[*] thong diep: amount=100&to=alice
[*] bat dau timing attack, khoi phuc 6 byte dau cua tag...
    byte 0 -> 08
    byte 1 -> 7a
    byte 2 -> 60
    byte 3 -> c2
    byte 4 -> ed
    byte 5 -> 2a
[*] khoi phuc : 087a60c2ed2a
[*] tag that  : 087a60c2ed2a
[*] khop?     : True (11.3s)
[+] timing attack THANH CONG, khong biet key

[*] cach lam dung: hmac.compare_digest (hang thoi gian).
    sai byte cuoi : 127 ns
    sai byte dau  : 127 ns
    => chenh lech khong tuyen tinh theo prefix -> khong con oracle thoi gian
