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

Question

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?

Answer 1

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}$" 

Answer 2

You may use this regex with multiple lookahead assertions (conditions):

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

This regex will enforce these rules:

• At least one upper case English letter, (?=.*?[A-Z])
• At least one lower case English letter, (?=.*?[a-z])
• At least one digit, (?=.*?[0-9])
• At least one special character, (?=.*?[#?!@$%^&*-])
• Minimum eight in length .{8,} (with the anchors)