bitcoin cryptocurrency There are two main ways the block chain ledger can be corrupted to steal bitcoins: by fraudulently adding to or modifying it. The bitcoin system protects the blockchain against both using a combination of digital signatures and cryptographic hashes. hashsalim@gmail.com

1. An introduction to bitcoin,
the blockchain, andcryptocurrency
HASHIM SALIM

2. About Me (HASHIM SALIM)
 Received first crypto token in 2016 when a friend sent me Dogecoin
 - Got into Bitcoin in 2017
 - Part of wazirxwarrior (crypo educator)
 - Holding Token(btc,xrp,sxp,eth,dot,troy,wrx,matic,)
 - Blockchain resists change
 - Mining
 Complect electronic and communication engineering
 Software tester
 Broadband technician
 Full time cryptotrader

3. The Story About Currency
Examine a story what the world looked like before money was invented. It's a story built on
the idea of Barter.

4.  From then on, banks became the intermediary or the middlemen of transactions. And to control the
demand and supply of currency and to standardize trade, the government stepped in. The freedom
of decentralization offered to the people by metal coins was somehow giving way to a more
centralized concept of fiat currency through government-regulated financial institutions. This paper-
printed currency has no intrinsic value of its own, whereas governments/central authorities give it an
attributed value by declaring it as a legal tender in respective territories.
 The power that was previously controlled by wealthy individuals became institutionalized in the form
of banks and governments. People believed that these centralized bodies provided protection as well
as a reliable trust system for trade and the flow of information. But still, the system had its taboo of
negatives.
 There existed scenarios when the banks or the central body suddenly collapsed. Discrepancies arose
when they charged huge fees in exchange for keeping gold in their vault. Though the central
authority seems to lessen the complexities in trade, it possessed several other threats which we have
seen in history, like inflation and banks printing more currency.

5. FIAT VS CYRPTOCURRENCY
Fiat (USD, Euro, GBP) Cryptocurrency (Bitcoin, Ethereum, IOTA)
• Controlled by banks and governments
• Created by governments
• Inflationary
• Infinite supply
• Can be created at any time
• Open M – F, 9 to 5
• Controlled by the people that use it
• Created by solving math algorithms
(mined)
• Deflationary.
• Finite supply
• Set amount released every year
• Open 24/7/365

7. History:
Bitcoin was first mentioned in a 2008 research paper published under the name Satoshi
Nakamoto.
Some mainstream websites began accepting bitcoins 2013.WordPress started in
November 2012 followed by OKCupid in April 2013, Atomic Mall in November 2013,
TigerDirect in January 2014, and Overstock.com that same month.
In October 2013, Chinese internet giant Baidu had allowed clients of website security
services to pay with bitcoins. During November 2013, the China-based bitcoin exchange
BTC China overtook the Japan-based Mt. Gox and the Europe-based Bitstamp to become
the largest bitcoin trading exchange by trade volume.
The first bitcoin ATM was installed in October 2013 in Vancouver,
British Columbia, Canada.

8. Bitcoin is like email
16UwLL9Risc3QfPqBUvKofHmBQ7wMtjvM 31uEbMgunupShBVTewXjtqbBv5MndwfXhb
INTERNET
Hash…@gmail.com Rose….@gmail.com

9. WHAT IS IT?
• Bitcoin – a peer-to-peer electronic cash System
The payments in the system are recorded in a public ledger
using its own unit of account, which is also called bitcoin.
• Deflationary
• Finite amount
• Cryptocurrency – a virtual currency that
uses encryption to prevent “double
spending”
• Blockchain – a decentralized, trustless
ledger (list of transactions), on which only
additions can be made
• The ledger history can never be change
• All computers on the blockchain have the
ledger

10. HOW IT BEGAN
• Satoshi Nakamoto
• Bitcoin’s anonymous creator
• Believed to be a pseudonym
• Published bitcoin’s whitepaper in 2009
• Financial collapse of 2008
• Poor fiscal management by banks, investment
firms, and government
• The world had a need to get away from the
central authority of money
BLOCKCHAIN EXPLAINED (The Yap Tribe)
• All tribespeople know and keep track of every
transaction within their village
• They all know who owns what and how much
• Any time a transaction is made all the people in
the tribe are gathered and are told of the
transaction
• Subsequently, they all “update” the database in
their head of who owns what

