VB.NET Password Complexity

[Deebee]

Strong passwords meet a number of requirements for complexity - including length and character categories - that make passwords more difficult for attackers to determine. Establishing strong password policies for your organization can help prevent attackers from impersonating users and can thereby help prevent the loss, exposure, or corruption of sensitive information.

In this tutorial, we will create a program that can determine if the inputted password is complex or not :)

Now, let's start this tutorial!

1. Let's start with creating a Windows Form Application for this tutorial by following the following steps in Microsoft Visual Studio: Go to File, click New Project, and choose Windows Application.

2. Next, add only one Button named Button1 and labeled it as "Submit" for determining the complexity of the password. Add one textbox named TextBox1 for inputting your desired password. Add two labels named Label1 labeled it as "Password is Complex:" and Label2 which is an empty string that has a boolean value for displaying the complexity. You must design your interface like this:

3. Import System.text.RegularExpressions.

We imported this namespace because it enables us to determine whether a particular string conforms to a regular expression pattern.

4. Create a function named ValidatePassword. Put this code in your code module:

1. Function
   
   ValidatePassword(
   
   ByVal
   
   pwd As
   
   String
   
   , Optional
   
   ByVal
   
   minLength As
   
   Integer
   
   =
   
   8
   
   , Optional
   
   ByVal
   
   numUpper As
   
   Integer
   
   =
   
   2
   
   , Optional
   
   ByVal
   
   numLower As
   
   Integer
   
   =
   
   2
   
   , Optional
   
   ByVal
   
   numNumbers As
   
   Integer
   
   =
   
   2
   
   , Optional
   
   ByVal
   
   numSpecial As
   
   Integer
   
   =
   
   2
   
   )
   
   As
   
   Boolean
   
2. 
   
3. ' Replace [A-Z] with \p{Lu}, to allow for Unicode uppercase letters.
   
4. Dim
   
   upper As
   
   New
   
   System.
   
   Text
   
   .
   
   RegularExpressions
   
   .
   
   Regex
   
   (
   
   "[A-Z]"
   
   )
   
5. Dim
   
   lower As
   
   New
   
   System.
   
   Text
   
   .
   
   RegularExpressions
   
   .
   
   Regex
   
   (
   
   "[a-z]"
   
   )
   
6. Dim
   
   number As
   
   New
   
   System.
   
   Text
   
   .
   
   RegularExpressions
   
   .
   
   Regex
   
   (
   
   "[0-9]"
   
   )
   
7. ' Special is "none of the above".
   
8. Dim
   
   special As
   
   New
   
   System.
   
   Text
   
   .
   
   RegularExpressions
   
   .
   
   Regex
   
   (
   
   "[^a-zA-Z0-9]"
   
   )
   
9. 
   
10. ' Check the length.
    
11. If
    
    Len(
    
    pwd)
    
    <
    
    minLength Then
    
    Return
    
    False
    
12. ' Check for minimum number of occurrences.
    
13. If
    
    upper.
    
    Matches
    
    (
    
    pwd)
    
    .
    
    Count
    
    <
    
    numUpper Then
    
    Return
    
    False
    
14. If
    
    lower.
    
    Matches
    
    (
    
    pwd)
    
    .
    
    Count
    
    <
    
    numLower Then
    
    Return
    
    False
    
15. If
    
    number.
    
    Matches
    
    (
    
    pwd)
    
    .
    
    Count
    
    <
    
    numNumbers Then
    
    Return
    
    False
    
16. If
    
    special.
    
    Matches
    
    (
    
    pwd)
    
    .
    
    Count
    
    <
    
    numSpecial Then
    
    Return
    
    False
    
17. 
    
18. ' Passed all checks.
    
19. Return
    
    True
    
20. End
    
    Function
    

Explanation

We have created ValidatePassword Function that has the following parameters of a password as string, minimum length of the password is 8, Capital Letter and Lower Letter must have a minimum of two letters, two digits of numbers, and must have a minimum of 2 special characters to make it complex. Then we have initialized variable upper to have capitalized letter, variable lower to have non-capitalized letter, variable number to have numerical inputs, and we used RegEx because it will hold the regular expression of not having a number or letter but to have a special character which it holds by variable special. Then it checks the length, if it will not have a minimum of 8 characters then it will return False as well as the other parameters. If it meets all the requirements, then it will display True.

5. Then, put this code to button1_click. This will display the output in boolean in Label2.

1. Label2.
   
   Text
   
   =
   
   ValidatePassword(
   
   TextBox1.
   
   Text
   
   )
   

Output:

Not a complex password

A complex password

Download the source code below and try it! :)

For more inquiries and need programmer for your thesis systems in any kind of programming languages, just contact my number below.

Best Regards,

Engr. Lyndon R. Bermoy

IT Instructor/System Developer/Android Developer

Mobile: 09079373999

Telephone: 826-9296

E-mail:[email protected]

Visit and like my page on Facebook at: Bermz ISware Solutions

Subscribe at my YouTube Channel at: SerBermz

Download