Blockchain (Polish for chain of blocks) has recently been a popular word in the Internet’s clouds. In this article I will try to expose what the famous Blockchain is and what it can do be useful.

Data structures

First of all, you need to explain what data structures are in order to understand what is blockchain. Data structures are in general a way of organization, management and storage of data in computer memory. More precisely, the data structure is a set of data values, relations between them and functions or operations that can be used for data. Different data structures serve different purposes such as relational databases, which use tree-B indexes for downloading data and certain implementations compilers use Hash Table to find identifiers. Data structures include:

• Record, also known as a structure or a short cut (for example, a point with X, Y coordinates)
• The board
• List (one way or two way)
• Object
• Tree
• Mixing table
• Graph

and many, many more different variants of these data structures.

Blockchain

Blockchain is a data structure. Specifically, it is a kind of one-way list containing strongly interconnected blocks using cryptography. Each block contains the hash of the previous block, time stamp and transaction data. The exception is the so-called Genesis Block (pol. block (initial). This is the first block forming a chain of links with other blocks. The assumption the block chain is resistant to data modification and easy verification that the data is not have been forged. Modification of any block, results in the generation of completely different hashes for subsequent blocks, which allows for easy verification that the data has not been forged.

And for what it’s for who?

Nowadays, the use of blockchain is all about handling various transactions like for example:

• Stocks
• Currencies
• Trade

The main use of this data structure can be seen in cryptovalutters such as Bitcoin. In the following articles I will try to implement a sample chain of blocks.