repetitions

Author: Theoneste Byagutangaza | 100 points

Description

Can you make sense of this file?

Download the file here.

Solution

Once we download the file and cat it, we get the following text.

$cat enc_flag 
VmpGU1EyRXlUWGxTYmxKVVYwZFNWbGxyV21GV1JteDBUb
FpPYWxKdFVsaFpWVlUxWVZaS1ZWWnVhRmRXZWtab1dWWm
tSMk5yTlZWWApiVVpUVm10d1VWZFdVa2RpYlZaWFZtNVd
VZ3BpU0VKeldWUkNkMlZXVlhoWGJYQk9VbFJXU0ZkcVRu
TldaM0JZVWpGS2VWWkdaSGRXCk1sWnpWV3hhVm1KRk5XO
VVWVkpEVGxaYVdFMVhSbFZrTTBKVVZXcE9VazFXV2toT1
dHUllDbUY2UWpSWk1GWlhWa2RHZEdWRlZsaGkKYlRrelZ
ERldUMkpzUWxWTlJYTkxDZz09Cg==

From this we can tell that it's Base64 from the '==' at the end of the string. From here we can drop it in CyberChef and use the Base64 formula to get the flag.

Once we drop it in CyberChef and use the Base64 forumla to convert it, we can see it doesn't work the first time. Taking the hint of the title 'repetitions', we use the Base 64 forumla six times to finally get the flag.

Flag

The flag we get in CyberChef is picoCTF{base64_n3st3d_dic0d!n8_d0wnl04d3d_492767d2}