Challenge Description
Aha, a challenge dealing with bases! We have this string, with no other clue about how it has been encoded:
bDNhcm5fdGgzX3IwcDM1
For my past CTF challenges, it is quite a common occurrence for flags to be Base64 encoded. Let’s test the hypothesis.
For encoding and decoding tasks, my go-to tool is CyberChef, since it can analyse the string and recommend a decoding method as well. This functionality is useful for many challenges, including this one.
Decoding
After entering the string as input, CyberChef actually recommended decoding the string from Base64, which meant that the string was indeed Base64 encoded. Doing this gave me the following output:
l3arn_th3_r0p35
PicoCTF Hint: Submit your answer in our flag format. For example, if your answer was 'hello', you would submit 'picoCTF{hello}' as the flag.
We just have to wrap the decoded string with
pico{}to get the flag.
Flag
picoCTF{l3arn_th3_r0p35}