PicoCTF 2018 Walkthrough – General Warmups

General Warmup 1

Category : General

Points: 50

Problem

If I told you your grade was 0x41 in hexadecimal, what would it be in ASCII?

Hint

Submit your answer in our competition’s flag format. For example, if your answer was ‘hello’, you would submit ‘picoCTF{hello}’ as the flag.

Solution

The question is pretty straightforward that you are given a number in Hexadecimal and you have to find its corresponding ASCII value.

A Hexadecimal number is a number whose base is 16 i.e instead of 0-9 numbers like in decimal system (whose base is 10), a hexadecimal or hex number has 16 numbers before using the combination of the basic numbers. To incorporate additional numbers it has A to F along with 0 to 9 numbers like in decimal. To learn more about them you can go here.

Coming to the solution of the problem in hand we first find the decimal equivalent of the hex number. There are many such converters on the internet. One such can be found here.

After the conversion of 0x41 in decimal, we will be getting 65. Now we just need to find the ASCII equivalent of 65. ASCII stands for American Standard Code for Information Interchange which is nothing but the code given to letters, digits and special characters so that they can be easily mapped to computer’s binary form. You can read more about ASCII here.

Like Hex to decimal converters, there are many decimals to ASCII converters which you can check out. You can also refer the table below for some common ASCII codes. From the table, it’s clear that 65 maps to “A”. Hence the answer.

Just enter the same in the text field provided and hit submit.

Solution Flag

picoCTF{A}

General Warmup 2

Category : General

Points: 50

Problem

Can you convert the number 27 (base 10) to binary (base 2)?

Hint

Submit your answer in our competition’s flag format. For example, if your answer was ‘11111’, you would submit ‘picoCTF{11111}’ as the flag.

Solution

The question is pretty straightforward that you are given a number in decimal and you have to find its corresponding binary value.

A binary number is a number whose base is 2 that is it has only 2 numbers 0 and 1 and using only them all the other numbers are produced. The computer understands the binary format and all the instructions to the computer is given in binary at a low level or it is converted to it inside the computer. You can understand binary as two opposite values 0 & 1, low or high, on or off, true or false and so forth. You can read more about the binary numbers here.

Convert using any binary to decimal converter like the one here.

Enter the same in the text field provided and hit submit.

Solution Flag

picoCTF{11011}

General Warmup 3

Category : General

Points: 50

Problem

What is 0x3D (base 16) in decimal (base 10).

Hint

Submit your answer in our competition’s flag format. For example, if your answer was ’22’, you would submit ‘picoCTF{22}’ as the flag.

Solution

The question is pretty straightforward that you are given a number in hexadecimal and you have to find its corresponding decimal value.

You can learn about both hexadecimal and decimal values from General Warmup 1’s solution and you can use the online converter here.

Conversion of 0x3D gives 61 after conversion. Enter the same in the text field provided and hit submit.

Solution Flag

picoCTF{61}

For more capture the flag challenges visit CTF. 

If you want to see Leetcode explained solutions visit Leetcode Solutions.

Check out my socials below in the footer. Feel free to ask any doubts in comment section or contact me via Contact page I will surely respond. 

Happy Learning 🙂