ChangeCipherSpectilaisuus

ChangeCipherSpec is a message within the Transport Layer Security (TLS) protocol. It is sent by the client to the server after the initial handshake and before the client finishes sending application data. The primary purpose of the ChangeCipherSpec message is to signal that the subsequent messages will be encrypted using the newly negotiated cipher suite and keys.

The TLS handshake process involves several steps, including the exchange of cryptographic parameters, authentication, and key agreement. Once these steps are successfully completed, both the client and the server have established a shared secret key and agreed upon a specific encryption algorithm and hashing method. The ChangeCipherSpec message serves as a confirmation that both parties are ready to transition from unencrypted communication to encrypted communication.

Upon receiving the ChangeCipherSpec message from the client, the server acknowledges it and also sends its own ChangeCipherSpec message. This ensures that both endpoints are synchronized in their understanding of the impending switch to encrypted traffic. After exchanging these messages, all subsequent application data exchanged between the client and server is encrypted according to the negotiated security parameters, providing confidentiality and integrity to the communication session.