Updateable Subspace Key (Freenet)

Updeteable Subspace Keys are simply a convenient way to receive the data from Signed Subspace Key (Freenet). One can always transform one key into another.

To turn SSK into a USK one must:
 * 1) Change "SSK@" into "USK@" in the beginning of the key
 * 2) In the data name part change ".+-\d+" (see regex notation) into ".+/\d+"

USKs differ in that they will update the version number when a newer version is known. If one wants to request that the node first looks for a newer version even if it is not yet known, then a symbol '-' needs to be added to the number (making a number negative).
 * For example: USK@..../mysite/5/ will load the fifth version of the site unless a newer version is known; while USK@..../mysite/-5/ will first search the network for version 6, 7, ... and then display the last one found.

USK is the preferred way to link to files in Freenet 0.7.

External link
https://wiki.freenetproject.org/Updateable_Subspace_Key