francesco.strazzullo@ideato.it
@TheStrazz86
https://github.com/francesco-strazzullo
https://medium.com/@TheStrazz86
https://slides.com/francescostrazzullo
Blockchain is a decentralized consensus mechanism. In a blockchain, all peers eventually come to an agreement regarding the state of a transaction.
Imran Bashir
Blockchain can be considered a shared ledger of transactions.
Imran Bashir
Blockchain is a data structure; it is basically a linked list that uses hash pointers instead of normal pointers. Hash pointers are used to point to the previous block.
Imran Bashir
Graph by Imran Bashir
Graph by Imran Bashir
David Chaum published a seminal paper in 1984 about electronic cash. The main problems that he tried to address are accountability and anonymity
Hashcash was created by Adam Back in 1997 as a system to control e-mail spam. When a user want to send an email they are required to compute a hash as a proof that they have spent a reasonable amount of computing resources before sending the e-mail.
Generate this Hash is a very demanding task, but for a normal user it's acceptable. This mechanism would instead destroy any kind of spambot because of the large volume of mails they send
While Hashcash is hard to generate is quite easy to verify. Verification is performed by the user who receives the e-mail.
Introduced by Wei Dai in 1998, it's a peer-to-peer network where money is created by solving computational puzzles such as hashcash
In 2008 Satoshi Nakamoto, a nickname for an unknown person published the paper "Bitcoin: A Peer-to-Peer Electronic Cash System".
Satoshi Nakamoto introduced the term chain of blocks. This term over the years has now evolved into the word blockchain.
In 2009 Bitcoin goes live
Graph by Imran Bashir
Distributed systems are a computing paradigm whereby two or more nodes work with each other in a coordinated fashion in order to achieve a common outcome and it's modeled in such a way that end users see it as a single logical platform.
Imran Bashir
any distributed system cannot have Consistency, Availability, and Partition tolerance simultaneously
is a property that ensures that all nodes in a distributed system have a single latest copy of data
means that the system is up, accessible for use, and is accepting incoming requests and responding with data without any failures as and when required
ensures that if a group of nodes fails the distributed system still continues to operate correctly
Graph by Hamzeh Khazaei
Consistency is achieved over time, as a result of validation from multiple nodes. This process of validation is called a Consensus algorithm
Consensus is a process of agreement between distrusting nodes on a final state of data
Imran Bashir
The Byzantine Generals Problem is a situation where involved parties must agree in order to avoid failure, but where some of the involved parties are corrupt and disseminating false information
This algorithm works on the idea that for a node that has enough stake in the system, any malicious attempt would outweigh the benefits of performing an attack on the system
Proof of Stake (PoS) is a category of consensus algorithms for public blockchains that depend on a validator's economic stake in the network
Image By https://blockgeeks.com/
Public key cryptography
Graph by Imran Bashir
Graph by Imran Bashir
By Ethereum Foundation [CC BY 3.0 (https://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
Ethereum is an open-source, public, blockchain-based distributed computing platform and operating system featuring smart contract (scripting) functionality
Wikipedia
Ethereum was initially described in a white paper by Vitalik Buterin, a programmer involved with Bitcoin Magazine, in late 2013 with a goal of building decentralized applications. Buterin had argued that Bitcoin needed a scripting language for application development. Failing to gain agreement, he proposed the development of a new platform with a more general scripting language
Wikipedia
In 2016 a decentralised autonomous organisation called The DAO, a set of smart contracts developed on the platform, raised a record US$150 million in a crowd-sale to fund the project. The DAO was exploited in June when US$50 million in ether were claimed by an anonymous entity.
Wikipedia
The event sparked a debate in the crypto-community about whether Ethereum should perform a contentious "hard fork" to reappropriate the affected funds. As a result of the dispute, the network split in two. Ethereum continued on the forked blockchain, while Ethereum Classic continued on the original blockchain
Wikipedia
Externally owned accounts
Contract accounts
contract ERC20Interface {
function totalSupply() public constant returns (uint);
function balanceOf(address tokenOwner) public constant returns (uint balance);
function allowance(address tokenOwner, address spender) public constant returns (uint remaining);
function transfer(address to, uint tokens) public returns (bool success);
function approve(address spender, uint tokens) public returns (bool success);
function transferFrom(address from, address to, uint tokens) public returns (bool success);
event Transfer(address indexed from, address indexed to, uint tokens);
event Approval(address indexed tokenOwner, address indexed spender, uint tokens);
}By Ethereum Foundation [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
By Francesco Strazzullo
