@@ -54,11 +54,13 @@ However, Urbit is yours and it's forever. You shouldn't have to change your name
5454every time you change your keys. So, we go back and take the other choice as well: you
5555must be able to change your keys.
5656
57+<a name="0"></a>
5758To change keys, you must sign a message with the old keys revoking them and
58−supplying the new ones[^0]. The question is what happens if the old keys also
59−sign a second set of new keys. This could happen if an attacker obtained your
60−old keys after the fact. This is important because one of the reasons to be able
61−to change your keys is to invalidate the old ones so that they have no power.
59+supplying the new ones<sup><a href="#f0">[0]</a></sup>. The question
60+is what happens if the old keys also sign a second set of new keys. This could
61+happen if an attacker obtained your old keys after the fact. This is important
62+because one of the reasons to be able to change your keys is to invalidate the
63+old ones so that they have no power.
6264
6365We have two options again: the PKI may be globally consistent or not. To be
6466globally consistent means that if you believe a name is bound to a set of keys,
@@ -108,13 +110,15 @@ signed before another without a central party. Blockchain was discovered by
108110someone trying to create digital money, and he needed that primitive, but that
109111doesn't mean that's all it's good for.
110112
113+<a name="2"></a>
111114Thus, we store our PKI data on a blockchain for our second kind of name:
112−[planets](/docs/glossary/planet). A planet is a 32-bit address which has key information stored on the
113−blockchain.[^2] The owner of a planet may broadcast new PKI data by adding it to
114−the blockchain. Any later messages by the old keys will be rejected, and
115−everyone on the network will listen to the blockchain for key data. Thus, we
116−have global consistency, permanence, and self sovereignty. We know of no other
117−solution that can provide these properties.
115+[planets](/docs/glossary/planet). A planet is a 32-bit address which has key
116+information stored on the blockchain.<sup><a href="#f2">[2]</a></sup>
117+The owner of a planet may broadcast new PKI data by adding it to the
118+blockchain. Any later messages by the old keys will be rejected, and everyone
119+on the network will listen to the blockchain for key data. Thus, we have global
120+consistency, permanence, and self sovereignty. We know of no other solution
121+that can provide these properties.
118122
119123While small individually, the aggregate PKI data for all nodes on the
120124network may become very large. This is not an issue for comets because nobody
@@ -162,34 +166,36 @@ are three other properties; pick any two:
162166
163167- Moons are permanent, not self sovereign, and plentiful.
164168
169+<a name="4"></a>
165170Fancifully, comets are wayward celestial bodies that are great for testing and
166171miscellaneous low-value things that won't last for long. Planets are where you
167172can build a home and shape it into anything you want it to be. People can always
168173find your planet; it's not going anywhere. Moons are useful for special
169174purposes, like storage, heavy industry, and anything else you might want to do
170−off-planet.[^4]
175+off-planet.<sup><a href="#f4">[4]</a></sup>
171176
172177
173−[^0]: Or the equivalent with a hierarchical key structure. In practice, you want
174− to have a master key which signs a junior key for everyday use. You use the
175− master key to rotate the junior key.
178+<a name="f0" href="#0">[0]</a>: Or the equivalent with a hierarchical key
179+structure. In practice, you want to have a master key which signs a junior key
180+for everyday use. You use the master key to rotate the junior key.
176181
177−[^1]: More strictly: it proves that he didn't mine it after the other blocks
178− currently on the Bitcoin blockchain. It only gives an ordering within the
179− chain, not a literal timestamp.
182+<a name="f1" href="#1">[1]</a>: More strictly: it proves that he didn't mine it
183+after the other blocks currently on the Bitcoin blockchain. It only gives an
184+ordering within the chain, not a literal timestamp.
180185
181−[^2]: In addition to planets, there are stars and galaxies. From a PKI
182− perspective they're treated exactly like planets, but on the network they
183− provide infrastructure services like routing.
186+<a name="f2" href="#2">[2]</a>: In addition to planets, there are stars and
187+galaxies. From a PKI perspective they're treated exactly like planets, but on
188+the network they provide infrastructure services like routing.
184189
185−[^3]: In practice, this will likely be an included service by your sponsoring
186− star. It could be a separate service, but it will be very cheap because it's
187− a commodity and the "cost of production" is very cheap. At any rate, it
188− should never rise above the capital cost of a 400GB hard drive.
190+<a name="f3" href="#3">[3]</a>: In practice, this will likely be an included
191+service by your sponsoring star. It could be a separate service, but it will be
192+very cheap because it's a commodity and the "cost of production" is very cheap.
193+At any rate, it should never rise above the capital cost of a 400GB hard drive.
189194
190−[^4]: To extend the metaphor, stars are a neighborhood to live in -- they're
191− easier for other planets to see, so when they want to send you a message
192− they look for your star first. If they don't even know where your star is,
193− they can certainly find your star's galaxy, and that will be enough to
194− locate the star. Of course, if your star is not providing satisfactory
195− service, you can take your planet and move to another star.
195+<a name="f4" href="#4">[4]</a>: To extend the metaphor, stars are a
196+neighborhood to live in -- they're easier for other planets to see, so when
197+they want to send you a message they look for your star first. If they don't
198+even know where your star is, they can certainly find your star's galaxy, and
199+that will be enough to locate the star. Of course, if your star is not
200+providing satisfactory service, you can take your planet and move to another
201+star.