Not sure if this is even possible but I have been looking at using Regex to get an email address that is in Hex. Basically this is to build up some of my automated forensic tools but I am having problems on making a suitable Regex algorithm. Regex for email: /^([a-z0-9_.-]+)@([\da-z.-]+).([a-z.]{2,6})$/ Hex values: @ = 40 . = 2E .com = 636f6d _ = 5f A/a = 41/61 [1] Z/z = 5a/7a - = 2d This is what I have got at the moment (it only takes into account lower case and .com). But it doesn't work! Have I messed something simple up? "/^([61-7a]+)40([61-7a]+)23(636f6d)$/" [1] I know email can only be lower case but I need to take uppercase into account too.