Question-16: What is hash function?

Answer: Sometime hash function also referred as hash only. This a computation, where you provide any text string, how long does not matter as an output it would generate fixed length output. As example below

hash(“HadoopExam”) = “awewjnvfvrjerb3434pvbkf044 vcq]sw]rr+dsdgsglfdkgnfdgsefrst43353535=-”

hash(“QTechie”)   =        “+zwerwerknfg[]2434543gfvmdajvaerwetkresklsdg’0-=-gjn9252nsdvdsrtu94”

Length of the output would always remain same, does not matter how big your input. To create final hash output, it requires the algorithm. Most popular one as of now is SHA1 and SHA2. Hash is a backbone for cryptocurrency. Sometime this is also known as hashing or signature.

Question-17: In case of bitcoin, how transactions are tracked?

Answer: In case of blockchain or bitcoin transactions are tracked using chain of hashes or signature. And all hashes are organized by blocks of time in chronological order.  And using this technique there is no need of single entity to track of transactions.

Quiestion-18: Now can you explain blockchain once again?

Answer: A blockchain is made up of multiple blocks of transactions, and these blocks are connected with each through hashes or signature. There are both kind of public and private blockchain exists.

Question-19: What is a ledger?

Answer: In the payment world a ledger is a constantly changing document. Every time someone wants to send a transaction, a new row of data is added to the ledger. In case of bitcoin around every 10 minutes a new block of transactions is added what can be defined as ledger.

Question-20: What all are the attributes for the block in a Bitcoin?

Answer: Following are the blocks in case of bitcoin

• Block Hash: This is a unique identifier for the block. Whatever the data is in the block, it creates a hash value and represented using 256 bits. The data can be entire balance sheet. In the world of Bitcoin, it does not contain the hash of the same or itself rather it has the hash or signature from previous block. And that’s the reason a chain is created. Hash is created using header of the block.
• Coinbase Transactions: New blocks are mined over the network and this represent a first transaction of each block mined on the network. And it adds a new Bitcoin to the supply, which is given as a reward to the miner who adds the block to the chain.
• Block Height Number: This is a number which represent how many blocks are there between first block and current block.
• Merkle Root: This is a hash that allows proof of validity of the blockchain.