Download file is not file extension.
Open notepad.
Look like packet file.
file extension change '.pcap', then open wireshark.
Extract file at this packet.
treasure1 is png file but, not complete.
so, i think treasure1 add up 2,3.
<python code>
png = open("./result.png", 'w')
tr1 = open('./treasure1','rb')
tr2 = open('./treasure2','rb')
tr3 = open('./treasure3','rb')
bin_tr1 = tr1.read()
bin_tr2 = tr2.read()
bin_tr3 = tr3.read()
result = bin_tr1 + bin_tr2 + bin_tr3
print "[*] Complete!"
png.write(result)
png.close()
tr1.close()
tr2.close()
tr3.close()
encode find key at md5.
flag