1. A453 Exemplar Password Program using VBA
Mr Travi
Royal Grammar School
No 1

2. The basic requirements
Input a password
Is the password between 6 and 12 characters long
No reject and return to Stage 1
Yes output message and write the password to the spreadsheet file
Check each character of the password in turn
Is the character lower case if yes add 1 to the lower character counter
Is the character upper case if yes add 1 to the upper character counter
Is the character a number if yes add 1 to the numeric character counter
Is the character non numeric or text if yes add 1 to the punctuation character counter
If 1 different character type is used then the password status is set to weak
i.e. if lower characters are greater than 1 and upper , numeric and punctuation characters are less than
If 2 different character types are used then the password status is set to medium
If 3 different character types are used then the password status is set to strong
If 4 different character types are used then the password status is set to extra strong
List of passwords are stored in an array and results showing whether weak, medium, strong or extra strong are displayed in a spreadsheet
Select a password to amend and change it
Search a password from within the array and replace it

3. Flow chart of the program
Start
Input a password
Is it greater than 6 characters
Is it greater than 6 characters No
yes
Is it greater than 12 characters

4. Flow chart of the program
Is the character lcase or lowercase ?
lowers = lowers +1
yes No
Is the character ucase or Uppercase ?
Uppers= Uppers+1
Yes
Is the character Numeric ?
Numbers = Numbers + 1
Output password OK and write to spreadsheet file
Set Counter, uppers, lowers, numerics
Puncts to Zero No
For each character in password No
Punct = punct + 1
Yes
Is the character not lcase or ucase or numeric?

5. REPEAT
INPUT the password
len=length of password
IF len <6 OR len >12 THEN
PRINT suitable error message
UNTIL len >=6 and <=12
PRINT password OK
Initialise upper, lower, puncts and number to 0
FOR i = 1 TO len
For Counter = 1 To Len(ValidPassword(howmanypasswords))
Select Case Asc(Mid(ValidPassword(howmanypasswords), Counter, 1))
Case 47 To 57
numerics = numerics + 1
Case 65 To 90
uppers = uppers + 1
Case 97 To 122
lowers = lowers + 1
Case Else
puncts = puncts + 1
End Select
Next Counter
If uppers > 0 And lowers > 0 And puncts > 0 And numerics > 0 Then
passwordstatus = "Extra Strong"
ElseIf uppers > 0 And lowers > 0 And numerics > 0 Then
passwordstatus = "Strong"
ElseIf alphas > 0 And (puncts > 0 Or numerics > 0) Then
passwordstatus = "Medium"
ElseIf uppers > 0 And lowers > 0 Then
passwordstatus = "Medium“
Else
passwordstatus = "Weak“
Endif No
All characters checked?
Password status = uppers, l+ owers, numerics + Puncts
Output password strength and write to file
Stop

6. Weak, Medium, Strong and Extra Strong identified: Weak Medium Strong
We need a test strategy to use during development to show that the solution works at each stage. Requirement: characters
Less than 6
6 exactly
>6 and <12
12 exactly
More than 12
MrTra
MrTrav
MrTravi
MrTravirocks
MrTraviuiopasd
5 characters should be rejected
6 characters, boundary, should be OK
7 characters, valid input should be OK
12 characters, boundary, should be OK
13 characters should be rejected
Weak, Medium, Strong and Extra Strong identified:
Weak
Medium Strong
Extra Strong
mrtravi
MRTRAVI
123456
MrTravi
Awerty
Zwerty
3werty
3WERTY
Q23456
qwe456
1w3r5y
QW345Y
QW34ty
12erTY
MrT:O521542
01mL;*&EWa
All lower / upper case/ numeric:
weak reported
1 upper case, rest lower, also test A and Z accepted
Medium reported
All medium strength combinations and
With differing quantities of numbers and letters
Both cases and numeric used, Strong reported
All lower / upper case/ numeric/ punct:

7. Main program User Interface Set up variables
Validpasswords() is an array where the passwords entered by the user and written after they have passed a length test. This is a dynamic array and the results of this are written to the spreadsheet file
Password status records the results of the processing of the program to determine whether the password is weak, medium, strong or extra strong
User Interface
The user interface has
Txtinput – a textbox to allow the user to enter the password. In the properties I have set the passwordchar property to * to mimic the entry of passwords
The sub here updates each time a character is entered and outputs the number of characters that the password contains and what the status of the password being entered. For example

