I have the following problem I am trying to make a validation for ssh-keys (public) so that the customer has to give me a real ssh-key. Can someone tell me how to make the 'regex' so that this is correct? I have something like this: ssh-rsa AAAA[0-9A-Za-z+/]+[=]{0,3} ([^@]+@[^@]+)# but this does not work. Error: preg_match(): Delimiter must not be alphanumeric or backslash
Your regex might be fine. You should use a delimiter in your regex
$regex = '/ssh-rsa AAAA[0-9A-Za-z+\/]+[=]{0,3} ([^@]+@[^@]+)#/'