darkCON CTF 2021 - CyberDark0x01: ShitComp [ RE ]

solver_shitcomp.py

from Crypto.Util.number import bytes_to_long as b2l

f=open("Installer.shitty","r")
plain=f.read()
f.close()
v4 = "CyberDarkIsACoolGameAndIWannaPlayIt"
file = ""
for i in range(0,len(plain),3):
	v8 = ord(v4[i%len(v4)])
	v9 = v8
	v11 = (v9>>4)&0xff
	for j in range(0xff+1):
		v10 = (j^v8)&0xf
		tmp = v10 | 16 * ( v11 ^ ((j>>4)&0xff))
		if(tmp==ord(plain[i])):
			v8 = ord(v4[(i+2)%len(v4)])
			v9 = v8
			v11 = (v9>>4)&0xff
			for k in range(0xff+1):
				v10 = (k^v8)&0xf
				tmp2 = v10 | 16 * ( v11 ^ ((k>>4)&0xff))
				if(tmp2==ord(plain[i+2])):
					v8 = ord(v4[(i+1)%len(v4)])
					v9 = v8
					v11 = (v9>>4)&0xff
					for l in range(0xff+1):
						v10 = (l^v8)&0xf
						tmp3 = v10 | 16 * ( v11 ^ ((l>>4)&0xff))
						if(tmp3==ord(plain[i+1])):
							file+=chr(j)*b2l(chr(l)+chr(k))
							break
					break
			break

file+="\x00"*15
f=open("original","wb")
f.write(file)
f.close()