These are the requirements but I guess it's too complicated for my regular expression skills...
. between 6 and 10 alphanum characters
. allowed A-Z,a-z,0-9,@,$,_
. Must begin with a letter
. Must contain at least one number
. cannot contain two consecutive identical characters
. cannot contain two consecutive identical numbers
I know the basic of regular expression such as [A-Za-Z] = characters only etc... but when it comes to consecutive character and stuff...
Try this
((?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[\W]).{6,20})
Description of above Regular Expression:
( # Start of group
(?=.*\d) # must contains one digit from 0-9
(?=.*[a-z]) # must contains one lowercase characters
(?=.*[A-Z]) # must contains one uppercase characters
(?=.*[\W]) # must contains at least one special character
. # match anything with previous condition checking
{6,20} # length at least 6 characters and maximum of 20
) # End of group
"/W" will increase the range of characters that can be used for password and pit can be more safe.
string pattern1 = @"^[a-zA-Z]([a-zA-Z])*"; //start and any number of characters
string pattern2 = @"[0-9]+"; //one number or more numbers
string pattern3 = @"[@#$%]*"; // special symbol allowed
string pattern4 = @"(.)\1";//consecutive characters
string pattern5 = @"^(.){6,10}$"; //min max
should you want to validate the password you can use groups to do soo ;
(?<a>[a-zA-Z])?(?<b>[0-9])?(?<c>[@%$#/\\\(\)])?
Will give you a match in any of the 3 groups (a,b and c)
uper and lower characters will be in group a
numeric characters will be in group b
and special characters will be in group c
you can use the regex.match.groups("a").count to see if any characters from group a could be found
if you find characters in all 3 groups, the password is strong.
