Bitcoin Forum

I was chatting with a fellow developer at work today and he was asking about nLockTime, and as I was explaining it to him, it occurred to me if it would be possible to also have nLockSpace, which would lock a transaction to a specified set of x,y geo coordinates.

I take that you are imagine implementing this based on IP addresses ? This makes no sense as lots of IPs are dynamically attributed, lots of devices are constantly changing its position, and you would need all the ISPs in the world to collaborate with providing the geographical address of a given client that is using a certain IP at a certain moment.

No based upon lat/lng

For instance:

Walt Disney World is at:28.38602,-81.563873

https://maps.google.com/maps?q=Walt+Disney+World+Resort,+Lake+Buena+Vista,+FL&hl=en&ll=28.38602,-81.563873&spn=0.010704,0.013797&sll=28.480763,-81.368866&sspn=0.005347,0.006899&oq=walt+dis&t=m&z=16&iwloc=A

With gps we can get (last I heard) within 3x3 yards with commercial gps.

Damn you BitCoin Protocol, you keep surprising me.

This would be a privacy issue, because then the whole blockchain would know where you were at a given time, forever. Also What use case?

I don't get it, who would expose himself like that ? Combining nLocktime with this imaginary nLockspace is a serious personal security issue. Using nLockspace alone solves what exactly ?

Combined with nLockTime you could for instance only release a transaction at a given time and space.

Treasure hunts?

Dunno just an idea....

That would be a very boring hunt (i.e. not a hunt at all) for those that know bitcoin.

Not if the coordinates are hashed...

Imagine your great great grandchildren being able to go to a physical location that you went to years before and being able to see a picture of you that only they could see by knowing the coordinates and time.

Describe things in more detail please. You certainly mean something more here, otherwise this is instantly crackable. I'm still missing the step where you claim the transaction, does it involve using a device that spits your current coordinates ? How do you validate that ?

So we currently have nLockTime which for purposes of this conversation lock a transaction until a certain date and time.

Well... combined with nLockSpace a transaction would be locked so that it would not release until a certain date and time and physical location (again via gps x,y coordinates).

The purpose of nLockSpace would be to confine a transaction to a specified location on earth (within a certain degree of error, i.e. a few feet here or there), also given the correct time coordinates via nLockTime.

The data contained in the transaction (to be unlocked) does not necessarily have to be money/bitcoin but a message, for instance a video, audio or picture of you at that location months, years or decades later.

Today we have pictures with geo location embedded in them, well.... what if the picture of you existed at the location that you actually took it?

No.

It's possible for me to know exactly where on Earth I am, via GPS.

However, in order for Bitcoin - or any other blockchain-based ledger, for that matter - to support a feature like this, I need to be able to prove to the network that I'm there.

How do you propose this would be done?

The lock time operates on the network's rough agreement of the passage of time/the passage of blocks.  The network has no way to come to any sort of agreement, not even a rough one, on your location.