Symmetric Key Encryption

I was fortunate enough to work in the security industry while studying for the CISSP.  

Dealing with firewalls and creating VPNs was a daily routine, and this made the Cryptography domain of the CISSP VERY easy.  

Others may not have the same opportunity, so I thought I would share with everyone how symmetric encryption is used in real life. 

Let me know if you have any questions and thanks for watching! 


  • 9sorenson

    Thank you so much, please make more videos to help clarify complex topics

    • studynotesandtheory

      You’re welcome! And I will ! @9sorenson:disqus

  • Paramate Boonsook

    Thank you very much Study Notes and Theory. It helps bright up my comprehension about IPSEC, However, I am a bit confused between IPSEC and VPN. Correct me if I am wrong.
    IPSEC is to set up the secured communication channel between 2 points.
    – Tunnel Mode= between FW and FW
    – Transport Mode = between host and host
    AH provides integrity and non-repudiation
    ESP provide confidentiality
    IPSEC use MAC to mitigate the complexity of PKI.

    VPN is to extend your private network via using public WAN like internet.
    I used to adopt free OPENVPN. My admin create my certificate and send it to me. I just copy my certificate and then paste into correct folder. Later, I just click connect button to establish VPN. Nevertheless, I do not any concepts behind my VPN connection. Please clarify it for not only me but also other candidates.

    Moreover, VPN can appear in numerous form such as IPSEC VPN, MPLS VPN, and else. What difference among them? Or just creating VPN by various means? Thanks in advance.

    • studynotesandtheory

      You got it correct about it being the same VPN by different means. VPNs just means those RFC 1918 IP addresses within your organization, can commuicate with another company’s RFC 1918 addresses. IPSec I found can’t be explained by words, you have to SEE it in action. What you said about IPSec is correct above, however I feel like if I created a video demonstrating how it works, you would truly understand. Please allow me some time to create this video, and I’ll let you know!