​This blog is a two-part series on blockchain, a game-changing distributed ledger technology (DLT). Part 1 is an overview of the specifics of blockchain, including a description and example of its implementation. The focus is on the blockchain technology underlying bitcoin. Part 2, to be included in a blog next week, focuses on smart contracts and a description of the plethora of innovations and opportunities enabled by blockchain technology in diverse fields of endeavor. 
 
Blockchain technology is a game-changing, disruptive, distributed ledger technology (DLT) that has the potential to accelerate creativity and catalyze innovation. It can reform and transform the delivery of public and private services in many fields of endeavor, including financial, legal, supply-chain, consumer, business-to-business and others. 
 
WHAT IS A BLOCKCHAIN? 
 
Marmelab defines blockchain as: 
 
"A ledger of facts, replicated across several computers assembled in a peer-to-peer network. Facts can be anything from monetary transactions to content signature. Members of the network are anonymous individuals called nodes. All communication inside the network takes advantage of cryptography to securely identify the sender and the receiver. When a node wants to add a fact to the ledger, a consensus forms in the network to determine where this fact should appear in the ledger; this consensus is called a block." 
 
A blockchain DLT promotes the collaborative creation of digital distributed ledgers with properties and capabilities exceeding paper-based ledgers. It is a new technology-focused method for storing, recording and transferring digital assets.  A blockchain’s distributed ledger asset database can be shared across a global network of multiple sites, geographies and institutions. All participants, or nodes, within the network have their own identical copy of the ledger. Its entry can be updated by one, some or all parties in the network according to rules agreed by all parties, which forms a consensus. Any changes in the ledger is reflected within each node's copy within minutes or seconds, which enhances productivity and efficiency. The accuracy of the information stored in the ledger is maintained using cryptography. This is to facilitate security and a new kind of trust among a group of non-trusted peers, without the existence of a central authority.
 
There are several key components of a blockchain, including a peer-to-peer network, distributed data storage, computational engines (with memory) and cryptography.  The network is a collection of globally distributed nodes, with associated computational engines and storage. The nodes are used to execute the cryptographic algorithms needed for reaching a consensus, based upon the established rules. The storage contains the distributed ledger or blockchain information.
 
See this infographic on blockchain technology.
 
 
HOW IS A BLOCKCHAIN USED AND IMPLEMENTED?
 
Consider the example of a modern credit card processing transaction. There are several processing steps from the consumer, merchant, processor and banks. Each step may encounter fees, which collectively may be significant. Now imagine a similar consumer-merchant process with no middle men (e.g., merchant, processor). This then becomes person to person, or peer-to-peer. It is desirable in such circumstances to facilitate a level of trust among peers, who may not know or trust each other, and reach a consensus. This is feasible with modern cryptography.  As a result, a blockchain enables non-trusted peer-to-peer transaction processing with minimal fees and maximum efficiencies.
 
Implementing a peer-to-peer network can be complex. For example, consider the double spend problem. Sarah has $25 which she sends to two (2) individuals; Jerry ($25) and Stephon ($25); however, Sarah only has $25. Who gets the $25? Each potential transaction (e.g., Sarah sending $25 to Jerry and Sarah sending $25 to Stephon) is considered a fact that must be ordered using a methodology that has been agreed to by all global parties or peers. While the two facts are sent out at roughly the same time, they may arrive at their destinations at different times. The first to arrive at the destination, according to the globally agreed to order, gets the $25.
 
Blockchains are used as the foundational technology for cryptocurrency, as well as other trusted applications. PwC defines cryptocurrency as:
 
"a medium of exchange, such as the US dollar, but is digital and uses encryption techniques to control the creation of monetary units and to verify the transfer of funds"
 
Several blockchains exist today, many for cryptocurrencies such as bitcoin (the most popular) and ether. Blocks are a method of ordering facts in a network of non-trusted peers. Nodes, which are associated with peers, compete or mine to create the next official block in the chain. These competing nodes, denoted miners, submit their own local block in the competition. (This is synonymous to competitors rolling dice to see who gets the double six, except there are a substantially large number of competitors and the act of "rolling the dice" is each miner executing a complex cryptographic algorithm). A local block contains a collection of facts that are pending. Once a specific miner wins the competition, then it's local block becomes the next official block in the chain, and the pending facts within the block are confirmed.
 
