@@ -94,13 +94,14 @@ the owner may sell their property to multiple people and there would be no way
94to determine who is the new owner. With the land registry, all you need to do is
94to determine who is the new owner. With the land registry, all you need to do is
95ask the registry which sale happened first, and that's the one that counts.
95ask the registry which sale happened first, and that's the one that counts.
97Again, Urbit is yours and it's forever. Trusting central registries
98Again, Urbit is yours and it's forever. Trusting central registries
98jeopardizes both. The keen reader will notice that the problem of determining
99jeopardizes both. The keen reader will notice that the problem of determining
99which key rotation happened first is exactly the double-spend problem that
100which key rotation happened first is exactly the double-spend problem that
100Satoshi solved with his proof of work algorithm for Bitcoin. His first block
101Satoshi solved with his proof of work algorithm for Bitcoin. His first block
101famously includes a newspaper headline to prove he didn't mine the block before
102famously includes a newspaper headline to prove he didn't mine the block before
102that date. In a beautiful duality, his own algorithm proves that he didn't mine
103that date. In a beautiful duality, his own algorithm proves that he didn't mine
103−it after that date.[^1]
104+it after that date.<sup><a href="#f1">[1]</a></sup>
105Some argue that blockchain is only good for money. This is myopic and is
106Some argue that blockchain is only good for money. This is myopic and is
106generally based on the experience that its most valuable application so far has
107generally based on the experience that its most valuable application so far has
@@ -120,6 +121,7 @@ on the network will listen to the blockchain for key data. Thus, we have global
120consistency, permanence, and self sovereignty. We know of no other solution
121consistency, permanence, and self sovereignty. We know of no other solution
121that can provide these properties.
122that can provide these properties.
123While small individually, the aggregate PKI data for all nodes on the
125While small individually, the aggregate PKI data for all nodes on the
124network may become very large. This is not an issue for comets because nobody
126network may become very large. This is not an issue for comets because nobody
125needs to store comet keys except for those which they're talking with, and even
127needs to store comet keys except for those which they're talking with, and even
@@ -128,7 +130,7 @@ is a canonical set of keys, and somebody must store that. There are about
1282<sup>32</sup>, or 4 billion planets. If the PKI data is about 100 bytes for
1302<sup>32</sup>, or 4 billion planets. If the PKI data is about 100 bytes for
129each planet, this is about 400 GB of data. This may be more than most users wish
131each planet, this is about 400 GB of data. This may be more than most users wish
130to store, but it's small enough that it would be very cheap for someone to host
132to store, but it's small enough that it would be very cheap for someone to host
131−this data for many users[^3].
133+this data for many users<sup><a href="#f3">[3]</a></sup>.
133This information is currently stored directly on the Ethereum 1.0 blockchain,
135This information is currently stored directly on the Ethereum 1.0 blockchain,
134but as is well understood in blockchain circles this approach will not scale
136but as is well understood in blockchain circles this approach will not scale