Task

OTP encryption of the message “attack at dawn” is 09e1c5f70a65ac519458e7e53f36. Use the same OTP key to encrypt “attack at dusk”. Flag is not in a standard format

Solution

With known plaintext “attack at dawn” and known ciphertext 09e1c5f70a65ac519458e7e53f36 we get the OTP key by XOR: 6895b196690e8c30e07883844858. Then we just XOR “attack at dusk” wth the obtained key and we get the solution in CyberChef

09e1c5f70a65ac519458e7f13b33

Solved by jomo & petrosyan