My take on generating passwords in PowerShell, based on what I've found here and in the Internets:
#Requires -Version 4.0
[CmdletBinding(PositionalBinding=$false)]
param (
[Parameter(
Mandatory = $false,
HelpMessage = "Minimum password length"
)]
[ValidateRange(1,[int]::MaxValue)]
[int]$MinimumLength = 24,
[Parameter(
Mandatory = $false,
HelpMessage = "Maximum password length"
)]
[ValidateRange(1,[int]::MaxValue)]
[int]$MaximumLength = 42,
[Parameter(
Mandatory = $false,
HelpMessage = "Characters which can be used in the password"
)]
[ValidateNotNullOrEmpty()]
[string]$Characters = '1234567890qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM@#%*-_+:,.'
)
(1..(Get-Random -Minimum $MinimumLength -Maximum $MaximumLength) `
| %{ `
$Characters.GetEnumerator() | Get-Random `
}) -join ''
I preferred this over using System.Web, not to introduce dependencies, which could change with .Net / .Net Core versions.
My variation also allows random password length (in specified range), is fairly concise (apart from the parameters section, which is quite verbose, to enforce some validations and provide defaults) and allows character repetitions (as opposite to the code in the question, which never repeats the same character).
I understand, that this does not guarantee a digit in the password. This however can be addressed in different ways. E.g. as was suggested, to repeat the generation until the password matches the requirements (contains a digit). My take would be:
- Generate a random password.
- If it does not contain a digit (or always):
- Use a random function to get 1 random digit.
- Add it to the random password.
- Randomize the order of the result (so the digit is not necessarily always at the end).
Assuming, that the above script would be named "Get-RandomPassword.ps1", it could look like this:
$pass = .\Get-RandomPassword.ps1
$pass += (0..9 | Get-Random)
$pass = (($pass.GetEnumerator() | Get-Random -Count $pass.Length) -join '')
Write-Output $pass
This can be generalized, to enforce using any character category:
$sets = @('abcdefghijklmnopqrstuvwxyz', 'ABCDEFGHIJKLMNOPQRSTUVWXYZ', '0123456789', '()-_=+[{]};:''",<.>/?`~')
$pass = .\Get-RandomPassword.ps1 -Characters ($sets -join '')
foreach ($set in $sets) {
$pass += ($set.GetEnumerator() | Get-Random)
}
$pass = (($pass.GetEnumerator() | Get-Random -Count $pass.Length) -join '')
Write-Output $pass
