# What is Modular Arithmetic? Usually, when you want to perform division, you do something like: $$ \frac{3}{5} = 1,(6) \Rightarrow 1\frac{2}{3} $$ But there are some cases when you only need the remainder. $$ \frac{\text{Dividend}}{\text{Divisor}} = \text{Quotient} + \text{Remainder} $$ Where \\(\text{Quotient} = k \times \text{Divis
14 Aug
## Get Familiar with the Task I assume you've already read the description and noticed that the flag in this challenge resembles a familiar Base64 encoding. However, after decoding it, you see what looks like a series of random bits: ``` QФ~ĦZòÕöï!﨧.§ä>îÓF7Oþ²ëY+æèZs¶ ·¨2 [MQìüF ¬ ``` This time, the flag was truly enc
20 Aug
## The Discrete Logarithm Problem Now that you understand modular arithmetic, we can move on to its applications. In the previous post, we discussed how to perform modular computations. Now, it's time to learn how these computations are used in cryptography. Calculating the remainder in an equation like this might be easy: $$ 5^{13}\bmod{17} =
21 Aug