Get-Content C:\Scripts\Secrets\unlockusb.txt | Where-Object {$_.length -gt 0} | Where-Object {!$_.StartsWith("#")} | ForEach-Object {
    $var = $_.Split('=',2).Trim()
    New-Variable -Scope Script -Name $var[0] -Value $var[1]
}

$SecureString = ConvertTo-SecureString $mystring -AsPlainText -Force
Unlock-BitLocker -MountPoint "Z:" -Password $SecureString

#### in unlockucb.txt put below
### mystring=xxxxx