Danni-Tech

Making the Complicated Simple

Security Plus PKI - INTRO SSL/TLS HANDSHAKE

  • Key Points from This Video on the SSL/TLS Handshake

    Introduction:

    • This video continues from the previous lesson on how PKI is used in SSL/TLS, focusing now on the client’s role and the SSL/TLS handshake process.
    • The SSL/TLS handshake is a process that establishes a secure connection between the client and server.

    The Client’s Role in the SSL/TLS Handshake:

    1. Initiating the Secure Connection:

      • The client (e.g., a web browser) has CA certificates pre-installed, allowing it to trust certificates issued by recognized Certificate Authorities.
      • Since the client has multiple trusted CAs installed, it doesn’t need to contact the CA directly for every server connection.

    2. OCSP Stapling (Before the Handshake):

      • The server has already obtained an up-to-date certificate status from the CA through OCSP stapling.
      • This allows the client to receive certificate status information directly from the server, reducing the need to check with the CA during the handshake.

    The SSL/TLS Handshake Process:

    1. Certificate Request:

      • The client initiates a request for the server’s certificate, starting the handshake process.

    2. Certificate Validation:

      • The client verifies the server’s certificate to ensure:
        • Ownership: The server truly owns the certificate.
        • Legitimacy: The certificate is valid and issued by a trusted CA.
      • This validation step helps the client confirm that it’s communicating with the legitimate server.

    3. Session Key Generation:

      • After the certificate is validated, the client and server generate session keys for:
        • Symmetric Encryption: Provides confidentiality, securing data during transmission.
        • Message Authentication Code (MAC) Key: Ensures data integrity and authentication, confirming that data has not been altered in transit.

    4. Establishing Secure Communication:

      • The session keys create a secure tunnel for data exchange between the client and server.
      • This marks the completion of the SSL/TLS handshake, allowing for secure, encrypted communication.

    Key Takeaways for the Security+ Exam:

    1. The client uses pre-installed CA certificates to trust servers without contacting the CA directly.
    2. OCSP stapling reduces the need for real-time certificate status checks by the client.
    3. The SSL/TLS handshake involves verifying the server’s certificate for both ownership and legitimacy.
    4. Session keys are generated during the handshake to secure data through symmetric encryption.
    5. A MAC key is also created to ensure data integrity and authentication.
    6. The handshake establishes a secure tunnel for encrypted communication between the client and server.