Question-26: What are the two main purpose of “achieving consensus”?

Answer: Using the “achieving consensus” process miners/users running nodes are powering the network and accomplishes following two purposes

• Block Discovery: This is to agree on which miner gets the right to add a block of transactions.
• Validation of the transactions: To agree that the transactions included in the new block are legitimate.

Question-27: Which all are the approaches mostly used of achieving consensus?

Answer: Either of the following approach is used

• Proof-of-work
• Proof-of-stake

Question-28: Which cryptography is used to prove the validity of transaction?

Answer: It uses the Public/Private key cryptography to validate the bitcoin transaction.

Question-29: What is the use of Private key in transaction validation?

Answer: Private keys remain private and never-ever shared. Private key in Bitcoin would is used for the signing a digital transaction, which is the way the owner of the Bitcoin address proves on the network that he is the right owner of that address. Hence, private keys are used to authorize a transaction.

Question-30: What is the use of public key?

Answer: First point to note is public keys are public and those are visible to everybody. In Bitcoin world you can assume this is an email address. Hence, public keys in Bitcoin world are used for generating Bitcoin address. And you can share this publicly like your email address. If you want to receive a Bitcoin, you can share your address generated using public key. (Like send me email on my email id).