diff --git a/doc/README.mdwn b/doc/README.mdwn
index 0a32efc..455741f 100644
--- a/doc/README.mdwn
+++ b/doc/README.mdwn
@@ -1,7 +1,8 @@
 This is a configuration management system using Haskell and Git.
 
-Propellor enures that the system it's run against satisfies a list of
-properties, taking action as necessary when a property is not yet met.
+[Propellor](https://propellor.branchable.com/) enures that the system it's
+run against satisfies a list of properties, taking action as necessary when
+a property is not yet met.
 
 Propellor is configured via a git repository, which typically lives
 in ~/.propellor/. The git repository contains a config.hs file,
@@ -53,45 +54,6 @@ easy to adapt to a system's special needs.
    hosts.
 10. Write some neat new properties and send patches to <propellor@joeyh.name>!
 
-## security
-
-Propellor's security model is that the hosts it's used to deploy are
-untrusted, and that the central git repository server is untrusted too.
-
-The only trusted machine is the laptop where you run `propellor --spin`
-to connect to a remote host. And that one only because you have a ssh key
-or login password to the host.
-
-Since the hosts propellor deploys are not trusted by the central git
-repository, they have to use git:// or http:// to pull from the central
-git repository, rather than ssh://. 
-
-So, to avoid a MITM attack, propellor checks that any commit it fetches
-from origin is gpg signed by a trusted gpg key, and refuses to deploy it
-otherwise.
-
-That is only done when privdata/keyring.gpg exists. To set it up:
-
-	gpg --gen-key             # only if you don't already have a gpg key
-	propellor --add-key $MYKEYID
-
-In order to be secure from the beginning, when `propellor --spin` is used
-to bootstrap propellor on a new host, it transfers the local git repositry
-to the remote host over ssh. After that, the remote host knows the
-gpg key, and will use it to verify git fetches.
-
-Since the propoellor git repository is public, you can't store
-in cleartext private data such as passwords, ssh private keys, etc.
-
-Instead, `propellor --spin $host` looks for a
-`~/.propellor/privdata/$host.gpg` file and if found decrypts it and sends
-it to the remote host using ssh. This lets a remote host know its own
-private data, without seeing all the rest.
-
-To securely store private data, use: `propellor --set $host $field`
-The field name will be something like 'Password "root"'; see PrivData.hs
-for available fields.
-
 ## debugging
 
 Set `PROPELLOR_DEBUG=1` to make propellor print out all the commands it runs