I’ve created this PowerShell function that allows you generate any random strong password.
With this method, the caller is able to specify:
- The desired password length (minimum = 4)
- Whether or not to use lowercase characters
- Whether or not to use uppercase characters
- Whether or not to use numbers
- Whether or not to use special characters
- Whether or not to avoid using similar characters ( e.g. i, l, o, 1, 0, I)
The function ensures that each type of character (lowercase, uppercase, number and/or special) is included at least once in the password.
Examples of how to use this:
- GeneratePassword
Generates a password using the default settings (length of 8, using a combination of lowercase, uppercase and numbers, while avoiding similar characters), e.g. YeM2B98r - GeneratePassword 16
Generates a longer password using the default settings (length of 16, using a combination of lowercase, uppercase and numbers, while avoiding similar characters), e.g. 89p4758unWt2HDnp - GeneratePassword 4 $false $false
Generates a 4 digit numeric PIN code, e.g. 8298 - GeneratePassword 8 $true $true $true $true
Generates an extra strong password, (length of 8, using a combination of lowercase, uppercase, numbers and special characters, while avoiding similar characters), e.g. 9c+9P=#z - GeneratePassword 20 $true $true $true $true $false
Generates an extra strong password, (length of 20, using a combination of lowercase, uppercase, numbers and special characters with possible similar characters), e.g. YCi+R8?vVl1H!B+5hZU8
You can grab the script here (double-click it to copy):
function GeneratePassword() {
Param (
[int]$length = 8,
[bool] $includeLowercaseLetters = $true,
[bool] $includeUppercaseLetters = $true,
[bool] $includeNumbers = $true,
[bool] $includeSpecialChars = $false,
[bool] $noSimilarCharacters = $true
)
<#
(c) Morgan de Jonge CC BY SA
Generates a random password. you're able to specify:
- The desired password length (minimum = 4)
- Whether or not to use lowercase characters
- Whether or not to use uppercase characters
- Whether or not to use numbers
- Whether or not to use special characters
- Whether or not to avoid using similar characters ( e.g. i, l, o, 1, 0, I)
#>
# Validate params
if($length -lt 4) {
$exception = New-Object Exception "The minimum password length is 4"
Throw $exception
}
if ($includeLowercaseLetters -eq $false -and
$includeUppercaseLetters -eq $false -and
$includeNumbers -eq $false -and
$includeSpecialChars -eq $false) {
$exception = New-Object Exception "At least one set of included characters must be specified"
Throw $exception
}
#Available characters
$CharsToSkip = [char]"i", [char]"l", [char]"o", [char]"1", [char]"0", [char]"I"
$AvailableCharsForPassword = $null;
$uppercaseChars = $null
for($a = 65; $a -le 90; $a++) { if($noSimilarCharacters -eq $false -or [char][byte]$a -notin $CharsToSkip) {$uppercaseChars += ,[char][byte]$a }}
$lowercaseChars = $null
for($a = 97; $a -le 122; $a++) { if($noSimilarCharacters -eq $false -or [char][byte]$a -notin $CharsToSkip) {$lowercaseChars += ,[char][byte]$a }}
$digitChars = $null
for($a = 48; $a -le 57; $a++) { if($noSimilarCharacters -eq $false -or [char][byte]$a -notin $CharsToSkip) {$digitChars += ,[char][byte]$a }}
$specialChars = $null
$specialChars += [char]"=", [char]"+", [char]"_", [char]"?", [char]"!", [char]"-", [char]"#", [char]"$", [char]"*", [char]"&", [char]"@"
$TemplateLetters = $null
if($includeLowercaseLetters) { $TemplateLetters += "L" }
if($includeUppercaseLetters) { $TemplateLetters += "U" }
if($includeNumbers) { $TemplateLetters += "N" }
if($includeSpecialChars) { $TemplateLetters += "S" }
$PasswordTemplate = @()
# Set password template, to ensure that required chars are included
do {
$PasswordTemplate.Clear()
for($loop = 1; $loop -le $length; $loop++) {
$PasswordTemplate += $TemplateLetters.Substring((Get-Random -Maximum $TemplateLetters.Length),1)
}
}
while ((
(($includeLowercaseLetters -eq $false) -or ($PasswordTemplate -contains "L")) -and
(($includeUppercaseLetters -eq $false) -or ($PasswordTemplate -contains "U")) -and
(($includeNumbers -eq $false) -or ($PasswordTemplate -contains "N")) -and
(($includeSpecialChars -eq $false) -or ($PasswordTemplate -contains "S"))) -eq $false
)
#$PasswordTemplate now contains an array with at least one of each included character type (uppercase, lowercase, number and/or special)
foreach($char in $PasswordTemplate) {
switch ($char) {
L { $Password += $lowercaseChars | Get-Random }
U { $Password += $uppercaseChars | Get-Random }
N { $Password += $digitChars | Get-Random }
S { $Password += $specialChars | Get-Random }
}
}
return $Password
}
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