The process of globally distributed miners reaching consensus on the next block may result in some conflicts. In such cases, reconciliation or resolution of the conflicts is required. This requires consensus. The blockchain network for bitcoin uses the hashcash proof-of-work (PoW) consensus algorithm to achieve distributed consensus.
 
The bitcoin blockchain uses the double Secure Hash Algorithm (SHA) 256. It creates a 256-bit (32 byte) hash (also called a digest or signature) of the facts, a hash of the previous block's header, and a random number. It executes two iterations of the SHA-256 algorithm. The hash is almost unique, and it is highly unlikely that any two individuals will generate the winning hash.
​
The winning miner's local block becomes the next block, and is added to the permanent chain of blocks to form or extend the blockchain. In addition, the winning miner gets a fixed amount of cryptocurrency as a reward. (Hence the term miners, as they are mining for cryptocurrency). The miners then repeat this process to find the next block in the chain.
 
See this infographic on bitcoin mining.
 
One pays to store facts in a blockchain. Reading facts are free, one just needs to run their own node. (Some nodes are used to simply store the blockchain ledger, while others are used to mine). Adding facts to a block costs a small fee. Mining a block brings in the money of all the fees of the facts included in the block, plus the reward if the miner wins the competition. All payments are made in the actual cryptocurrency; therefore, a blockchain generates its own money.  A 12.5 bitcoin (BTC) reward is granted to the winner for bitcoin, while a 5 ether (ETH) reward is given for the Ethereum network.
 
OTHER BLOCKCHAIN TECHNOLOGIES
 
The blockchain network for bitcoin is one of several. Notable others include Ethereum and Hyperledger, open source platforms sponsored by the Ethereum Foundation and Linux Foundation, respectively.
 
Several blockchain consensus protocols exist, in addition to PoW. The most notable is the Proof-of-Stake (PoS) algorithm, which operates with a finite amount of cryptocurrency created at inception. With PoS, the winner of the next official block in the chain is determined by the fraction of coins one owns in the network. Several validators or stakeholders (as opposed to miners) compete and the validator with the largest amount of cryptocurrency wins.  The Ethereum network, which currently uses PoW, plans to move to PoS in 2018.


​Please see the crowdfunding campaign on iFundWomen.com to develop geeRemit, a global remittance global app based upon blockchain technology.

​Many people in developing countries have difficulty making ends meet. They rely on family members and friends in the west to send money home. Remittance solutions are a vital component of the financial infrastructure and an important source of income for millions of families in the world’s 140 developing countries.  The World Bank has projected global remittances to reach $444B this year (see Figure), a 3.3% increase versus 2016.
 
Furthermore, in sub-Saharan Africa (SSA) and other developing countries, more citizens own mobile devices than bank accounts. The number of unique subscribers is expected to reach 520M by 2020. Mobile is driving innovation and digital and financial inclusion in SSA. For example, mPesa is a popular mobile money solution that is the major source of payments in Kenya. Leveraging such devices in this space is a $16B opportunity. Bringing mobile payments and global remittance together in a cost-effective and secure manner creates a multi-billion dollar opportunity in SSA and hundreds of developing countries worldwide.
 
Global remittance funds are used by recipients for health care, education, proper nutrition and other critical expenses. However, the typical international money transfer requires significant communication between the sender and receiver. One or both need to calculate exchange rates, synchronize amounts, collect personal details and then ensure the cash has been sent and received. In addition, the cost for sending money home can be expensive. For example, in 2016 the average global cost of sending $200 was 7.45% (or $14.90). SSA had the highest cost at 9.8% or ($19.60). Therefore, global remittance comes with high transfer and other fees, concerns about security and issues for the sender and receiver just getting to the money transfer facility.
 
The traditional remittance solution to developing countries is to leverage the services of Western Union, Moneygram or Ria.  However, their services offer the highest fees. Recent partnerships, e.g., Viber and Western Union or WeChat and Western Union, enable mobile apps to play a larger role in this space. While this addresses one side of the logistical issue of reaching an establishment to initiate the money transfer, it does not address this issue for the recipient. Furthermore, money transfer fees are still high.
 
There are existing blockchain-based alternatives to traditional money transfer methods; e.g., Sentbe, SCI and Paybill. While these options provide some reduction in fees and increased security, they do not address the logistical issues around getting the funds to the recipient. Furthermore, the recipient does not have immediate access to the funds.
 
geeRemit is a mobile global remittance app that offers reduced cost, world-class security based on a game-changing blockchain technology, and mobile-to-mobile transactions. The initial geeRemit market focus is SSA; a $34B opportunity in a $444B global remittance market (see Figure). This is because SSA, particularly East Africa, is a place where mobile money is an integral part of every-day society. Also, this app offers the consumer an opportunity for the most significant reduction in transaction fees.
 
