Just Cryptography

Learn Cryptography and Information Security

  • 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 […]

  • How Cryptography is applied to Off-Chain Assets

    Contributed by Michael Shuufeni. In this article, you will learn what are off-chain assets and how cryptography is applied to them. What are Off-Chain Assets? The current architecture of the blockchain has four layers. 1- the hardware layer is concerned with distributed trusted hardware 2-Layer 0 is concerned with the network of the blockchains. 3- […]

  • Extended Euclidean Algorithm and its applications in cryptography

    The Extended Euclidean Algorithm has several applications. In this post, I’ll show you a python implementation as well as some of its applications. It is used to calculate the greatest common divisor (GCD) of two numbers and also calculates two numbers x and y such that ax + by = gcd(a,b). In this post, I’ll […]

  • Applications of cryptography in network security

    In this post, I’ll show you some applications of cryptography in network security. Current cryptographic algorithms are hard to understand, some of them use complex mathematics as their basic building blocks. Sometimes, this fact makes it difficult for us to see how we can apply these algorithms to provide security in a network. So, let’s […]

  • What is Secure Shell (SSH) and how does it work?

    Secure Shell (SSH) is a network protocol used to securely communicate in an unsecured network. SSH is the protocol that most people choose to use for remote login and tunneling. There are many client applications available in different operating systems, such as: PuTTY for windows. Bitvise  SSH client for windows. OpenSSH for windows. PuTTY for […]

  • How to implement the Vigenère cipher in python

    Another substitution cipher is the Vigenère cipher. In this post, I give you an explanation of the cipher and a python implementation. The Vigenère cipher is categorized under polyalphabetic substitution ciphers. This type of cipher works as follows[1]: They use related monoalphabetic substitution rules. The key is used to determine what rule to apply for […]

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