esab64

Date: 13, March, 2021

Author: Dhilip Sanjay S

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Question

Was it a car or a cat I saw?

• mxWYntnZiVjMxEjY0kDOhZWZ4cjYxIGZwQmY2ATMxEzNlFjNl13X

Solution

• As you can guess the name says base64 in reverse. So, it must be something related to base64.

• So, initially I base64 decoded the given string. But it was gibberish:

cat esab64 | base64 -d
����ىX��H��@΅�����ā��	����L͔X͗]�

• May be it had something to do with reversing. So, I reversed the string and then base64 decoded it. It gave a string, in which the flag was in reverse.

• On reversing the obtained decoded string, I was able to get the flag.

from base64 import b64decode

string = 'mxWYntnZiVjMxEjY0kDOhZWZ4cjYxIGZwQmY2ATMxEzNlFjNl13X'
rev_string = string[::-1]

decoded_string = b64decode(rev_string)
print("Before reversing the decoded string:" , decoded_string, sep="\n")
print("After reversing: ", decoded_string[::-1], sep="\n")

• Output:

Before reversing the decoded string:
b'_}e61e711106bd0db1b78efa894b1125bf{galf'
After reversing: 
b'flag{fb5211b498afe87b1bd0db601117e16e}_'

Solution

flag{fb5211b498afe87b1bd0db601117e16e}