PowerShell - Decode System.Security.SecureString to readable password

Question

I want to decode the password from a System.Security.SecureString to a readable password.

$password = convertto-securestring "TestPassword" -asplaintext -force
$credentials = New-Object System.Net.NetworkCredential("TestUsername", $password, "TestDomain")

This code part works fine, I can use the $credentials object. But later in my code I need the password in a readable format. Because a methode needs the password in readable string. So I must decode the password back.

How it is possible to decode the password from the $credentials object?

Update

Not working:

$password = convertto-securestring "TestPassword" -asplaintext -force
$credentials = New-Object System.Net.NetworkCredential("TestUsername", $password, "TestDomain")

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

Answer 1

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