Excel VB | random password generator

There are a few of way I like to create random passwords usually from a Filemaker server based database, for more security, but here is an Excel visual basic equivalent of what I use:

Random Password Generator

This code below generates passwords completely randomly.

Public Function RndPass(Length As Integer, Optional Lower As Boolean) As String

Dim Max As Integer
Dim Min As Integer

Dim RndPassLoop As String

Max = 126
Min = 48

Randomize Timer

If Length < 8 Then
Length = 8
End If

For i = 1 To Length
RndPassLoop = RndPassLoop & Chr(Int((Max - Min + 1) * Rnd + Min))
Next i

If Lower = False Then
RndPass = RndPassLoop
Else
RndPass = StrConv(RndPassLoop, vbLowerCase)
End If

End Function

‘add this code to a vb module
’syntax is RndPass(Length of password, True (lowercase) / Empty or False (both upper and lower)
‘RndPass(20,1) = 20 characters lower case

Random Letter Generator

This code below will generator code for a random letter or number based string.

Public Function RndPassP(Phrase As String) As String

Dim Max As Integer
Dim Min As Integer

Dim RndPassLoop As String

If Len(Phrase) < 12 Then
RndPassP = “Phrase too short - please choose something longer”
Exit Function
End If

If subStringCount(Phrase, “a”) + _
subStringCount(Phrase, “c”) + _
subStringCount(Phrase, “e”) + _
subStringCount(Phrase, “i”) + _
subStringCount(Phrase, “o”) + _
subStringCount(Phrase, “s”) + _
subStringCount(Phrase, “u”) + _
subStringCount(Phrase, “r”) < 4 Then

RndPassP = “Phrase does not include enough key letters - please choose another”
Exit Function
End If

Phrase = StrConv(Phrase, vbLowerCase)

Randomize Timer

RndPassLoop = Replace(Phrase, “a”, “@”)
Phrase = Replace(RndPassLoop, “b”, “8″)
RndPassLoop = Replace(Phrase, “e”, “3″)
Phrase = Replace(RndPassLoop, “i”, “!”)
RndPassLoop = Replace(Phrase, “o”, “0″)
Phrase = Replace(RndPassLoop, “s”, “$”)
RndPassLoop = Replace(Phrase, ” “, “”)
Phrase = Replace(RndPassLoop, “u”, ” * “)
RndPassLoop = Replace(Phrase, “r”, “£”)
Phrase = Replace(RndPassLoop, “M”, “M”)
RndPassLoop = Replace(Phrase, “N”, “N”)
Phrase = Replace(RndPassLoop, “T”, “T”)
RndPassLoop = Replace(Phrase, “X”, “X”)
Phrase = Replace(RndPassLoop, “G”, “G”)

Phrase = RndPassLoop & “:)”"”

RndPassP = Phrase

End Function

Function subStringCount(longString As String, subString As String) As Double
subStringCount = Len(longString) _
- Len(Application.Substitute(longString, subString, vbNullChar))
End Function

‘add this code to a vb module
’syntax is ‘RndPassP(string):
‘RndPassP (”I work in Property Finance”)

Let me know what you think about these and what sort of password system you use?

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You’re currently reading “Excel VB | random password generator”.

Published:: Monday, August 18th, 2008

Author:: Simon Page

Category:: Excel

Tags:: downloads, excel 2003, excel 2007, free, security, vb, vba, visual basic

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David Z April 3rd, 2009

I wrote a fairly simple macro that uses upper & lower case letters, numerals, and a few special characters (forcing one of each type). Below is VBA for a 10-character password

Sub PasswordGenerate() 'Creates a password 10 characters long 'with at least 1 upper & lower case letters, 1 number, and 1 special character ' 'Recorded by David Z, April 3, 2009 ' ' Dim l, x, c As Integer Dim p, p1, p2 As String


p = ""
'Force at least one of each character type

    c = RandBetween(35, 38) 'Special characters #, $, %, &

        p = p & Chr(c)

    c = RandBetween(48, 57) 'Number

        p = p & Chr(c)

    c = RandBetween(65, 90) 'Upper case

        p = p & Chr(c)

    c = RandBetween(97, 122) 'Lower case

        p = p & Chr(c)
'Create a string variable 6 characters long, randomizing characters, numbers, upper & lower case letters

    For l = 1 To 6

        x = Empty 'Just in case

        x = RandBetween(1, 4) 'Choose a random number

            If x = 1 Then c = RandBetween(35, 38) 'Specials

            If x = 2 Then c = RandBetween(48, 57) 'Numbers

            If x = 3 Then c = RandBetween(65, 90) 'Uppers

            If x = 4 Then c = RandBetween(97, 122) 'Lowers

        p = p & Chr(c) 'concatenate old password & random character

    Next l
'Now randomly re-arrange the characters in the password string

x = RandBetween(0, 9)

    p1 = Left(p, x)

    p2 = Right(p, Len(p) - x)
p = p2 & p1 'Password is ready!
Selection.Value = p

End Sub

Simon Page April 13th, 2009

Thanks David for that contribution!

okili July 20th, 2009

Unfortunately the randbetween function does not work for me (I have excel 2007)…

I tried to modify the function to get what I wanted but something went wrong, here is the code which i tried to use:

Function pass(Length As Integer)

Dim p As String
Dim c As Integer

p = “”

For i = 1 To Length
x = Int(Rnd * 2 + 1)
If x = 1 Then c = Chr(Int(48 + Rnd * (57 - 48)))
If x = 2 Then c = Chr(Int(65 + Rnd * (90 - 65)))
If x = 3 Then c = Chr(Int(97 + Rnd * (122 - 97)))
p = p & c
Next i

pass = p

End Function

Simon Page July 21st, 2009

Take it you mean you only have Excel 2003 as Randbetween works fine in Excel 2007. The equivalent of this is:

INT(RAND()*(b-a)+a)

So looks like you are almost there, here it is with corrections:

Dim p As String
Dim c As String

For i = 1 To Length

x = Int(Rnd() * 4)

If x = 1 Then c = Chr(Int(Rnd() * (57 - 48) + 48))
If x = 2 Then c = Chr(Int(Rnd() * (90 - 65) + 65))
If x = 3 Then c = Chr(Int(Rnd() * (120 - 97) + 97))

p = p & c

Next i

okili July 21st, 2009

Thank you for your answer, now it works well. I have Excel 2007, not 2003, the randbetween function does work in Excel main window but it does not in VB Editor, I don’t know why, probably something is wrong with installation. Fortunately the equivalent function does the same thing.
Now as I see I should have used Rnd() instead of just Rnd and another one is that I defined c as Integer (don’t know why :D ) not as string.

So finally, to sum up:
We got the simple and smart function, with the following syntax: pass(Length); it chooses randomly symbols from the following ranges: A-Z, a-z, 0-9; and creates the password of the defined length :)

Excel VB | random password generator

Random Password Generator

Random Letter Generator

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