Password regex Java
Password regular expression can be used to verify that a password provided is strong enough to provide better protection against bot brute force attacks. This method, however, does not guarantee that a password will have enough entropy to be completely safe.
Strong password regex
The regular expression below cheks that a password:
- Has minimum 8 characters in length. Adjust it by modifying {8,}
- At least one uppercase English letter. You can remove this condition by removing (?=.*?[A-Z])
- At least one lowercase English letter. You can remove this condition by removing (?=.*?[a-z])
- At least one digit. You can remove this condition by removing (?=.*?[0-9])
- At least one special character, You can remove this condition by removing (?=.*?[#?!@$%^&*-])
Pattern.compile("^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])(?=.*?[#?!@$%^&*-]).{8,}$")
Enter a text in the input above to see the result
Example code in Java:
import java.util.regex.Pattern;
public class Main {
public static void main(String []args) {
// Validate strong password
boolean isMatch = Pattern.compile("^(?=.*?[A-Z])(?=.*?[a-z])(?=.*?[0-9])(?=.*?[#?!@$%^&*-]).{8,}$")
.matcher("-Secr3t.")
.find();
System.out.println(isMatch); // prints true
}
}
Notes on password regex validation
While this regex validation is better than nothing, in situations when additional security is needed you should also check the password entered for a set of commonly used passwords like:
- .Qwerty1
- !Q1w2e3r4
- etc
One good list can be found here.
