47 lines
1.9 KiB
Plaintext
47 lines
1.9 KiB
Plaintext
Encrypted files
|
|
---------------
|
|
|
|
- Each encrypted file has at least two components: the encrypted data file
|
|
('catfile'), and it's corresponding key file ('keyfile'). Shared files have an
|
|
additional key file ('share key'). The catfile contains the encrypted data
|
|
concatenated with delimiter text, followed by the initialisation vector ('IV'),
|
|
and padding. e.g.:
|
|
|
|
[encrypted data string][delimiter][IV][padding]
|
|
[anhAAjAmcGXqj1X9g==][00iv00][MSHU5N5gECP7aAg7][xx] (square braces added)
|
|
|
|
- Directory structure:
|
|
- Encrypted user data (catfiles) are stored in the usual /data/user/files dir
|
|
- Keyfiles are stored in /data/user/files_encryption/keyfiles
|
|
- Sharekey are stored in /data/user/files_encryption/share-files
|
|
|
|
- File extensions:
|
|
- Catfiles have keep the file extension of the original file, pre-encryption
|
|
- Keyfiles use .keyfile
|
|
- Sharekeys have .shareKey
|
|
|
|
Shared files
|
|
------------
|
|
|
|
Shared files have a centrally stored catfile and keyfile, and one sharekey for
|
|
each user that shares it.
|
|
|
|
When sharing is used, a different encryption method is used to encrypt the
|
|
keyfile (openssl_seal). Although shared files have a keyfile, its contents
|
|
use a different format therefore.
|
|
|
|
Each time a shared file is edited or deleted, all sharekeys for users sharing
|
|
that file must have their sharekeys changed also. The keyfile and catfile
|
|
however need only changing in the owners files, as there is only one copy of
|
|
these.
|
|
|
|
Notes
|
|
-----
|
|
|
|
- The user passphrase is required in order to set up or upgrade the app. New
|
|
keypair generation, and the re-encryption of legacy encrypted files requires
|
|
it. Therefore an appinfo/update.php script cannot be used, and upgrade logic
|
|
is handled in the login hook listener. Therefore each time the user logs in
|
|
their files are scanned to detect unencrypted and legacy encrypted files, and
|
|
they are (re)encrypted as necessary. This may present a performance issue; we
|
|
need to monitor this. |