Javascript – Regex for password must contain at least eight characters, at least one number and both lower and uppercase letters and special characters

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I want a regular expression to check that:

A password contains at least eight characters, including at least one number and includes both lower and uppercase letters and special characters, for example #, ?, !.

It cannot be your old password or contain your username, "password", or "websitename"

And here is my validation expression which is for eight characters including one uppercase letter, one lowercase letter, and one number or special character.

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

How can I write it for a password must be eight characters including one uppercase letter, one special character and alphanumeric characters?

Best Answer

Minimum eight characters, at least one letter and one number:

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

Minimum eight characters, at least one letter, one number and one special character:

"^(?=.*[A-Za-z])(?=.*\d)(?=.*[@$!%*#?&])[A-Za-z\d@$!%*#?&]{8,}$"

Minimum eight characters, at least one uppercase letter, one lowercase letter and one number:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]{8,}$"

Minimum eight characters, at least one uppercase letter, one lowercase letter, one number and one special character:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$"

Minimum eight and maximum 10 characters, at least one uppercase letter, one lowercase letter, one number and one special character:

"^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,10}$"

Related Solutions

C# – Regular expression to check if password is “8 characters including 1 uppercase letter, 1 special character, alphanumeric characters”

The regular expression you are after will most likely be huge and a nightmare to maintain especially for people who are not that familiar with regular expressions.

I think it would be easier to break your regex down and do it one bit at a time. It might take a bit more to do, but I am pretty sure that maintaining it and debugging it would be easier. This would also allow you to provide more directed error messages to your users (other than just Invalid Password) which should improve user experience.

From what I am seeing you are pretty fluent in regex, so I would presume that giving you the regular expressions to do what you need would be futile.

Seeing your comment, this is how I would go about it:

Must be eight characters Long: You do not need a regex for this. Using the .Length property should be enough.
Including one uppercase letter: You can use the [A-Z]+ regular expression. If the string contains at least one upper case letter, this regular expression will yield true.
One special character: You can use either the \W which will match any character which is not a letter or a number or else, you can use something like so [!@#] to specify a custom list of special characters. Note though that characters such as $, ^, ( and ) are special characters in the regular expression language, so they need to be escaped like so: \$. So in short, you might use the \W.
Alphanumeric characters: Using the \w+ should match any letter and number and underscore.

Take a look at this tutorial for more information.

Python Regex: password must contain at least one uppercase letter and number

We can use the pattern '\d.*[A-Z]|[A-Z].*\d' to search for entries that have at least one capital letter and one number. Logically speaking there are only two ways that a capital letter and a number can appear in a string. Either the letter comes first and the number after or the number first and the letter after.

The pipe | indicates 'OR', so we will look at each side separately. \d.*[A-Z] matches a number that is followed by a capital letter, [A-Z].*\d matches any capital letter that is followed by a number.

words = ['Password1', 'password2', 'passwordthree', 'P4', 'mypassworD1!!!', '898*(*^$^@%&#abcdef']
for x in words:
    print re.search('\d.*[A-Z]|[A-Z].*\d', x)
#<_sre.SRE_Match object at 0x00000000088146B0>
#None
#None
#<_sre.SRE_Match object at 0x00000000088146B0>
#<_sre.SRE_Match object at 0x00000000088146B0>
#None

Best Answer

Related Solutions

C# – Regular expression to check if password is “8 characters including 1 uppercase letter, 1 special character, alphanumeric characters”

Python Regex: password must contain at least one uppercase letter and number

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