Traditionally, banks have maintained separate databases and exchanged messages to reconcile their records. Blockchain technology offers a different form of recordkeeping: a shared ledger whose approved entries are synchronized across authorized participants and protected by cryptographic controls. It offers banking a new way to organize trust among institutions that need to share records but do not want to surrender all control to one participant. The central question is not whether blockchain will replace banks, but how banks and public authorities can use distributed systems without weakening the trust on which money depends. Banks are turning to blockchain for speed, transparency, and cost savings. The blockchain revolution in the banking sector promises secure transactions, lower costs, and faster settlements. It reshapes everything from cross-border payments to compliance. This paper explains how banks are using blockchain technology today.