Stellar began using the Stellar Consensus Protocol (SCP), a new consensus mechanism that improved Ripple's protocol in November 2015.
The new protocol used in the Stellar consensus protocol (SCP) was developed by David Mazieres, a professor of computer science at Stanford University in the United States.

That transactions are confirmed within seconds is based on the consensus protocol rather than Stellar mining.Since it is a simple message transmission using a network, it consumes less computational power and energy.

In addition, trader assets can be transferred directly to existing fiat currency or other cryptocurrencies without the need to change to Stellar Lumen, the Stellar currency.

Stellar Concensus Protocols (SCPs) have verifiable safe properties that can optimize safety over longevity.In the event of a node disruption or malfunction, the network stops proceeding until consensus is reached.

Stellar Concensus protocol (SCP) is a method of reaching consensus using a trust network formed based on the user's direct choice of whom to trust.

Understanding Stellar Concensus Protocol (SCP) requires the concept of node, quorum, and quorum slice.

A quorum slice is a set of common nodes and a subset of the quorum to reach an agreement and quorum is an agreement that is decided and can never change.

In other words, it is a group of nodes chosen to be reliable. Users (nodes) choose what is called a quorum slice in a decentralized way, continuing to overlap, determining quorum, and reaching consensus on a particular message.

For example, node 1 and node 2 are set to not trust the bank.

Therefore, the consensus with the bank requires another quorum slice that the node can trust.
Then, when consensus is reached, a quorum is created. quorum slices and quorums are formed dynamically because not all nodes have the same configuration file.

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Stellar Network

The Stellar Network is the sum of all Stellar Cores around the world maintained by different people and organizations. Because the network is decentralized, it is reliable and secure.

All these Stellar cores (node ​​networks) agree on a series of transactions.The transaction costs as little as 0.00001 XLM.

This fee helps prevent bad actors from spamming users' network also, Stellar Network can be used to build mobile wallets, banking tools, smart devices, and everything related to payments.

Stellar Protocol

1. API Server: Horizon

Most applications used to relate with the Stellar network through Horizon which is a RESTful HTTP API server.
Horizon provides a simple way to submit deals, verify accounts, and subscribe to events.
Since it's just HTTP, a person can communicate with Horizon using a web browser, a simple command line tool like cURL, or the Stellar SDK for his favorite programming language.
It maintains Java Script, Java and Go-based SDKs for communication with Horizon, as well as community-managed SDKs for Ruby, Python, and C.

1. Stellar Core

All Horizon servers are connected to the Stellar Core, the backbone of the Stellar network. The Stellar Core software verifies and agrees to the state of all transactions through the Stellar consensus algorithm, SCP. Some instances have Horizon servers to communicate with, while others exist to add stability to the entire network.

The Stellar Consensus Protocol can be used to complete consensus without depending on any closed system to accurately store and record financial transactions that have taken place.

The Stellar Consensus Protocol is the first secure and verifiable consensus mechanism, and it also enjoys four key attributes: decentralized control, low latency, flexible trust, and asymptotic security.

The Stellar Consensus Protocol is inspired by Bitcoin which has the ability to tolerate irrational factors in a low computing power environment.

This agreement is the cornerstone of the currency's public infrastructure, and it will also make Stellar a canvas for people to paint their ideal financial services.in a nutshell, the goal is to use the Stellar Consensus Agreement to create a different situation in terms of financial inclusion. In addition to Stellar, it is hoped that the Stellar consensus protocol can make important contributions in the field of distributed systems.

thanks professor @alphafx this is my homework post.