The Register

This is the Incorrigible Register, kept rather than described. Every article below is sealed with a cipher computed from the article itself and from the seal of the page sealed before it, so that no page can be altered without falsifying every seal that follows. The order is the order in which the entries were written, which is the only order a chain of this kind admits.

The first page is chained to a line copied from that morning’s newspaper, which proves the work was not begun earlier and back-dated:

The Morning Intelligencer, Saturday, 17 April 1847. Board of Trade on brink of second revision of the standard yard.
5645be00f1eb14b9f8c6be1698f0aa82429deaa468c7670ac046fbd3bda968b0

A seal counts only if it falls below a target, and is found by trying numbers until one answers – the number that answered is the nonce. The requirement was raised at the fiftieth entry, the work having become too easy. The fiftieth entry is The Radian Dyke, which had nothing to do with it. Sealing the 180 pages below took 2,623,853 attempts.

The Society described the requirement as a number of leading noughts, and recorded the raise as a move from three noughts to four. That is a folk account of it. A target is a number, and is set here as a proportion of the whole: the seal, read as a number, must fall below one part in sixteen thousand three hundred and eighty-four. Some seals that satisfy it show three noughts and some show four, and both are below the same target. Counting noughts can only ever raise the work sixteenfold at a step; a proportion may be tightened by any amount one likes, which is why the requirement can be raised at all.

On the sealing

Each entry above is sealed by hashing a short header – the seal of the page before it, a digest of the article itself, and a nonce – twice over with SHA-256, and trying nonces until the result falls below the target. Alter any article and its digest changes, so its seal changes, so every seal after it changes: the property the Register was built to have, and the one that ruined it. The scheme is Calvert Cyphrant’s, unchanged in principle since 1847, and it is kept here in the same form he devised.

What it proves is that the encyclopedia is internally consistent at this printing, and nothing further. The seals are recomputed from the articles on every build; anyone may recompute them, which is the intention. But a register of this kind is secured by the number of independent keepers holding copies of it, and this one has one keeper.

Its compiler foresaw the difficulty in every particular except this one, and it is recorded against him at some length. See Calvert Cyphrant, who ended as a quorum of one, which the Register accepted.