The Unix epoch (or Unix time or POSIX time or Unix timestamp) is the number of seconds that have elapsed since January 1, 1970 (midnight GMT). This explains how date & time values are actually stored on computers: using an…
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Hashing Algorithms for Integrity Validation
Imagine working for the British Secret Services during World War 2 or during the cold war. As part of your role, you would be expected to exchange secret messages with your allies. Your messages would most likely be encrypted using…
Hashing Algorithms for Storing Sensitive Data
More and more online systems such as e-commerce websites, online banking apps, or social networks need to access some sensitive data about you including your password, your credit card details and more recently, some biometric data (e.g. for fingerprint authentication…
Hashing Algorithms for Memory Addressing
In this blog post, we will investigate the use of hashing algorithms to quickly locate a record in a large database. Let’s consider the database of members of a social network such as Instagram, Twitter or Facebook. Every time the…
Recursive vs. Iterative Palindrome Check
For this challenge we will investigate two algorithms used to find out if a word is a palindrome or not. The first algorithm will use an iterative approach, the second algorithm will use a recursive approach. Iterative Approach An iterative…
Blackbeard’s Hidden Treasures
The period of the late 17th and early 18th centuries is known as the Golden Age of Piracy. During this period the most notorious and the most feared of all pirates was Blackbeard. There are many legends based around Blackbeard’s…
Blackbeard’s Treasure Map
We have all heard of the famous English pirate called Blackbeard who sailed the seven seas during the XVIII century. Through his numerous acts of piracy, Blackbeard accumulated a huge collection of riches including golden coins, jewels, golden plates and…
The Pigpen Cipher
The Pigpen cipher (a.k.a. tic-tac-toe cipher) is a geometric substitution cipher, which exchanges letters for symbols which are fragments of a grid. Secret Message Using the key provided on the right, can you decode the following secret message? Pigpen…
The Rail Fence Cipher
The rail fence cipher (sometimes called zigzag cipher) is a transposition cipher that jumbles up the order of the letters of a message using a basic algorithm. The rail fence cipher works by writing your message on alternate lines across…
Semaphore Code Using Python Turtle
Flag semaphore is a telegraphy system conveying information at a distance by means of visual signals with hand-held flags. Information is encoded by the position of the flags. The current flag semaphore system uses two short poles with square flags,…
Flowchart Studio
Python Syntax