Blockchain Technology
Joshua Ervin

Abstract—This survey paper describes the value of blockchain technology.  It will layout the protocols and security methods utilized by blockchain and how future implementation could be beneficial to people and companies world wide.  There is a lot of buzz circulating around this technology and many companies have already developed their own proprietary blockchains.  It will be very interesting to see how this technology will revolutionize the way business is done on the internet in the coming years.
I.	INTRODUCTION
In recent years cryptocurrencies such as Bitcoin and Ethereum have been gaining rapid attention as well as price increases.  The idea of having a decentralized currency with global reach is very appealing.  But how does it work? The answer is the blockchain. This survey paper will explain the technology and security that make up the blockchain.  Blockchain can be defined as a type of distributed ledger that is made up of blocks which store cryptographically hashed and its data reliant upon the previous block in the chain[1].

II.	Networking & Security
Blockchain is a P2P network using the IP protocol consisting of nodes that hold a full and accurate replication of a database that contains the history of every ledger as well as ownership information[2].  Since there is no central node all of the nodes on the network utilize as well as provide resources equally.  In order to receive blocks nodes must first connect with any other valid node using a specified port over TCP.  Nodes work with a consensus service that provide instructions on how to proceed with blockchain updates after every transaction.
	Since blockchain operates over a P2P network there is no single point of failure which effectively eliminates the risk of a DDoS attack disrupting operation[2].  In a case where a node is disrupted there are still numerous nodes within the network that can provide the information needed.  Every node contains a complete copy of the ledger.  Although resilient blockchain still faces threats such as global internet outages, transaction malleability, exploits on block creation and validations, etc.… 
III.	Concerns 
With the rising popularity of blockchain technology many companies are looking to adopt blockchain given the numerous benefits but there are still draw backs to this system.  One issue facing the adoption of blockchain into a business is scalability.  In order to connect and interact with the blockchain is to first download and install the appropriate software which can be quite time consuming given that every set of existing blockchains must be first downloaded and validated.  There are also migration issues with existing data that needs to be transferred into a form that the blockchain can recognize.
Other issues include Government involvement and regulations.  Once blockchain technology is recognized as a standard there is concern that the adoption process being slowed down by government regulation.  Introduction of new laws and regulations may arise in order to keep the industry compliant[3].

IV.	The Future
The future of blockchain being adopted by businesses and other institutions as a primary ledger system is imminent.  Many companies have already adopted this technology and created their own proprietary blockchain.  One company that is pushing the adoption of blockchain technology is IBM.  They provide an open-source blockchain solution specifically built for enterprise[4].  The healthcare industry is also looking towards adopting blockchain technology as it will improve data sharing, a higher level of security and integrity, reduce wait times, minimize drug counterfeiting, and reduce human error[4].  
V.	Conclusion
Blockchain technology although currently known mainly for providing the backbone for cryptocurrency transactions has many other applications that will revolutionize the way companies and institutions conduct business.  The decentralized P2P network architecture provides security, reliability, and resilience.  The time and monetary cost to adopt blockchain in industry is worth the investment in the long run.  Applications for a blockchain infrastructure are seemingly limitless and only increasing. 

References
[1] “Blockchain Explained - Distributed Ledgers and Blockchain Technology,” Blockchain Technologies. [Online]. Available: http://www.blockchaintechnologies.com/blockchain-definition. [Accessed: 01-Dec-2017].

[2] A. vamsital, “The Architecture of Blockchain..(4/5),” Vamsi Talks Tech, 21-Oct-2016. [Online]. Available: http://www.vamsitalkstech.com/?p=1615. [Accessed: 01-Dec-2017].

[3] “IBM Blockchain basics: Introduction to distributed ledgers,” IBM - United States, 21-Aug-2017. [Online]. Available: https://www.ibm.com/developerworks/cloud/library/cl-blockchain-basics-intro-bluemix-trs/index.html. [Accessed: 01-Dec-2017].

[4] “Blockchain in healthcare: Patient benefits and more,” Blockchain Unleashed: IBM Blockchain Blog, 03-Nov-2017. [Online]. Available: https://www.ibm.com/blogs/blockchain/2017/10/blockchain-in-healthcare-patient-benefits-and-more/. [Accessed: 01-Dec-2017].