BTC_Token | Token system based on bitcoin system | Blockchain library

FairAccess system is an identity management and access control Framework for IOT using the Bitcoin Blockchain. FairAccess laverages the blockchain as a resilient database or, a policy retrieval point, where all encrypted access control policies for each resource are stored in form of transactions. It plays the role of a public witness that garantees the correct enforcement of pre-defined access control policies through the consensus mechanims. it serves also as logging databases that ensures auditing functions. Furthermore, it prevents forgery of token through transactions integrity checks and detects token reuse through the double spending detection mechanism This project helps users to define the control access policy and ditribute accesss tokens to the requesters. the Tokens are exchanged over cutsom bitcoin's transactions. Notice: To run the code you need to setup a local bitcoin node by installing bitcoin core. This project is a poc for a scientific paper. In this scenario, the system is a home webcam security system. It is built using a raspberry pi 2 board with its dedicated camera .The Raspberry pi is connected to an Ethernet LAN providing a remote access to this system. In this case, the camera represent the resource to control access to, in consequence the authorized clients, depending ontheir rights could perform multiple actions (video reording, live streaming, Time-Lapse Photography etc.). As a proof of concept, we will take a snapshot and save it on the raspberry pi SD card, define our control policy and give the clients a remote access using a token distribution over our local blockchain. Components: The raspberry pi 2 is a low coast, credit-card sized computer which includes quad-core ARM Cortex-A7 CPU and 1 GB of RAM. It’s capable of running many Linux distributions and recently Windows 10. The Raspberry Pi camera module can be used to take high-definition video. It has a five megapixel fixed-focus camera that supports 1080p30, 720p60 and VGA90 video modes, as well as stills capture. It attaches via a 15cm ribbon cable to the CSI port on the Raspberry Pi. The Raspberry Pi with its attached camera makes a good IOT system. Setting up the camera software. raspistill -v -o Token1.jpg The camera will take a picture within 5 second, save it to the file Token1.jpg. by giving the –V option we will get various informational messages. Setting up the Bitcoin node. And the wallet The bitcoin installation process could be found under this link : http://raspnode.com/diyBitcoin.html After a successful installation, we create the file bitcoin.conf and edit it, adding an rpc user and a password. bitcoin.conf should look something like this: rpcuser=myuser rpcpassword=21Hy2d5kycuoLzWxdJjQoVN1jtL7Q5kzqhHz3ZfuYNCU. Afterward we could run our bitcoin node using bitcoind –regtest to join the local blockchain. And the bitcoin client bitcoin-cli –regtest. The -regtest option helps us to get a self-contained testing environment: everything (the Peers included could be running on my machine). Due to the technical constraints of the IOT objects, in this scenario we use Lightweight wallets. This kind of wallets use a simplified payment verification (SPV) mode which only requires them to download part of the blockchain. For a testing environment, it’s safer and costless to use Bitcoin’s test network (testnet) or regression test mode (regtest). In this scenario we are using a Regtest, where everything (the Peers included could be running on the local machine or on our LAN). Program anatomy. Bitcoinj is a Java implementation of the Bitcoin protocol. This library provide us a wallet, and perform the required operation: send/receive transactions without needing a local copy of Bitcoin Core and has many other advanced features. Bitcoin is suitable for usage on constrained devices providing the SPV mode. A Getting started tutorial for Java, on how to use the library is available https://bitcoinj.github.io/getting-started. Our system aims to distribute access tokens across the bitcoin network inside financial transactions exchanged between the actors. These transactions flows between wallets, they are digitally signed for security reason and recorded after confirmation into the blockchain. Bitcoin uses a scripting system for transactions. In fact, inside the transaction a list of instructions are included to describe how the receiver could spend it, and therefore he can gain access to them and to its contents (in our case the access token). A transaction is valid if the script is excuted without error using the inputs provided by the receiver. This kind of distribution is benfical, the history of a transaction can be traced back to the point where the bitcoins were produced. In the rect of this article we will, continue using tokens instead of bitcoins. So our system will exchanges Tokens included on original bitcoins tx.