Blockchain is a distributed database on which bitcoin transactions are stored.
Bitcoin is a virtual currency.
Each transaction data is encrypted & stored as a block on every computer on the distributed network. Then when next transaction is done another block is created and stored on each computer.
Blockchain eliminates the need of a central authority & a central institution for e.g. Bank.
It is fault tolerant i.e. even if one computer goes offline, there is no loss of data as it is available on other computers within distributed network which can be 1000s in number.
It is a public ledger. It uses public key and private key combination to register a block which holds the transaction.
Every block is identified using a unique hash value (alphanumeric combination up to 256 bits) & this block also stores the hash value of previous block. In case there is any change done to the block, the hash value of the block changes & makes the block invalid & hence no data can be tampered.
This technique is being extended beyond bitcoins & being explored by banks and governments to store transactions, property records, votes etc.
1. Always data availability
2. No scope of data tampering
3. No scope to steal the information (unless password is stolen).