Fossil

This document tries to bring closer a more ubiquitous,
seamless and useful signing and verification of artifacts.

**This is a draft!**  
It is incomplete.
It sketches out a few possible solutions
that try to balance flexibility and complexity.
It sketches out a few possible solutions.
These solutions try to balance flexibility and complexity.

<a id="toc"></a>
Table of content:

 * [Agenda and context](#context)
 * [Identity model](#identity)
 * [Auxiliary definitions](#defs)

> in some prominent (yet undecided) format...

[data in transit]: https://en.wikipedia.org/wiki/Data_in_transit
[data at rest]: https://en.wikipedia.org/wiki/Data_at_rest
[TLS]: https://en.wikipedia.org/wiki/Transport_Layer_Security
[CA]: https://en.wikipedia.org/wiki/Certificate_authority
[cold wallets]: https://en.wikipedia.org/wiki/Cold_wallet
[struct]: (/doc/2022-05-28/www/fileformat.wiki#structural)
[struct]: /doc/2022-05-28/www/fileformat.wiki#structural

<a id="identity"></a>
Identity model
==============

**Identity** is a cryptographically sound avatar of a human being.
[Identity is distinguished by the public key of it's **main keypair**]

In both cases a [human-friendly variant of base32 encoding][^base32]
is used in order to prevent confusion with artifacts' UUIDs and also to
facilitate verbal transfers (in the context of signing parties and alike).

Identity does not expire, but can be explicitly **abrogated**.
Identity's *main key* may be used to claim that it was *compromised*
or [intentionally *destroyed*.][^indestroy]
Also identity's *main key* may be used to declare a **trusted revoker** —
Also identity's *main key* may be used to declare a [**trusted revoker**][^revoker] —
a public key that is authorized to claim that identity's *main key*
is *lost*, *destroyed* or *compromised*.
The former claim may be recovered using the identity's *main key*, while
in the later two cases the whole identity is permanently *abrogated*.
A *trusted revoker* may be a key that is under exclusive control of
identity's owner or may be a *main key* of some other identity.
In both cases authorization of the *trusted revoker* may have an expiration

    * honesty:  
      — intolerance to the falsity of one's own propositions;
        one's own *claims* in particular.

    The integer values of 0, ±1, ±2 and ±3 may be interpreted as
    "same", "slightly", "noticeably" and "much" respectively.

A *claim* with proposition about *trustworthiness* is propogated to all
A *claim* with proposition about *trustworthiness* will be referred to as
**t-claim**. *T-claim* is propagated to all
projects that are relevant for both the *source* and the *destination*.
*T-claims* form a global "social graph".

A *claim* with propositions about *connectedness* and *integrity*
will be referred to as **ci-claim**.
is propagated to all projects that 
*CI-claim* is propagated to all projects that 

 * are relevant for both ends of the *claim*, and that
 * belong to the corresponding *workspace*
   (the one which propositions are about).

For a given signed artifact it is possible to estimate its *legitimacy*
provided that "social graph" contains a path from the identity who makes
an inquiry to the identity who signed that artifact.  
*To be continued...*
Probability that a signed artifact is *legitimate* may be computed for
arbitrary moment of time as weighted average of approximated *integrities*
from the available *ci-claim*s.  
The aforementioned weights are derived from the *t-claims*
using a computation over the underlying "social graph". This computation
starts from the identity who makes an *inquiry* and computes weights of
other identities in a [BFS-like][^BFS] manner, until the author of the
artifact is reached.

<a id="footnotes"></a>
Footnotes
=========

[^base32]:
  Something like [Crockford's Base32
  encoding](https://en.wikipedia.org/wiki/Base32#Crockford.27s_Base32).

[^revoker]:
  It's yet unclear which word is more appropriate: "trusted" or "designated".

[^indestroy]:
  This is a bit speculative because the signing of the
  "intentionally destroyed" *claim* has to precede
  the actual destruction of the last copy of a secret key;
  and that actual destruction may fail silently.

[^Binary]:

  "both directions" through the network of retransmitters
  (not all of which are necessarily participants of a project).

[^when]:
  The exact values of that delay is debatable. It is assumed that two *ERL*s
  might be enough for the *destination* to react on impersonation,
  and five *ERL*s might be enough for reaction from a *trusted revoker*
  or other participants of the *workspace*.
  or other participants of the *workspace*.  
  If the delay is modeled by [Erlang-2 distribution][ErlangK],
  then two *ERL*s give 91% probability that response has been received.

[^BFS]:
  [Breadth-first search](https://en.wikipedia.org/wiki/Breadth-first_search).
  Proceeds like an expanding concentric wave on the water.

[ErlangK]: https://en.wikipedia.org/wiki/Erlang_distribution#Erlang-k