add Security+Hashing sections to README.md

README.md

@@ -2,7 +2,7 @@
 ### Philosophy
 > [!TODO] My philosophy has kinda changed since the beginning
 
-###### Repo Structure
+### Repo Structure
 Modules are organised into groups (ie "Core"), from here a module is structured as either:
 1. a single `.nix` file (ie bluetooth.nix). I do this when I won't implement an alternative
 2. a directory (ie `sound`) containing a set of alternative implementations and a `default.nix` 
@@ -10,6 +10,11 @@ that simply imports one of the implementations. For the `sound` example I curren
 to default to `pipewire.nix`. I haven't made alternatives yet but the idea is that it is HIGHLY likely
 I do in future.
 
+### Security Considerations
+###### Hashing
+For services where password hashing is done infrequently (ie my forgejo instance with signups disabled)
+use argon2 (argon2id) with default `argon2$2$65536$8$50` (typically). Otherwise bcrypt is preferred.
+
 ### TODO
 There are a lot of commented `# TODO: ...` items in this repository.
 All (most) of my commented directives can be found via this pattern: