PowerShell – Decode System.Security.SecureString to readable password

Here you go:

$password = ConvertTo-SecureString 'P@ssw0rd' -AsPlainText -Force

$Ptr = [System.Runtime.InteropServices.Marshal]::SecureStringToCoTaskMemUnicode($password)
$result = [System.Runtime.InteropServices.Marshal]::PtrToStringUni($Ptr)
[System.Runtime.InteropServices.Marshal]::ZeroFreeCoTaskMemUnicode($Ptr)
$result 

P@ssw0rd