Password Strength Expression

Question

It's been a while since I've had to use regular expressions.

Can someone explain this to me in layman's terms?

^(?=.{8,30})(?=.*[^A-Za-z])(?=.*[A-Z])(?=.*[a-z]).*

Answer 1

These are all assertions...

^ = starting from the beginning of the string...
(?=.{8,30}) = there is a string that is at least 8 characters long... (the upper bound of 30 cannot work this way)
(?=.*[^A-Za-z]) = somewhere in the string, there is at least one non-alphabetic character...
(?=.*[A-Z]) = somewhere in the string, there is at least one uppercase character...
(?=.*[a-z]) = somewhere in the string, there is at least one lowercase character....

.* match anyting, provided that all the above conditions are met.

HTH
--mc

Answer 2

Thanks.

Answer 3

(?=.{8,30}) = there is a string that is at least 8 characters long... (the upper bound of 30 cannot work this way)

Mario has a point...the above fails. To enforce the thirty character limit change the pattern to this:

^(?!.{31})(?=.{8})(?=.*[^A-Za-z])(?=.*[A-Z])(?=.*[a-z]).*$

(?!.{31})  - Match invalidator, if it finds 31 characters it invalidates the match. Nothing returned
$ - END of line

 

To add to Mario's, correct, statement

.* Match anything, zero or more times.

 

 

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William Wegerson (www.OmegaCoder.Com )

Answer 4

This pattern surely limits 30 chars and also accepts one or more numeral, small case and upper case alphabets.

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Regards, Rule the Codes and Code New Rules

Answer 5

great stub !!

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Vedigoundan Gurunathan

Answer 6

Very good !

Answer 7

Hi LarryEis,

Use the below expression,

^(?!.{31})(?=.{8})(?=.*[^A-Za-z])(?=.*[A-Z])(?=.*[a-z]).*$

^  = starting from the beginning of the string
(?=.{8,31}) = there is a string that is at least 8 characters long... (the upper bound of 31)
(?=.*[^A-Za-z]) = somewhere in the string, there is at least one non-alphabetic character
(?=.*[A-Z]) = somewhere in the string, there is at least one uppercase character
(?=.*[a-z]) = somewhere in the string, there is at least one lowercase character

Thanks

Roozan Bharucha

MCT, MCPD Windows Frmwk 4.0

Answer 8

This regex can also be helpful:

{8,15}$)(?=.*\d)((?=.*\W+)|(?=.*[A-Z]))(?![.\n]).*$

 

This is according to the standards which asks for minimum 8 to maximum 15 characters

One mandatory UpperCase Alphabet,

One mandatory LowerCase Alphabet,

One mandatory Number.

Answer 9

Yes , I agree with this ?= is the condition if the case is this then whats the result

\ is the escape case

[A-Z] any character between A -Z

* any case i.e small or capital letters

8-15 strength of the letter

Answer 10

Assert a string is 8 or more characters:
(?=.{8,})

Assert a string contains at least 1 lowercase letter (zero or more characters followed by a lowercase character):
(?=.*[a-z])

Assert a string contains at least 1 uppercase letter (zero or more characters followed by an uppercase character):
(?=.*[A-Z])

Assert a string contains at least 1 digit:
(?=.*[\d])

Assert a string contains at least 1 special character:
(?=.*[\W])

Assert a string contains at least 1 special character or a digit:
(?=.*[\d\W])

Answer 11

Regular expressions are one of those things where you have to keep in practise as it could become quite complicated.. But if you don't use it for a while and suddenly jump into it again, it all comes back..

Answer 12

Please visit following link:

http://www.zorched.net/2009/05/08/password-strength-validation-with-regular-expressions/

Answer 13

I need one for

Minimum of 8 (eight) characters and at least 1 non-alphanumeric characters.

Is it right?

^(?=.{8,})(?=.*[^A-Za-z])*

Answer 14

Refer Following urls

http://www.zorched.net/2009/05/08/password-strength-validation-with-regular-expressions/

http://www.techpint.com/programming/regular-expression-check-password-strength

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Gehan Fernando Snr. Engineer Technology. AKLO Information Technologies (Pvt) Ltd. #58, 42nd Lane, 5th Floor, Wellawatta, Colombo 06, Sri Lanka. Phone: [phone] | Mobile: [phone]