Secure webpages or SSL (Secure Sockets Layer) refer to the use of encryption and secure protocols to protect the confidentiality and integrity of data transmitted between a web server and a client. SSL has been succeeded by TLS (Transport Layer Security), but the term SSL is still commonly used to refer to the secure encryption of webpages.

When a webpage is secured with SSL, the URL typically begins with “https://” instead of “http://”. The “s” in “https” stands for secure, indicating that the webpage is using encryption to protect data.

Here are the key aspects of secure webpages and SSL/TLS:

1. Encryption: SSL/TLS uses encryption algorithms to encode the data transmitted between the web server and the client. This ensures that even if the data is intercepted during transmission, it remains unreadable and secure. Encryption prevents unauthorized access and protects sensitive information, such as login credentials, credit card details, or personal information.
2. Authentication: SSL/TLS provides authentication mechanisms to verify the identity of the web server and establish trust with the client. This is typically achieved through the use of SSL/TLS certificates issued by trusted certificate authorities (CAs). These certificates contain information about the website’s identity and are digitally signed to ensure their authenticity. Clients can validate the certificate presented by the server to ensure they are communicating with the intended and legitimate website.
3. Data Integrity: SSL/TLS also ensures data integrity, meaning that the data transmitted between the web server and the client remains intact and unaltered during transit. Integrity checks, such as message digests and digital signatures, are employed to detect any tampering or modification of data.
4. Secure Handshake: The SSL/TLS handshake process establishes a secure connection between the web server and the client. During the handshake, the client and server agree on encryption algorithms, exchange encryption keys, and verify each other’s identity using the SSL/TLS certificates. This secure handshake process sets up the foundation for encrypted communication.
5. Compatibility and Browser Support: SSL/TLS is supported by most modern web browsers and is widely used across the internet. Browsers display visual indicators, such as a padlock icon or a green address bar, to signify that a webpage is secure and encrypted with SSL/TLS.

SSL/TLS is crucial for protecting sensitive information, securing online transactions, and establishing trust between websites and their visitors. It is widely adopted to ensure the privacy and security of data transmitted over the internet.