How to create a legally valid timestamp of unpublished game artwork

Question

Before publishing promotional material of my first indie game I wanted to mark all my artwork with a legally valid timestamp.

There are two ways I know to do this:

 1 go to a sollecitor/lawyer and pay for them to certify the document
 2 use an online webservice to mark any given file/folder readable to the service

Anyone has already done this and if yes how (e.g. which website have you used? which type of solecitor have you contacted? etc..)?

I am doing all this because I have prepared a kickstarter video that I wanted to publish in these days to ask for some additional funds to complete my game and, as it contains sequences of the game, I am at the same time worried about publishing it (somebody might copy the characters as I say in the video that I would like to do also a comic book series based on those characters). I guess that "eCO" (or something similar) becomes a must in this case right?

Kind Regards

PS: I know that there is always the good old "send yourself a mail with a stamp and a date" but is not very strong as proof.

Answer 1

When your intention is to secure copyright by proving that you published your work first, and you don't want to pay for a certification by a 3rd party, just put your work on the web.

The internet wayback machine is often used as evidence how a website looked at a past date and what content it had.

Answer 2

while not quite the answer you search, just a little word of advice I learn recently : one of my friend's father is lawyer specialized in corporation business, and he told me to launch an alpha version, shows a demo, or even just show off to friend and family the concept of your game as early as possible as an Indie game dev. What you want to do is to make them sign a form prior to showing them. You write down that your working title is confidential, that they cant talk about it blablabla. The important part of that document is the date, as it serve as a proof that you were working on this project at the date shown on the document, and that you have a person who can attest to it.