Page 54 - CITS - Computer Software Application -TT

COMPUTER SOFTWARE APPLICATION - CITS

Phase 1: During this initial phase, both the client and the server send “hello” packets to each other. These packets
contain essential information such as the IP session details, chosen cipher suite, and protocol version. This
exchange is crucial for setting up the foundation of security.

Phase 2: In the second phase, the server takes the lead by transmitting its certificate and its key exchange
information. The server’s role in this phase concludes with the dispatch of a “Server-hello-end” packet, marking
the end of its contribution.

Phase 3: The third phase involves the client’s response to the server. The client forwards its certificate and key
exchange details to the server during this stage.
Phase 4: The final phase encompasses the execution of the “Change Cipher Suite” procedure. This pivotal
step signifies the transition to an encrypted communication state. Following this phase, the Handshake Protocol
concludes, paving the way for secure data transmission.

Change-cipher Protocol
The Change Cipher Spec Protocol is closely integrated with the SSL record protocol and plays a crucial role in
the SSL/TLS connection setup. Until the Handshake Protocol concludes, the SSL record output remains in a
“pending” state. Once the Handshake Protocol is successfully completed, this “pending” state transitions into the
“current” state.
The Change Cipher Spec Protocol is simple in nature, consisting of a single message that is just one byte in
length. This message can have only one possible value. The primary purpose of this protocol is to trigger the
transfer of the data in the “pending” state to become the new “current” state.
In essence, the Change Cipher Spec Protocol serves as a catalyst for moving the SSL/TLS connection from the
negotiation phase (Handshake Protocol) to the encrypted data exchange phase (current state), ensuring that the
encryption settings agreed upon during the handshake are applied to subsequent communication.
Alert Protocol
The Alert Protocol is an integral part of the SSL/TLS protocol suite, designed to enhance the reliability and
communication between a client and a server.
This protocol is responsible for transmitting alert messages between the two parties, conveying crucial information
about the status and health of the SSL/TLS connection.

Alert messages generated by the Alert Protocol can encompass a range of situations, including errors, warnings,
or notifications. These messages play a vital role in ensuring that both parties are informed about any anomalies
that might arise during the course of the communication.
Alert messages serve various purposes, such as signaling issues related to the SSL/TLS connection’s security,
such as certificate problems or unexpected closures. They also assist in diagnosing and troubleshooting any
potential problems that might arise during the communication process.
By employing the Alert Protocol, SSL/TLS connections become more robust and responsive, as both parties are
promptly made aware of any potential issues that might impact the integrity, confidentiality, or authenticity of the
exchanged data. This ultimately contributes to a safer and more secure communication environment.

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CITS : IT&ITES - Computer Software Application - Lesson 01-17