In summary, geeRemit offers a low-cost, logistics-free global remittance service. It is based upon blockchain, an exciting, new, secure game-changing technology. A mobile phone is used to send funds home, and the recipient receives it as mobile money directly on their phones. It resolves all location-based logistical issues, as the transactions are done via mobile phones. The money is available in a short time frame, offering the fastest, most economical and convenient service on the market. This is an attractive value proposition for customers. See this geeRemit video for more information.

​I waited with great anticipation to see the movie, Hidden Figures. I was so inspired when I saw it. I learned that many of my experiences were also those of these three fabulous women. The way young Katherine Johnson explained the mathematical equations in one of the opening scenes felt right at home. FORTRAN was the first programming language I learned, and I ran them on a massive IBM computer. I left the movie excited, inspired, and also knowing that their story is my story.
 
However, I did not expect the sense of connection and history I experienced when I read the book. That’s when I learned the story of Dr. Christine Darden, the fourth woman profiled in the book. She worked as a supersonic aircraft designer at NASA. It turns out that I used some of her groundbreaking work in computational fluid dynamics (CFD) in my Ph.D. thesis research. It was then that I knew I stood on her shoulders and we have a historical connection. I immediately felt as though I had to meet her and began to look for ways to make this happen.
 
Several weeks later I learned that Dr. Darden was coming to the area for “STEM Resilience:  Dinner and Conversation with Dr. Christine Darden”, an event at a local restaurant. I was so excited and immediately purchased a ticket. I reached out to the host, asking her to allow me to spend just a few minutes with Dr. Darden one-on-one. Well, she actually had me sit next to her for the evening. We spent 90 minutes together, getting to know each other, sharing our experiences, and conversing and sharing words of wisdom with three young ladies at the table with us.
 
Dr. Darden is a very warm, soft-spoken and affable individual. She is also wise as a serpent, but soft as a dove. We talked about her professional experiences as well as her beloved family. (She knew quite a bit about my background, as someone had shared my vita with her before she arrived). I was very interested in her NASA career, including how she navigated and overcame her challenging environment to make her impact. She was very competent in her work and asked the right questions at the right time. For example, when she noticed that her male colleagues who started at NASA with similar credentials began to advance, she asked her manager about her advancement. When she did not get an acceptable answer, she went straight to the director and asked him. His response was that no one had ever asked him that question. Within a few weeks, she was promoted to engineer, from her position as a human computer. Dr. Darden mentioned to us that she only learned that the women in the NASA diversity office championed her cause by reading the book. She did not know prior to that.
 
I asked her how she developed her work on CFD algorithms.  It turns out her boss more or less left her along to think and work, and that’s how she was able to do her work. In fact, she was the sole author on a paper describing her groundbreaking work. She spoke very fondly of her boss, and stayed in contact him for many years after he retired.
 
We also compared notes about our time in graduate school. Our experiences were similar. When she walked into a classroom, she was the only woman and her classmates were all Caucasian men. My classes were primarily Caucasian and Asian men and maybe two or three women, including me. The difference was that her classmates were willing to work with her, to be part of working groups. For me, no one but the foreign students would work with me. Of course they turned out to be the smartest students in class so I was always in good groups.
 
I told her about my experiences where students and faculty said unpleasant things to me, such as “I believe you’re in the wrong place” or “I don’t think you’re going to make it here, but we’ll take your fellowship money”. She was appalled at this and asked me how I coped. I told her that I knew the truth, and they would eventually learn the truth. I did belong there and I eventually made believers out of them! She mentioned that for some, that would have been a discouragement. Not so with me.  What is enlightening to me is she did not have such experiences in school.
 
I thoroughly enjoyed my time with Dr. Darden, getting to know her, learning about her career and her family. I will always cherish the personal time I had with her!
 
I was very thankful to the host of the evening, Dr. Christine Grant. She is one of the first African-American women to earn a Ph.D. in Chemical Engineering, and a professor and associate Dean at North Carolina State University. I suggested that the three of us take pictures at this event, for this is history. I’ve included this picture with the three or us, along with one I took with Dr. Darden.