Date: Wed, 14 Jan 2015 21:27:20 +0300 From: rozhuk.im@gmail.com To: "'Gleb Kurtsou'" <gleb@freebsd.org> Cc: 'Kimmo Paasiala' <kpaasial@gmail.com>, freebsd-geom@freebsd.org, 'Adam Nowacki' <nowakpl@platinum.linux.pl>, 'FreeBSD Hackers' <freebsd-hackers@freebsd.org> Subject: RE: ChaCha8/12/20 and GEOM ELI tests Message-ID: <54b6b50a.d17b700a.5b19.4bd3@mx.google.com> In-Reply-To: <20150114084457.GA4099@reks> References: <54b33bfa.e31b980a.3e5d.ffffc823@mx.google.com> <54B4AE55.9090205@platinum.linux.pl> <54b5d299.4914980a.61cd.43a6@mx.google.com> <CA%2B7WWScVQ9LwQQ3NR8ipkdxroqdg26Q2dB__%2B2wRr_0kPmJODQ@mail.gmail.com> <CA%2B7WWSf%2B7N6foTKxarANfwgAitQXfxt%2B_e-HgcokzU5cVparAA@mail.gmail.com> <54b5fbbe.4457700a.2456.6944@mx.google.com> <20150114084457.GA4099@reks>
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> > > >> Depends on the capabilities of the attacker. > > > >> > > > >> To be able to continuously read encrypted sectors for data > > > collection is too much. > > > >> > > > > > > > When talking about disk encryption the first assumption is that > > > the attacker always has this capability, even with so much power > > > the attacker shouldn't be able to break the encryption scheme. If > > > he > can > > > then the encryption scheme is not secure. > > > > > > Ift the attacker can learn anything about the unencrypted data or > > > predict something about future encrypted or unencrypted blocks by > > > analyzing the previous encrypted blocks the encryption scheme > should > > > be considered insecure. > > > > I consider the case when the disk can be obtained by physically an > attacker. > > All the rest of the disk directly connected to the computer. > > Do you imply that scheme you propose will not provide support for > network storage? What about HAST, iSCSI, ATA over Ethernet, Cinder or > whatever else is fancy those days? > > Documenting such limitation would make geli look terrible, not to > mention confusing.. Provide, but insecure / less secure. :) > > If an attacker can read encrypted data directly to disk means that > the > > system is already compromised by an attacker, > > Unless you don't have knowledge of attacker possessing such power :) God knows everything :) How to protect your data from God? :) > I would happily throw my encrypted disk away every time I find out it > was tempered with offline. The good thing I never know whether is has > happened (good way to save some money as well). > > That is why assumption that attacker has access to encrypted disk > should hold. ChaCha does not suit you. > In case of block device encryption overall situation is much worse. > Imagine you find out that your geli keys were compromised. There is no > mechanism provided to switch to new encryption key while retaining > access to old data and changing key for new data without creating full > copy. Technically, you can change the encryption keys geli without creating a complete copy, but if something happens in the process there is a risk of losing some data. I think that's why it did not implement.
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