Challenge: BeepBoop Cryptography
Help! My IOT device has gone sentient! All I wanted to know was the meaning of 42! It’s also waving its arms up and down, and I… oh no! It’s free! AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA Automated Challenge Instructions Detected failure in challenge upload. Original author terminated. Please see attached file BeepBoop for your flag… human.
BeepBoop
beep beep beep beep boop beep boop beep beep boop boop beep beep boop boop beep beep boop boop beep boop beep beep beep beep boop boop beep beep beep beep boop beep boop boop boop boop beep boop boop beep boop boop boop beep beep boop beep beep boop boop beep boop beep boop boop beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep boop boop beep beep boop beep boop beep boop boop boop boop beep boop beep beep boop boop boop beep boop boop beep beep boop boop beep beep beep beep boop beep boop boop beep boop boop boop beep beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep beep boop beep boop boop beep boop beep boop boop boop beep beep boop beep beep boop boop beep boop beep boop boop beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep boop boop beep beep boop beep boop beep boop boop boop boop beep boop beep beep boop boop boop beep boop boop beep beep boop boop beep beep beep beep boop beep boop boop beep boop boop boop beep beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep beep boop beep boop boop beep boop beep boop boop boop beep beep boop beep beep boop boop beep boop beep boop boop beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep boop boop beep beep boop beep boop beep boop boop boop boop beep boop beep beep boop boop boop beep boop boop beep beep boop boop beep beep beep beep boop beep boop boop beep boop boop boop beep beep boop boop beep beep boop boop boop beep boop boop boop beep beep boop beep beep boop boop boop boop boop beep boop
Intro
The hint is given indirectly in the challenge: waving hands up & down
This means it is communicating in binary form: 0 & 1
Solve
1. Replace beep with 0
sed -i 's/beep/0/g' BeepBoop
2. Replace boop with 1
sed -i 's/boop/1/g' BeepBoop
3. Remove spaces
cat BeepBoop | tr -d ' ' | tee cat BeepBoop
4. Output
0000101001100110011010000110000101111011011100100110101101100111011100100110010101111010011101100110000101101110011001110111001000101101011100100110101101100111011100100110010101111010011101100110000101101110011001110111001000101101011100100110101101100111011100100110010101111010011101100110000101101110011001110111001001111101
5. Go to dcode.fr for cipher identification & decryption.
6. Cipher Identifier –> ASCII Code Decrypt –> Affine Cipher Decrypt –> Flag
sun{exterminate-exterminate-exterminate}