what will be the problem if allowing all characters in permitted_uri_chars

[eluser]jayapalchandran[/eluser]

Code:

$config['permitted_uri_chars'] = '+=\a-z 0-9~%.:_-';

What will happen if i am allowing +=/ or some more chars?

I would like to send and receive base64 of an email address as an unique identification and when i do base64 i can see = appearing mostly as the last character.

so i want to use = in uri. and it is working well.

What will be the security risk?