SSL/TLS (Secure Sockets Layer/Transport Layer Security) is a cryptographic protocol used to provide secure communication between a web browser and a web server, ensuring the integrity and confidentiality of data in transit. Here are some key aspects of SSL/TLS:

1. _Encryption_: SSL/TLS encrypts data to prevent eavesdropping and interception.

2. _Authentication_: SSL/TLS verifies the identity of the server and client, ensuring that data is sent to the intended recipient.

3. _Key Exchange_: SSL/TLS establishes a secure key exchange between the client and server, enabling encrypted communication.

4. _Certificate-Based_: SSL/TLS uses digital certificates to verify identities and establish trust.

5. _Secure Connection_: SSL/TLS creates a secure connection between the client and server, indicated by "https" and a lock icon in the browser.

SSL/TLS is used to secure:

1. Web browsing (HTTPS)

2. Email communication (SMTPS)

3. Virtual private networks (VPNs)

4. Web services (APIs)

5. Blockchain networks (secure node communication)

In blockchain networks, SSL/TLS is used for:

1. Secure node-to-node communication

2. Protecting sensitive data (e.g., private keys, transaction data)

3. Authenticating node identities

4. Ensuring confidentiality and integrity of data in transit

5. Complying with security and regulatory requirements

SSL/TLS is an essential protocol for securing online communication and protecting against eavesdropping, tampering, and man-in-the-middle attacks.