EMCA: yet another ACME client (v0.2.0)
======================================

About
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This is emca [1], yet another client for the ACME protocol used by the Let's
Encrypt project.  The code is based on acme-tiny [2], and attempts to be even
easier to audit, hack and maintain.

[1] <https://gitea.com/CasperVector/emca>.
[2] <https://github.com/diafygi/acme-tiny>.


Usage
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To run this client, you need Python (either 2.x or 3.x), OpenSSL (the binary
executable file) and a working HTTP daemon.  Also modify the variables in
`emca.conf' to suit your needs.  Additionally, it is strongly recommended to
read the source code (less than 200 lines and carefully organised) of `emca.py'
by yourself to make sure you trust it.

Generate the keys, and place them in suitable locations with appropriate
filenames (note that the server key should be only readable by the HTTP daemon,
not the ACME client program; the ACME account key should be only readable by the
ACME client program; the CSR can be globally readable, but should only be
writable by the system administrator):

$ openssl genrsa 4096 > emca.key; openssl genrsa 4096 > server.key
$ openssl req -new -sha512 -key server.key -subj '/CN=example.com' > server.csr

To issue and renew your certificate (should be done at least once every 90
days; 1 month recommended to avoid hitting the rate limit on the ACME server),
make sure the ACME challenge directory is writable by the ACME client program
and enter-able (i.e. with the `x' permission flag enabled) by the HTTP daemon,
and the current umask allows other users to read files created by the ACME
client program; then run:

$ ./emca.py emca.conf > server.crt

It is recommended to create a dedicated non-privileged user for running the
ACME client, and only provision the ACME challenge directory temporarily (using
some automation) when the ACME client is scheduled to run.


Copying
-------

Copyright (c) 2015 Daniel Roesler
Copyright (c) 2015-2017,2021 Casper Ti. Vector

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.