8. This shows what happens when just 2 characters have been entered the message displays ‘too short
Here 7 characters have been entered and the password length is OK
Here 14 characters have been entered and the password length is too long

9. The user interface has a label where the length of the password is displayed and the status of the password as it is enter
I have used several command buttons
CmdOk executes the main part of the program
CmdStartAgain will allow the user to reinitiate the program and toe enter the password again
CmdBonnet allows the user to say statistics about the password that has been entered, how lcase, ucase, mumeric and punctuation characters have been uesd
CmdBack makes the cmdbonnet visuble and lblstatus.visible property set to false
Lblstatus – 0nce the password has been accepted as valid the lblstatus label is set to visible and the password is displayed over the top of the text box where the password was entered into
Lblstrength the password status is displayed in this label.

10. I have entered a 5 character password and pressed CMDOk and invalid password has been returned
This initialises the array to make the array value equal to the number of passwords entered + 1

11. I have enclosed here with the program some main pseudocode
I have enclosed here with the program some main pseudocode. Msgbox txtinput.text displays a message and can help in the testing process
The sub accumulator can only run if the function which I have created lengthOk is true. Within the function there are 2 locally defined variables
atLeast6long and max12long which have to be true for the function I have created to be true

12. The accumulator module
This sub checks how many of each type of character appear in the password. The character is converted into its ASCII value
47 – 57 – numeric characters
– lower case characters
97 – 122 Upper case characters
All other ASCII characters are counted as punctuation marks
The sub calculates the value of the character for each password and adds up the total number of lower, upper, numerical and punctuation characters.
The password strength is processed using a nested if statement to work out if the password is weak, medium, strong or extra strong
The results of the program are written to the lblbonnet,caption and written to the sheet
This part of the sub writes the numbers of lowers, uppers, numeric and puncts to the sheets and the status result is written there

13. Howmanypasswords is a function created using a function with the spreadsheet and courting up how many entries are recorded in column A when the results of the program are being processed and written to
When the form is activated the sub init is initialised
This sets up the initial values and loads them into the variables

14. This loads the passwords into the array and writes the password to the spreadsheet file. The counter is set to the number of passwords already stored in the array.
This sub searches through the array to see if a password is in the array and then displays it.

15. Testing Section Test Data Expected Actual / Comment Test Data Expected
To see what happens when there are less than 6 characters
mrtra
Should be rejected
Was rejected
To see what happens if 6 characters are used
mrtrav
Should be accepted and processed as weak
Accepted and processed as weak
To see what happens when 7 characters are used
mrtravi
Test
Data
Expected
Actual / Comment
To see what happens when all numeric characters are used
521423
Should be accepted and status should be processed as weak
Was accepted and processed as weak
To see what happens if 7 characters including a capital letter are used
Mrtravi
Should be accepted and processed as medium
Accepted and processed as medium
To see what happens when a number and capital letters are used
3WERTY
Should be accepted and processed as medium

16. Testing Section Test Data Expected Actual / Comment
To see what happens when a combination of lower case , uppercase and numeric characters are used
QW34ty
Should be accepted as strong
Accepted and processed as strong
To see what happens when a combination of lower , upper case, numerical and punctuation characters are used
MrT:O521542
Should be accepted and processed as extra strong
Accepted and processed as extra strong
To perform a search through the array holding the passwords records
Record 2
Should display the password MrT:O521542
and highlight password status
is displayed as extra strong
Test
Data
Expected
Actual / Comment
To change a password held in the array
mrtravi
To change mrtravi to mrtravirocks
Password was changed

17. Test 1
I have entered mrtra as a password with 5 characters this has been rejected
I have entered mrtrav as a password with 6 characters this has been accepted and the status accepted as weak as this used all lower case characters
Test 2

18. Test 3
This shows that the password has been accepted and written to the spreadsheet
Test 4
The counts all the numeric characters and processes the password status as weak

19. Test 5
Here 1 capital letter and 6 lower case letters have been used and the password status has been processed as medium as expected
Test 6
This combination of uppercase letters and numbers has returned a medium password classification

20. Test 7
I have used here a combination of 2 uppercase, 2 lowercase letters and 2 numerical characters and this has returned a strong password
Test 8
I have used a combination of 2 uppercase, 2 lowercase letters, numerical and punctuation characters which as returned an extra strong password

21. First has to search for record mrtravi Record located
Test 9
Test 10
First has to search for record mrtravi
Record located

22. Password has been successfully searched and amended