How Can Regular Expressions Be Used to Validate Passwords with Advanced Security Rules?

Password Validation with Advanced Rules

When creating strong passwords, specific requirements are often imposed to enhance security. A common set of rules involves enforcing the inclusion of a minimum number of characters, a mix of upper and lowercase letters, at least one number, and special characters.

To ensure password compliance with these criteria, regular expressions (regex) are commonly employed. A previous attempt used the expression "(?=^.{8,}$)((?=.*d)|(?=.*W ))(?![.n])(?=.*[A-Z])(?=.*[a-z]).*$" to check for a minimum of eight characters, including at least one uppercase letter, one lowercase letter, and one number or special character.

However, to cater to all the specified requirements, the following enhanced regex expressions can be used:

• Minimum eight characters, at least one letter and one number: "^(?=.*[A-Za-z])(?=.*d)[A-Za-zd]{8,}$"
• Minimum eight characters, at least one letter, one number, and one special character: "^(?=.*[A-Za-z])(?=.*d)(?=.*[@$!%*#?&])[A-Za-zd@$!%*#?&]{8,}$"
• Minimum eight characters, at least one uppercase letter, one lowercase letter, and one number: "^(?=.*[a-z])(?=.*[A-Z])(?=.*d)[a-zA-Zd]{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-zd@$!%*?&]{8,}$"
• 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)(?=.*[@$!%*?&])[A-Za-zd@$!%*?&]{8,10}$"

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