Yesterday I was reading about Blockchain, its architecture and other technical detail. I being from ABAP background thought of coding a basic blockchain in ABAP. Please note that intent here is to build a basic blockchain so that its understanding can be increased. Implementation of the blockchain may differ based on the requirements but basic concept remains the same.
The other features such as power of distributed data management and sync, validation of blocks etc. is out of scope of this blog.
Blockchain Basics
As the name suggests Blockchain is basically chain or collection of blocks. Typically a block comprises of a header which has different fields, a hash (cryptic value) of previous block and Transactions Data in hashed form (we will dig into this in our next blog). The first block in the blockchain is known as genesis block. N number of transactions together make a block. These all block are distributed over the network as local copy on each connected node.
Once the maximum number of transactions in a block is reached, the three parts of the block which are header, data(detail of transactions) & previous block hash are combined and hashed(encrypted ) with a key known as proof of work or nonce. The correct key or proof of work is determined based on the difficulty level. For example we say a generated hash is valid only and only if it contains 5 leading zero’s. So this leading 5 zero’s is known as the difficulty level.
The process of determining the right key consumes the major time and is known as mining. Depending on which currency it is, rewards are given accordingly to the one who finds a valid Proof of Work. The moment someone finds a valid proof of work all the connected nodes are informed and if 50% of the nodes agreed then this new hash is added as a new block to the chain.
What we are planning to build
* A basic prototype of Blockchain, where a report will take input as difficulty level and number of blocks to be generated and then output will be hash and nonce for value for each hash. In the current blog our focus is to highlight how it works. In next blog we will focus on how the transactions are arranged in a block:)
ABAP Implementation of basic Blockchain
* Created a basic report with below mentioned selection screen parameter
* A Type for basic blockchain structure
* Genesis block
* First step is to add genesis block, we are using SHA1 algorithm for encryption.
* Determine Next Block Hash
* An iterative loop to repeat number of blocked needed – 1 since genesis block is already added.
* Inside block loop have another loop to concatenate current and previous hash data along with Nonce value and generate a hash. Validate the hash as per difficulty if valid exit and append the block
* Output Display
What is expected next?
* Deep dive into Block transactions arrangement – Merkel tree
* Implementing Blockchain using BOPF – This will be more like learning BOPF by implementing a blockchain using it
* Adding flavor of CDS to Blockchains with annotations:)
* Finally if time permits a HCP UI5 app to display and run this chain rather than traditional report
Feel free to provide your feedback,open to all ears:). Lets share and learn. http://bit.ly/2G3nm5H #SAP #SAPCloud #AI
