Using an example in the business or finance industry, describe how the following
cryptographic protocols work:
A. Secure sockets layer (SSL).
Secure Sockets Layer (SSL) is a cryptographic protocol commonly used in the business and finance industry to ensure secure communication over the internet. Let's take the example of online banking to understand how SSL works.
When a user accesses their bank's website to perform online banking, SSL helps establish a secure connection between the user's browser and the bank's server. Here's how it works:
1. Handshake: The user's browser (the client) initiates a connection request to the bank's server. The server responds by sending its SSL certificate, which contains a public key, to the client. This certificate is digitally signed by a trusted Certificate Authority (CA).
2. Certificate verification: The client's browser checks the validity of the SSL certificate by verifying its digital signature and confirming the authenticity of the CA. If the verification is successful, it ensures that the server belongs to the bank and establishes trust.
3. Session key exchange: To establish a secure and encrypted communication channel, the client and server generate a symmetric session key using asymmetric encryption algorithms like RSA. The public key from the server's certificate encrypts the session key, which can only be decrypted by the server's private key.
4. Encryption: With the session key now securely exchanged, the client and server transition to symmetric encryption. All data transmitted between the client and server is encrypted using the shared session key, providing confidentiality. As a result, any information intercepted during transmission remains unreadable to unauthorized individuals.
5. Data transfer: During the session, the client's browser and the server exchange encrypted data, such as account information, transactions, and login credentials. This data is securely transmitted over the internet and decrypted at the receiving end.
6. Session termination: Once the communication is complete, the SSL session can be terminated. The shared session key is discarded, ensuring that subsequent sessions use new and independent keys for security.
Overall, SSL ensures secure transmission and protection of sensitive data in online banking and other business transactions. It combines asymmetric encryption for securely exchanging session keys and symmetric encryption for efficient data transfer, allowing both confidentiality and integrity in the communication channels.