Crack Digital Physiognomy 1 831 -

void transform(char *src, char *dst) { int len = strlen(src); for (int i = 0; i < len; i++) { dst[i] = (src[i] ^ 0x42) + 0x13; } dst[len] = 0; reverse(dst); } We know: reverse( (input[i] ^ 0x42) + 0x13 ) == "831_physiognomy_cracked"

First, reverse target : "dekarc_demongysoihp_138" Crack Digital Physiognomy 1 831

$ python3 solve.py CTF{d1g1t4l_f4c3_831} $ ./physiognomy Enter digital physiognomy key: CTF{d1g1t4l_f4c3_831} Flag: CTF{d1g1t4l_f4c3_831} Matches expected output. Flag CTF{d1g1t4l_f4c3_831} Note: The number 831 appears as part of the intermediate constant string 831_physiognomy_cracked , likely referencing the challenge ID or a magic value. void transform(char *src, char *dst) { int len

Now for each char c in reversed target:

Let target = "831_physiognomy_cracked" . void transform(char *src

flag = ''.join(flag_chars) print(flag)

Run it: