For this challenge, we are given an Imgur link to a jpg image, gate.jpg, and are asked to evaluate some function.
The hint states that we need to find 101 image 110 and that the flag format is riftCTF{eval}.
Those who have studied Discrete Mathematics, Boolean Algebra, or worked with Logic Gates will recognize this as the truth table for the exclusive disjunction logical operator (aka xor or ⊕).
For those who do not recognize the table, the challenge is still solvable as one can recognize that based on the inputs x and y, there will be some sort of output z.
Result: Using the xor operator or the truth table, we can evaluate 101⊕110 to get 011.
Flag: riftCTF{011}