cyberspace← Learn · identity
Your key is your coordinate
A Nostr public key is a 256-bit number. Cyberspace reads that number as a place: 85 bits of X, 85 of Y, 85 of Z and one plane bit, laid down in the order the specification fixes. Paste any key, or your own npub, and watch it land.
The layout
The 256 bits are not three numbers laid end to end. They are interleaved: bit 0 is the plane, and above it the bits go Z, Y, X, Z, Y, X, so that bit 255 is the top bit of X, bit 254 the top bit of Y and bit 253 the top bit of Z (section 2.2). Read the key from the left and it spells X Y Z X Y Z … P. The strip under the scene colors each bit by the axis it belongs to, and the three rows below it are the same bits gathered up: every third one.
Interleaving is not a packing trick. It puts the high bits of all three axes first, so two coordinates that are close in space share a long common prefix, and a long common prefix means they fall inside the same aligned subtrees (section 4.5). That is the property everything else stands on: movement cost, region keys and discovery all start from which aligned block a coordinate is in.
Identity is location
You do not choose where you spawn. The key chooses (section 3.1). A spawn event's coordinate MUST equal its public key (section 3.2), so there is no registry of who is where and no authority that assigns places: anyone who knows a key knows its spawn point, and a different place needs a different identity.
Where keys land
A fresh key is 256 random bits, so it lands anywhere in a cube about 4.5 trillion kilometers on a side (section 9.2). Earth sits at the exact center, 284 on every axis, and its surface is 6,378 km out (section 9.7). Press Random key and the readout will usually say the key is around a trillion kilometers from Earth: a tenth of a light-year. Almost all of cyberspace is empty space, and almost every identity is born in it.
The presets include the six golden vectors of section 9.8: keys that would spawn on Earth's surface at named latitudes and longitudes. Their hex begins e000… or c492…, and the bit strip shows why. Being within a few thousand kilometers of 284 on every axis means bit 84 of each axis is set and the bits just under it are nearly all one or nearly all zero, and after interleaving those become the repeating 492492 pattern: one axis a hair below 284. London and New York both show it on Z, because both are west of the prime meridian.
The sector tags
Every event that claims a coordinate MUST carry four tags: X, Y and Z, each axis value shifted right by 30 bits, and S, the three joined with dashes (section 10). A sector is a cube of 230 Gibsons, about 12.5 cm, and its index is a 55-bit number, which is why the readout's sector values are so long. The tags exist so a relay can answer "what is in this sector" or "what is in this slab along X" without understanding the coordinate at all.
Two planes
The plane bit selects dataspace, which maps to Earth, or ideaspace, which maps to nothing (section 2.4). Both planes share the same X, Y and Z and the same mathematics; only the physical meaning differs. The scene draws a dataspace key in cyan and an ideaspace key in magenta, and the last readout line says what, if anything, the numbers mean on Earth.