Regex to validate password strength

Question

My password strength criteria is as below :

• 8 characters length
• 2 letters in Upper Case
• 1 Special Character (!@#$&*)
• 2 numerals (0-9)
• 3 letters in Lower Case

Can somebody please give me regex for same. All conditions must be met by password .

Answer 1

Another solution:

import re

passwordRegex = re.compile(r'''(
    ^(?=.*[A-Z].*[A-Z])                # at least two capital letters
    (?=.*[!@#$&*])                     # at least one of these special c-er
    (?=.*[0-9].*[0-9])                 # at least two numeric digits
    (?=.*[a-z].*[a-z].*[a-z])          # at least three lower case letters
    .{8,}                              # at least 8 total digits
    $
    )''', re.VERBOSE)

def userInputPasswordCheck():
    print('Enter a potential password:')
    while True:
        m = input()
        mo = passwordRegex.search(m) 
        if (not mo):
           print('''
Your password should have at least one special charachter,
two digits, two uppercase and three lowercase charachter. Length: 8+ ch-ers.

Enter another password:''')          
        else:
           print('Password is strong')
           return
userInputPasswordCheck()

Answer 2

I would suggest adding

(?!.*pass|.*word|.*1234|.*qwer|.*asdf) exclude common passwords

Answer 3

You can use zero-length positive look-aheads to specify each of your constraints separately:

(?=.{8,})(?=.*\p{Lu}.*\p{Lu})(?=.*[!@#$&*])(?=.*[0-9])(?=.*\p{Ll}.*\p{Ll})

If your regex engine doesn't support the \p notation and pure ASCII is enough, then you can replace \p{Lu} with [A-Z] and \p{Ll} with [a-z].

Answer 4

You can do these checks using positive look ahead assertions:

^(?=.*[A-Z].*[A-Z])(?=.*[!@#$&*])(?=.*[0-9].*[0-9])(?=.*[a-z].*[a-z].*[a-z]).{8}$

Rubular link

Explanation:

^                         Start anchor
(?=.*[A-Z].*[A-Z])        Ensure string has two uppercase letters.
(?=.*[!@#$&*])            Ensure string has one special case letter.
(?=.*[0-9].*[0-9])        Ensure string has two digits.
(?=.*[a-z].*[a-z].*[a-z]) Ensure string has three lowercase letters.
.{8}                      Ensure string is of length 8.
$                         End anchor.

Answer 5

import re

RegexLength=re.compile(r'^\S{8,}$')
RegexDigit=re.compile(r'\d')
RegexLower=re.compile(r'[a-z]')
RegexUpper=re.compile(r'[A-Z]')


def IsStrongPW(password):
    if RegexLength.search(password) == None or RegexDigit.search(password) == None or RegexUpper.search(password) == None or RegexLower.search(password) == None:
        return False
    else:
        return True

while True:
    userpw=input("please input your passord to check: \n")
    if userpw == "exit":
        break
    else:
        print(IsStrongPW(userpw))

Answer 6

Password must meet at least 3 out of the following 4 complexity rules,

[at least 1 uppercase character (A-Z) at least 1 lowercase character (a-z) at least 1 digit (0-9) at least 1 special character — do not forget to treat space as special characters too]

at least 10 characters

at most 128 characters

not more than 2 identical characters in a row (e.g., 111 not allowed)

'^(?!.(.)\1{2}) ((?=.[a-z])(?=.[A-Z])(?=.[0-9])|(?=.[a-z])(?=.[A-Z])(?=.[^a-zA-Z0-9])|(?=.[A-Z])(?=.[0-9])(?=.[^a-zA-Z0-9])|(?=.[a-z])(?=.[0-9])(?=.*[^a-zA-Z0-9])).{10,127}$'

(?!.*(.)\1{2})

(?=.[a-z])(?=.[A-Z])(?=.*[0-9])

(?=.[a-z])(?=.[A-Z])(?=.*[^a-zA-Z0-9])

(?=.[A-Z])(?=.[0-9])(?=.*[^a-zA-Z0-9])

(?=.[a-z])(?=.[0-9])(?=.*[^a-zA-Z0-9])

.{10.127}