Blockchain

Seminar Topic on Blockchain

 A blockchain originally block chain is a growing list of records, called blocks, which are linked using cryptography.Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a merkle tree root hash).

A Brief History of Blockchain

To start, let’s talk about the history of the blockchain. Before it was ever used in cryptocurrency, it had humble beginnings as a concept in computer science — particularly, in the domains of cryptography and data structures.

The very primitive form of the blockchain was the hash tree, also known as a Merkle tree. This data structure was patented by Ralph Merkle in 1979, and functioned by verifying and handling data between computer systems. In a peer-to-peer network of computers, validating data was important to make sure nothing was altered or changed during transfer. It also helped to ensure that false data was not sent. In essence, it is used to maintain and prove the integrity of data being shared

In 1991, the Merkle tree was used to create a “secured chain of blocks” — a series of data records, each connected to the one before it. The newest record in this chain would contain the history of the entire chain. And thus, the blockchain was created.

In 2008, Satoshi Nakamato conceptualized the distributed blockchain. It would contain a secure history of data exchanges, utilize a peer-to-peer network to time stamp and verify each exchange, and could be managed autonomously without a central authority. This became the backbone of Bitcoin. And thus, the blockchain we know today was born, as well as the world of cryptocurrencies.

How does the blockchain work?

Any data put into the blockchain must be verified. Transactions are grouped together in blocks, hence the name blockchain, then verified by the computers (nodes) in the network. When a computer joins the network as a node, they receive a copy of the blockchain which acts as proof of all the transactions that have been performed.

This means that all data stored on the network is transparent; it is public by default. This also means that all the data in the blockchain network cannot be corrupted or deleted.

However, this doesn’t mean you can see who is doing the transaction. For instance, with bitcoin, the public can see that someone is sending an amount to someone else but there is no information linking the transaction to anyone. This is because the public keys linking the transaction are kept anonymous.

As well, it is un-hackable because it doesn’t have a centralised system. Instead, it is hosted by millions of nodes around the world, instead of being in one central place.

Source

https://en.wikipedia.org/wiki/Blockchain
https://www.investinblockchain.com/what-is-blockchain-technology/
https://www.standard.co.uk/tech/what-is-blockchain-explainer-uses-importance-a3779746.html

Ethical Hacking on Hacktivism

Hacktivism

What is Hacktivism

Hacktivism is the act of hacking a website or computer network in an effort to convey a social or political message. The person who carries out the act of hacktivism is known as a hacktivist.

In contrast to a malicious hacker who hacks a computer with the intent to steal private information or cause other harm, hacktivists engage in similar forms of disruptive activities to highlight political or social causes. For the hacktivist, hacktivism is an Internet-enabled strategy to exercise civil disobedience. Acts of hacktivism may include website defacement, denial-of-service attacks (DoS), redirects, website parodies, information theft, virtual sabotage and virtual sit-ins.

 A Brief History of Hacktivism

1996—The word “hacktivism” is coined by Omega, a member of the hacking group Cult of the Dead Cow (cDc).

1998—Electronic Disturbance Theater, a group of online political performance artists, hack the Pentagon, the Mexican government, and the German stock exchange to protest the clampdown on the Zapatista Army of National Liberation.

2001—A branch of cDc, Hacktivisimo, announces the hacktivist community’s dedication to combat “state-sponsored censorship of the internet” in the Hacktivisimo Declaration.

2003—Fifteen-year-old Christopher Poole uses a computer in his bedroom to create 4chan.org, the eventual birthplace of the notorious hacktivist group Anonymous.

2011—Hacktivist group LulzSec’s releases private information from Senate.gov just to show it can.

2011— Servers at the NSA, the Pentagon, NASA, the Department of Defense, and other military departments are infiltrated. A hacker called sl1nk claims credit and releases formerly secured information as proof.

2012— Anonymous claims credit for infiltrating and taking down the CIA website.

2014— In what the FBI and Secret Service said was “among the most sophisticated attacks ever launched against US government systems,” someone hacks the White House computer system. The FBI begins publishing numbers of hacktivism incidents in its annual reports.

2016— Information leaked from Democratic National Committee emails conspiring against potential presidential candidate Bernie Sanders are published on WikiLeaks.

Acts of hacktivism, or "hacktions," tend to fall into one or more of the following categories:

Distributed Denial of Service (DDoS) Attacks: Attacks which bring down websites or otherwise disrupt Internet activity by systematically sending so many requests to a server that it cannot handle the traffic and is rendered temporarily useless. Common examples include email bombing and web sit-ins.

Website Defacements: Attacks which change the content of websites, usually for the purpose of spreading a political message.

Internet Worms: Programs designed to spread themselves within a network, either for the purpose of disrupting activity or spreading a message. 

Source: CyberSecurityDegrees.com

Sources:

https://www.highspeedinternet.com/resources/political-hacking-in-the-us/

https://www.techopedia.com/definition/2410/hacktivism

https://foreignpolicy.com/2013/04/29/hacktivism-a-short-history/ 

https://cs.stanford.edu/people/eroberts/cs201/projects/2010-11/Hacktivism/hacktivism.html#