11. Abstract:
Bitcoin is a peer-to-peer payment system introduced as open source software in 2009 by developer Satoshi
Nakamoto.
The payments in the system are recorded in a public ledger using its own unit of account, which is also called
bitcoin.
The bitcoin system has no central repository and no single administrator, which has led the US Treasury to call
bitcoin a decentralized virtual currency.
Although its status as a currency is disputed, media reports often refer to bitcoin as a crypto currency or digital
currency
Bitcoins are created as a reward for payment processing work in which users offer their computing power to
verify and record payments into the public ledger. Called mining, individuals or companies engage in this activity
in exchange for transaction fees and newly created bitcoins.
Besides mining, bitcoins can be obtained in exchange for fiat money, products, and services.
Users can send and receive bitcoins electronically for an optional transaction fee using wallet software on a
personal computer, mobile device, or a web application.

12. HOW BLOCKCHAIN WORK

13. WHAT IS BLOCKCHAIN?
Decentralization - Need of the hour
With a centralized authority in place, better coordination is achieved. Centralization comes with its own
shortcomings. The biggest downside is the abuse of power.
In such cases, decentralization has great significance. The concept of decentralized networks laid the foundation
for the evolution of Bitcoin blockchain. Decentralized networks aren't controlled by a single authority or a single
node. Each node in the network share processing power and decision making processes. The nodes are
independent and are distributed across the globe.
Distributed Ledgers
Ledger is a record of transactions. In normal cases, the ledger will be in the hands of authority. In the
concept of distributed ledger, the same copy of the ledger will be distributed among a group of participants.
The blockchain can be called a ledger that shares and synchronize information concurrently among all
network participants. Therefore every record (usually transactions) in the ledger is seen by everybody and
every change made to the ledger is reflected across all participants in the network. Thus blockchain can be
called a distributed ledger. The group of technologies that follows the concept of distributed ledger among
the participants is called Distributed Ledger Technologies or DLTs in short. There comes a variety of DLTs,
where blockchain is one of them.

14. let'scompare it with a
notebook. A blockchain is
like a notebook where
pages are blocks. The pages
in a notebook carry the
data similar to how the
block carries the data in
blockchain. You see the
data in those pages are
always connected or linked
to one another . Similarly in
the blockchain, blocks are
connected or linked to each
other.
To get an idea about how blockchain is a ledger,
In a classroom, a student
seeks the help of his
classmate if he misses out
any information say a few
pages of notes.similarly, in
the blockchain, if a node
fails, the other participating
nodes overcome the
deficiency via helping the
crashed nodes to sync up
with the rest of the network.

15. A Basic Dictionary of Blockchain
Here is a quick read to the common terms related to blockchain. However, we'll see them in detail in the coming
chapters. But for now, this glossary will help you grasp a general idea about the blockchain terms used commonly.
Peer to Peer Network
Blockchain is a peer to peer network. In a peer to peer (P2P) network, every computer can share data with each
other. Each participant in the network has equal power and is commonly called a "node". These types of networks
don't require any centralized storage facilities or server coordination and hence are majorly used in distributed
systems.
Node
In its simple sense, a node is a machine in a blockchain network. A group of nodes connected together forms a
blockchain network. A node can be a mining device, a storage device, or any other device which plays different
kinds of role in different blockchain networks. Nodes are responsible for storing a copy of the transactions that are
happening in the network. When a new node connects to a blockchain network, it downloads the entire copy of
the blockchain to date and synchronizes with the network until it has the latest block held by all the nodes in the
peer to peer network. Every time a new block is created, a copy of it is added to every node in the network. All
miners in the blockchain network are nodes, however, all nodes are not miners.

