How the security/confidentiality process on Bitcoin Blockchain is ensured?
1) A bitcoin block includes all records of transactions publicly and transparently. Anyone checking over blocks can track movements of BTC's amongst several accounts.
2) It is so easy to trace BTCs sold/bought amongst addresses. On the other hand, the person who sends/receive BTC is confidential.
3) Transfers take place in an encrypted way. There is no information about the user's identity on blocks.
4) Everyone can easily see any your BTC address, but no one can know that it is ‘your’ BTC address unless you say so.