mirror of
https://github.com/moparisthebest/open-keychain
synced 2024-12-26 00:48:51 -05:00
56 lines
2.3 KiB
Markdown
56 lines
2.3 KiB
Markdown
# Design Notes on Open-Keychain
|
|
|
|
This document contains notes on the software design of open keychain. Points
|
|
with a * are yet to be implemented.
|
|
|
|
|
|
## Database design
|
|
|
|
The database has two distinct types of tables:
|
|
- The key\_ring\_{public,secret} tables, which hold binary blobs of all known
|
|
public and private keys, respectively, and nothing else.
|
|
- All other tables, which cache information about key rings in a consistent
|
|
manner. This information includes various pieces of metadata about each key's
|
|
subkeys, user ids, and certificates.
|
|
|
|
### Constraints
|
|
|
|
All tables in the database have FOREIGN KEY constraints related to the
|
|
key\_ring\_public table. This is also true for the key\_ring\_secret table,
|
|
which means that secret keys cannot exist in the database without their public
|
|
key counterparts. This has implications in particular on the order of insertion
|
|
for private key rings and their public key ring counterparts into the database,
|
|
even more so when editing a key ring is edited.
|
|
|
|
### Cache usage considerations
|
|
|
|
It is of note that extraction of metadata from key rings is in some cases a
|
|
surprisingly expensive operation. As a prime example (heh), properly extracting
|
|
a key's associated primary user id requires examination and possibly
|
|
verification of all self-certificates, which in turn requires examination of
|
|
all certificates.
|
|
|
|
To ensure consistency, each type of metadata must be extracted one way in
|
|
exactly one routine. For this reason, it is often desirable to make use of
|
|
cached data even when the underlying pgp key ring objects are contextually
|
|
available.
|
|
|
|
|
|
## Further work / WIP
|
|
|
|
### Separation of concerns
|
|
|
|
Roughly speaking, the crypto code should be strictly separated from the android
|
|
code. At the time of this writing (30.04.14), most of these thoughts are yet to
|
|
be put into practice.
|
|
|
|
There are three aspects to OK which should be kept largely separate:
|
|
- Firstly, there is Code dealing with pgp and crypto. This code exclusively makes
|
|
use of the BouncyCastle library. It lives in the .pgp package.
|
|
- Secondly, there is code dealing with user interface and system integration,
|
|
which makes exclusive use of Android classes.
|
|
- Between these, there is glue code that is responsible for mapping pgp objects
|
|
to the database, and calling methods provided by the crypto code from the ui
|
|
code.
|
|
|