docs: update README.md & SECURITY.md (#143)

* reduce cuprate banner size

* update readme

* update `SECURITY.md

* formatting

* readme: add todo

* update license section

* add user book, current about

* formatting

* formatting

README.md

@@ -1,16 +1,58 @@
-![Cuprate](misc/logo/wordmark/CuprateWordmark.svg)
+<div align="center">
+	<img src="misc/logo/wordmark/CuprateWordmark.svg" width="50%"/>
 
+An alternative Monero node implementation.
 
-----
-
-> An up and coming Rust Monero node.
+_(work-in-progress)_
 
 [![Matrix](https://img.shields.io/badge/Matrix-Cuprate-white?logo=matrix&labelColor=grey&logoColor=white)](https://matrix.to/#/#cuprate:monero.social) [![CI](https://github.com/Cuprate/cuprate/actions/workflows/ci.yml/badge.svg)](https://github.com/Cuprate/cuprate/actions/workflows/ci.yml)
 
-Cuprate will be an alternative Monero node written from the ground up in Rust. It 
-will be able to independently validate Monero consensus rules providing a layer of 
-security and redundancy for the Monero network.
+</div>
+
+## Contents
+- [About](#about)
+- [Documentation](#documentation)
+- [Contributing](#contributing)
+- [Security](#security)
+- [License](#license)
+
+<!--
+TODO: add these sections someday.
+- [Status](#status) // when we're near v1.0.0
+- [Getting help](#getting-help) // issue tracker, user book, matrix channels, etc
+- [Build](#build)
+	- [Windows](#windows)
+	- [macOS](#macOS)
+	- [Linux](#Linux)
+-->
+
+## About
+Cuprate is an effort to create an alternative [Monero](https://getmonero.org) node implementation in [Rust](http://rust-lang.org).
+
+It will be able to independently validate Monero consensus rules, providing a layer of security and redundancy for the Monero network.
+
+<!-- TODO: add some details about what Cuprate is and is not, goals, status -->
+
+## Documentation
+_Cuprate is currently a work-in-progress; documentation will be changing/unfinished._
+
+Cuprate maintains various documentation books:
+
+| Book                                                            | Description                                                |
+|-----------------------------------------------------------------|------------------------------------------------------------|
+| [Cuprate's architecture book](https://architecture.cuprate.org) | Documents Cuprate's internal architecture & implementation |
+| [Cuprate's protocol book](https://monero-book.cuprate.org)      | Documents the Monero protocol                              |
+| [Cuprate's user book](https://user.cuprate.org)                 | Practical user-guide for using `cuprated`                  |
+
+For crate (library) documentation, see the `Documentation` section in [`CONTRIBUTING.md`](CONTRIBUTING.md).
+
+## Contributing
+See [`CONTRIBUTING.md`](CONTRIBUTING.md).
+
+## Security
+Cuprate has a responsible vulnerability disclosure policy, see [`SECURITY.md`](SECURITY.md).
+
+## License
+The `binaries/` directory is licensed under AGPL-3.0, everything else is licensed under MIT.
 
-Cuprate will help to protect the network from implementation bugs that could 
-cause a variety of issues, plus because it's written in a memory safe language Cuprate 
-will be less likely to suffer from memory safety issues compared to monerod.
+See [`LICENSE`](LICENSE) for more details.

SECURITY.md

@@ -1,11 +1,15 @@
 # Security Policy
 
-## Supported Versions
+## Reporting a vulnerability
+If you have discovered a vulnerability within Cuprate, please do not open a GitHub issue or announce it publicly.
 
-We only support the latest version available as it follows monero specifications and older client is therefore prohibited by the network.
+Please contact us directly by email using our PGP keys in the [`gpg_keys/`](misc/gpg_keys/) directory or via an encrypted Matrix channel.
 
-## Reporting a Vulnerability
+Thanks for being quiet.
 
-If you ever discover a vulnerability, please do not open a github issue. Contact us by mail directly using our pgp keys under the gpg_keys folder in the repository. We're also available on Matrix.
-You can also alert us using the *Report a Vulnerability* feature of Github. Thanks for being quiet. We'll always disclose the vulnerability after patching it and encourage everyone to fetch the
-security update.
+## Contact
+Please disclose vulnerabilities to one of the trusted maintainers below:
+
+| Trusted maintainer | PGP key | Email address | Matrix ID |
+|--------------------|---------|---------------|-----------|
+| [Boog900](https://github.com/Boog900) | [`boog900.asc`](misc/gpg_keys/boog900.asc) | `boog900@tutanota.com` | `@boog900:monero.social`