Note that it does not prevent storing p2p access tokens or multicast
encryption keys, since those are not cached; the previous commit
established the distinction.
How well this works depends on how often getRemoteCredPair is called and
how expensive it is. In some cases setting this will result in an annoying
number of gpg password prompts and/or slowdowns due to reading creds
from the git-annex branch and decrypting, which could be improved by calling
getRemoteCredPair less often.
This commit was sponsored by Ilya Shlyakhter on Patreon.
In particular, specifying multiple keyid= in enableremote/initremote
doesn't work, and never has AFAICS, so don't suggest using it.
Also, there was some public/private key wording confusion.
This is useful for makking a special remote that anyone with a clone of the
repo and your public keys can upload files to, but only you can decrypt the
files stored in it.
With the initremote parameters "encryption=pubkey keyid=788A3F4C".
/!\ Adding or removing a key has NO effect on files that have already
been copied to the remote. Hence using keyid+= and keyid-= with such
remotes should be used with care, and make little sense unless the point
is to replace a (sub-)key by another. /!\
Also, a test case has been added to ensure that the cipher and file
contents are encrypted as specified by the chosen encryption scheme.
/!\ It is to be noted that revoking a key does NOT necessarily prevent
the owner of its private part from accessing data on the remote /!\
The only sound use of `keyid-=` is probably to replace a (sub-)key by
another, where the private part of both is owned by the same
person/entity:
git annex enableremote myremote keyid-=2512E3C7 keyid+=788A3F4C
Reference: http://git-annex.branchable.com/bugs/Using_a_revoked_GPG_key/
* Other change introduced by this patch:
New keys now need to be added with option `keyid+=`, and the scheme
specified (upon initremote only) with `encryption=`. The motivation for
this change is to open for new schemes, e.g., strict asymmetric
encryption.
git annex initremote myremote encryption=hybrid keyid=2512E3C7
git annex enableremote myremote keyid+=788A3F4C
This option avoids gpg key distribution, at the expense of flexability, and
with the requirement that all clones of the git repository be equally
trusted.
