Just Cryptography

Learn Cryptography and Information Security

  • What ports are secure in your computer?

    In information security, we consider secure ports those that encrypt the communication, or all the data that passes through them. But, you need to be aware that this does not mean that they cannot be successfully attacked by a hacker. There are many different security attacks that can be carried out even if the communication…

  • What are insecure ports in your computer?

    Informally, insecure ports are ports that do not encrypt the communication that occurs through that port. Ports in a computer are a virtual place where network connections start and end. The ports are virtual as they are software created and managed by your operating system. This means you can configure them from your operating system.…

  • What is phishing in cybersecurity?

    Phishing attacks are one of the most common cybersecurity attacks. The attack is meant to steal information by deceiving users. It is carried out by sending emails with links for the target to click on them. The links will take the target to a webpage where it will be asked for personal information. It can…

  • One-Time Pad cipher in Python

    The One-Time Pad cipher was proposed by Joseph Mauborgne. In this post, I’ll show you a Python implementation of this cipher. This cipher is the same as the Vernam cipher. The only difference is that every key is used only once. So, we need to generate a random key every time we encrypt a new…

  • Vernam cipher in Python

    Vernam cipher was introduced by Gilbert Vernam in 1918. In this post, I’ll explain the algorithm and show the implementation in Python. Vernam cipher is the ultimate defense against the cryptanalysis used to break the Vigenère cipher. The mentioned attack relies on the fact that the key and the plain text share the same frequency…

  • The 7 tenets of zero trust (NIST SP 800-207)

    The 7 tenets of zero trust provided in NIST SP 800-207, are an attempt to define what should be included in a zero trust architecture instead of what should be excluded. Several authors define zero trust in terms of what should be excluded, like perimeters. But these attempts, go back to the use of perimeters…

  • What is an NFT

    Contributed by Ismael Stephanus. NFTs are digital assets that live on a blockchain. They are non-interchangeable with other items because they have unique properties and no two NFTs are the same. NFTs are used to represent ownership of unique items and allow for tokenizing of things like art collectibles, they are mainly secured by the…

  • What is a next generation firewall (NGFW)?

    A next generation firewall is a must-have in nowadays cybersecurity environments. NGFWs improve traditional firewalls in many ways, to improve network security. According to Gardner, “Next-generation firewalls (NGFWs) are deep-packet inspection firewalls that move beyond port/protocol inspection and blocking to add application-level inspection, intrusion prevention, and bringing intelligence from outside the firewall”. So, let’s start…

  • What is Zero Trust Architecture?

    Zero trust architecture (ZTA) provides us with tools and principles to increase security in enterprise networks. This effort becomes especially relevant nowadays with the increase in cybersecurity threats and attacks. A zero trust architecture assumes that an attacker is always present in the network and therefore, access to every resource is denied by default until…

  • Architecting secure Cross-Chain infrastructure with CCIP

    Contributed by Mulanduleni Niilungu. Combining different blockchain networks is of great interest because it can be used to give new and enhanced services by communicating several blockchain networks. For that purpose, we can use CCIP to securely create services that use more than one blockchain network. Introduction Blockchain networks rely on their own communities and…

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