I can't even remember when or why I wrote this, but I needed to quickly and easily generate a password for something. I typically use PasswordMinder for this, but when I wrote this I just needed to generate a whole bunch of them for someone else and didn't need to keep them in my password database.

It is a relatively simple script that uses the RNGCryptoServiceProvider class in the System.Security.Cryptography namespace to generate the random sequence. It uses a default set of characters (see the script) and a default password length of 12.

generate-password.ps1:

param( 
[int] $len = 12,
[string] $chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_!@#$%^&*()_"
)
$bytes = new-object "System.Byte[]" $len
$rnd = new-object System.Security.Cryptography.RNGCryptoServiceProvider
$rnd.GetBytes($bytes)
$result = ""
for( $i=0; $i -lt $len; $i++ )
{
$result += $chars[ $bytes[$i] % $chars.Length ]	
}
$result

DISCLAIMER: I am not a crypto expert, so this might not be a very good implementation! It is meant to illustrate how you can do this stuff in PowerShell and not anything else.