no, not like zero coin...

its more of a virtual Cassius that never has to interact with the blockchain, until opened.

so I send you a private key that I can prove I have never seen and you can verify this, and you can choose to send on or open, then use as normal

but if we could do this, it would take all the pressure of the blockchain, miners, I could just email you my SEC and you can confrim yourself everything is good!

infact....this may be a problem for BITCOIN as miners would not be needed....or very rarely needed....

Holy grail if you could figure it out .... been grinding the old grey matter on this one for over 2 years now 

... the "Virtual Casascius" concept angle is interesting.

Yes. You could prove that it's never been spent, not that it's never been seen. The way to do this is by using a public ledger of digitally signed transactions.

Thinking forward, it may be possible to prove it's never been seen by using quantum cryptography.

But then after coin is traded varios users will have access to the sme 'unopened code'
Anyone along the way can spend it...

ok, so open, they need to interface with the client to get the opener code, once they have done this the client logs that coin and the opener code is not available to anyone else, but the code is only delivered once and destroyed and the SEC is opened at that time. Without the code no one esle can open their SEC, even though they have it

brainstorm on this idea to give us our inert cash that we need so badly:
https://bt.irlbtc.com/view/191175.0
You can skip over the first section which just says the maybe obvious reasons why

yes it does sort of end up where it started when you think it through....

It's fun to see people batting these ideas around because a great way to learn about a topic is by picking a problem and turning it over and over in your head.   Once you dig into the math of this, here's what you'll find:  there are only 2 ways to simultaneously ensure someone controls a piece of information and yet hasn't exercised that control.

1.  A trusted party
In this case, whoever runs the Chinese Code box would be able to lie about whether or not the box had been opened.  So if you find an entity you are willing to trust not to lie, the system can work.

2.  Some sort of p2p consensus methodology
This is in fact the central problem that the blockchain itself solves.  Its assumption (that computing power costs something, and that people wanting the system to work can out-compute those who want to exploit or destroy it) is an extremely narrow one, and that makes it very reliable.  If you were willing to accept different assumptions, for example that multiple known parties can be trusted not to collude, you could build a different sort of p2p consensus mechanism (like Ripple).

In short, the entire point of Bitcoin is that it answers this one question, and it answers it with the blockchain.  So if you try to recreate something with the same characteristics outside of the blockchain, you either have to accept different assumptions, or reinvent the blockchain.  And it's difficult to imagine a solution with lower built-in trust than Bitcoin's.

But don't take my word for it!  Keep turning the problem over your head until you understand why this must be the case.  If you do, you'll end up with a deeper understanding of Bitcoin than the vast majority of its fans.