You are close, but the parameter you pass to SecureStringToBSTR
must be a SecureString
. You appear to be passing the result of ConvertFrom-SecureString
, which is an encrypted standard string. So call ConvertTo-SecureString
on this before passing to SecureStringToBSTR
.
$SecurePassword = ConvertTo-SecureString $PlainPassword -AsPlainText -Force
$BSTR = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($SecurePassword)
$UnsecurePassword = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($BSTR)