16. Miners
Specific nodes in the blockchain network that are responsible for the verification and validation of transactions
blocks. They play an important role in maintaining and extending the blockchain by adding new blocks to the
In a public blockchain they are responsible for creating new currencies, hence the name miner.
Transaction
A transaction in blockchain can be defined as the smallest unit of a task in a blockchain network. Successful
transactions that are agreed upon by the nodes in the network will become candidates for creating a block.
Block
Blockchain is a ledger, where transactions are recorded. The successful transactions are recorded inside a block.
other words, a block represents a data structure for storing successful transactions along with metadata (block
number, timestamp, etc.) and the blocks are linked together to form a blockchain.
Blockchain
A cryptographically linked sequence of blocks in a chronological order spanning across the nodes forms the
blockchain. Blockchain is like an ever-growing book (ledger) with blocks forming the pages of it, in a sequential
fashion and every node in the network having the exact same copy of the book. The network keeps on growing
long as new blocks get added to the network.

17. What does a Blockchain look like?
we saw blockchain is a ledger. A ledger records transactions. In a blockchain, these transactions are recorded
inside the block. These blocks are linked together to form a chain of blocks - blockchain.
Pic1;simp blockchain
Pic2 ;exact block
Timestamp: The time at which the block was created.
Nonce: This is a random number. But the significance of this will be discussed
later when we talk about Proof of Work and Mining. For now, let's think of it as
a random number.
Root Hash: This is the combined hash of all the transactions included in the
block, obtained by creating a Merkle tree of transaction hashes. Well, don't
worry if you aren't familiar with these terms. We'll go in detail about hashes and
Merkle trees in the coming section.
Previous Hash: The hash value of the previous block's header. This is an
important concept, which makes blocks a chain. More about it later.
Note: The first block in a blockchain is termed as the Genesis Block. This is the block that is created during the inception of the chain.

18. Hash: Fingerprint for Data
To simplify, hashing is a method in cryptography that converts any form of data into a unique string of text. The
algorithm used for conversion is called the hashing algorithm. The fixed-size output from a hashing algorithm is called
the hash.
Features of Hashing Algorithm
One-way: While it is easy to calculate the hash of data, it isn't possible to decode the original data from a hash. Like
our example with the juice blender, we can make juice out of the fruit but not the reverse.
Deterministic: A hashing algorithm always produces the same output for the same set of input.
Fast Computation: The hash function should be able to compute the hash value without taking a considerable
amount of time.
Avalanche Effect: Any small change in the input data would produce an unpredictably different hash as output.
Withstand Collisions: Since the length of a hash is fixed, theoretically, there is a chance of collision (where two different inputs
producing the same hash for a given hashing algorithm). But it is very unlikely to happen. Also, a hash algorithm should withstand
artificial collisions.

19. WHERE DOES IT COME FROM?
• Mining (mining rigs) –
computer processors
connected to the blockchain
that validate transactions by
solving complex
cryptographic hashing
Algorithms
• Coins are given as rewards
to the machine/person that
solves the algorithm

20. BASIC PURPOSES
1. Confirms transactions
2. Adds block to blockchain
WHAT GIVES IT VALUE?
• It is worth what people will pay for it
• Supply and Demand
• What gives our dollars value?

21. IS IT SAFE?
• Blockchain is unhackable
Altering the ledger would require 51%
ownership/takeover of the network
• Personal
• Hashing and cryptography hide
password input
• Private keys are 64 characters long
• XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXXXXXXXXXXXXXXXXXXXXXXXXX
XXXXXX
• Danger still lies in 3rd party
exchanges holding your wallet
Typical Database Security = 1
central point for hackers to focus on
Blockchain Secutiry = millions of
points, hacker would have to
simultaneously hack everycomputer

22. HOW IT WILL CHANGE THE WORLD
• People are in control of their money
• Electronic trading of tangible assets
• real estate
• vehicles
• Instantly and extremely cheaply send money abroad
• Avg transaction fee (Ethereum) = $1.10
• Avg transaction fee (Western Union) = 9-10%
• Avg transaction fee (Visa) = 3%
• Give access of the global financial market to the nearly 2 billion people who
do not/cannot get bank accounts
• Prevent fraud
• Voting
• Banking

23. QUESTION ?