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Satoshi

Unlike the physical versions of global currencies, such as the British pound or U.S. dollar, cryptocurrencies predominately exist in the digital world. Despite this difference, a cryptocurrency can be divided into smaller units, just as the pound is broken into pence and the dollar into cents. In the case of bitcoins, the smallest unit available is called the satoshi.

The satoshi unit is named after Satoshi Nakamoto, published a paper in 2008 that jumpstarted the development of the bitcoin cryptocurrency. The paper, “Bitcoin: A Peer-to-Peer Electronic Cash System”, described the use of a peer-to-peer network as a solution to the problem of double-spending. The problem – that a digital currency or token can used in more than one transaction – is not found in physical currencies, as a physical bill or coin can, by its nature, only exist in one place at a single time. Since a digital currency does not exist in the physical space, using it in a transaction does not remove it from someone’s possession.

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RobertBarrow / bitcoin-pizza.md
Last active March 12, 2018 12:55
Bitcoin Pizza, Bitcoin Pizza Index, Bitcoin Pizza Day and Bitcoin Lightning Pizza

Bitcoin Pizza

On 22nd May 2010, programmer Laszlo Hanyecz made the first documented purchase of goods using bitcoin when he exchanged 10,000BTC for two pizzas supplied by Jeremy Sturdivant (which he had bought from Papa John's). Back then - when the technology was just over a year old - that equated to roughly $25 per pizza.

Here is a link to the original "Pizza for bitcoins?" post on bitcointalk.org.

Here is a link to the transaction on the Bitcoin blockchain.

Bitcoin Pizza Index

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RobertBarrow / merkel-tree.md
Last active March 12, 2018 12:11
Merkel Tree

Merkel Tree

The Merkle tree, also known as a binary hash tree, is a data structure that is used to store hashes of the individual data in large datasets in a way to make the verification of the dataset efficient. It is an anti-tamper mechanism to ensure that the large dataset has not been changed. The word 'tree' is used to refer to a branching data structure in computer science, as seen in the image below.

Merkel Tree

According to Andreas M. Antonopoulos, in the Bitcoin protocol:

"Merkle trees are used to summarize all the transactions in a block, producing an overall digital fingerprint of the entire set of transactions, providing a very efficient process to verify whether a transaction is included in a block."

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RobertBarrow / blockchain-vs-dlt.md
Last active March 12, 2018 11:47
Blockchain Technology vs Distributed Ledger Technology

What is the difference between distributed ledger technology and blockchain technology?

Quote: "The Difference between DLT and Blockchains" by Brian Behlendorf of the "HyperLedger" project (by "The Linux Foundation")

Okay... there actually... I mean, so, the difference between the term distributed ledger and the term blockchain has gotten pretty muddy out there in the broader world.

For me, personally, distributed ledgers are a great, very specific way to talk about this new kind of decentralized database, right, this system, so that you, and I, and everyone else out there, have a copy of a series of transactions that is kept absolutely in sync.

The specific term for that data structure used to be called blockchain, but now, everybody seems to be applying the term blockchain to anything on the spectrum, from cryptocurrencies to enterprise deployments of DLTs. >

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RobertBarrow / concensus-algorithms-vs-smart-contracts.md
Last active March 12, 2018 12:12
Blockchain - Consensus Algorithms vs Smart Contracts

Blockchain - Consensus Algorithms vs Smart Contracts

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RobertBarrow / permissioned-vs-permissionless.md
Last active March 12, 2018 11:23
Blockchain - Permissioned vs Permissionless

Blockchain - Permissioned vs Permissionless

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RobertBarrow / distributed-ledger-technologies.md
Last active March 12, 2018 11:52
Blockchain - Distributed Ledger Technologies (DLT)

Blockchain - Distributed Ledger Technologies (DLT)

Looking back to the last half century of computer technologies and architectures, one may observe a trend of fluctuation between the centralization and subsequent decentralization of computing power, storage, infrastructure, protocols, and code.

Mainframe computers are largely centralized. They typically house all computing power, memory, data storage, and code. Access to mainframes is mainly by 'dumb terminals', which only take inputs and outputs, and do not store or process data.

With the advent of personal computers and private networks, similar computational capabilities were now housed both on the clients, as well as the servers. This, in part, gave rise to the 'client-server' architecture, which supported the development of relational database systems. Massive data sets, which are housed on mainframes, could move onto a distributed architecture. This data could replicate from server to server, and subsets of the data could be accessed and processed

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RobertBarrow / wfp-building-blocks.md
Created March 9, 2018 10:04
World Food Programme - Building Blocks (Innovation Accelerator)

Building Blocks

WFP is taking first steps to harness blockchain technology to enhance our ability to provide effective, efficient assistance to the people we serve – and save millions of dollars.

Underpinning WFP’s Building Blocks project is blockchain, a cutting-edge technology that could transform the way in which humanitarian agencies deliver aid. Blockchain is a digital ledger technology used as a trusted way to track the ownership of assets without the need for a central authority, which could speed up transactions while lowering the chance of fraud or data mismanagement. Crucially, its peer-to-peer nature removes the need for verification from costly intermediaries such as banks or other institutions.

About

As a means of addressing the challenge of providing food assistance to over 80 million hungry people worldwide, WFP is taking early steps to harness blockchain technology to be able to deliver assistance more effectively. Building Blocks aims to make WFP’s growing cash-based transfer operati

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RobertBarrow / the-linux-foundation.md
Last active March 8, 2018 20:18
The Linux Foundation

The Linux Foundation

[The Linux Foundation][] partners with the world's leading developers and companies to solve the hardest technology problems and accelerate open technology development and commercial adoption. [The Linux Foundation][] makes it its mission to provide experience and expertise to any initiative working to solve complex problems through open source collaboration, providing the tools to scale open source projects: security best practices, governance, operations and ecosystem development, training and certification, licensing, and promotion.

Linux is the world's largest and most pervasive open source software project in history. [The Linux Foundation][] is home to Linux creator Linus Torvalds and lead maintainer Greg Kroah-Hartman, and provides a neutral home where Linux kernel development can be protected and accelerated for years to come. The success of Linux has catalyzed growth in the open source community, demonstrating the commercial efficacy of open source and inspiring countless new

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RobertBarrow / amply.md
Last active March 12, 2018 11:23
Project Amply strives to revolutionize early childhood development in Africa.

Project Amply strives to revolutionize early childhood development in Africa. Combining mobile and blockchain technology to increase impact and accountability of public services and generate real-time data.

Amply is a digital identity protocol that builds trust. We provide every child with their own self-sovereign digital identity based on the blockchain. This will enable children to receive benefits and services that they might have previously been excluded from.

In our pilot project, Amply is being used to replace an existing paper-based system to register children for a government funded pre-school subsidy in South Africa. Service providers use a mobile app to verify children’s attendance at classes and to capture other useful information. This will increase trust in the funding mechanism and make funding available to more children who need it. It will save administration time and costs. And it will provide really useful information about how and where services are being