Dvdes-631 !!install!!
f(user_key) -> bool
We see the flag format, confirming the binary will simply puts the flag once the right key is supplied. dvdes-631
We start from the expected ciphertext:
MAGIC = 0x5A5A5A5A5A5A5A5A sub0 = 0x1F2E3D4C5B6A7988 user_key = ((sub0 ^ MAGIC) & 0xFFFFFFFFFFFFFFFF) >> 1 | ((sub0 ^ MAGIC) & 1) << 63 f(user_key) -> bool We see the flag format,
