Full Disclosure mailing list archives
Re: [PAPER] Juggling with packets: floating data storage
From: Nicholas Weaver <nweaver () CS berkeley edu>
Date: Wed, 8 Oct 2003 12:47:17 -0700
On Wed, Oct 08, 2003 at 08:18:12PM +0200, Michal Zalewski composed:
The higher level juggling is still pointless. Lets assume I still have the 1 Gb link to the outside world, and the data round trip latency is a minute (the amount of time data can be stored externally before it comes back to me). Thats still just 60 Gb of data, or 7.5 GB. And I'm having to burn a 1 Gb link to do it!Should you actually read the paper, it would be easier to comprehend the idea. The paper proposes several approaches that do not require you to send the data back and forth all the time; in some cases, you can achieve near-infinite latency with a very low "sustaining traffic" necessary to prevent the data from being discarded. Besides, the storage size is not the main point, the entire approach is much more interesting from the limited deniability high-privacy storage point of view.
You have some refresh time required, just like DRAM or any other lossy/decaying medium. Without the refresh, you will have uncorrectible data decay. Its simply the refresh bandwidth and refresh rate. So lets assume a 1 DAY refresh time, and a 1 Gb refresh bandwidth. That's still a maximum of ~10 TB of storage (3600 * 24 / 8), and you are going to have to be saturating the link to maintain it. With a 100 Mb refresh bandwidth, thats 1 TB. I can go out and buy a box which holds nearly 1 TB for <$2000. Heck, I can buy a >2 TB RAID array, FROM APPLE (hardly a low price vendor) for $11k! In terms of serving data, CDN's reportedly charge around $20/GB served or so, or you can always construct a BitTorrent-like network to use the edge-hosts, which is what Valve wants to do for selling/patching HalfLife. Even given a low/moderate-user (~100 user) network, the data cost is going to be pretty extreem to maintain refresh, and as a result, rather/very unstealthy. Lets assume 1 TB shared between 1k users, and a 1 hour refresh time (probably still way high). Thats still 200 Kb/s/user continuous bandwidth. I don't know about you, but I can't get that reliably on my cable modem upload, and if I DID use that much bandwidth, ALL THE TIME, the cable company would probably come knocking. Why not just build a distributed filesystem for those 1K users? The only real advantage is a monocrum of stealth, but it isn't really stealthy if you are storing a non-trivial amount of data: the network traffic is "Storage volume / refresh time", and the refresh time is going to have to be fairly short to have a monocrum of reliability. Burning even just 10Kb/s/user isn't going to be "stealthy" in practice, due to the continual load. For storing a small quantity of data (eg, ~1-2 GB or less), there are much better covert repositories one could consider.
The second observation is that not all the data has to be send back and forth all the time. Interesting.
The refresh rate is required for parasitic storages, to prevent data decay and to recompute checksums etc to handle data loss. Even given a 1 WEEK refresh cycle, a 100 Mb continual refresh bandwidth only gets you 7 TB of storage, 1 Gb aggregate bandwidth gets 70 TB. -- Nicholas C. Weaver nweaver () cs berkeley edu _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html
Current thread:
- [PAPER] Juggling with packets: floating data storage Wojciech Purczynski (Oct 06)
- Re: [PAPER] Juggling with packets: floating data storage S G Masood (Oct 06)
- Re: [PAPER] Juggling with packets: floating data storage petard (Oct 06)
- RE: [PAPER] Juggling with packets: floating data storage Alun Jones (Oct 08)
- Re: RE: [PAPER] Juggling with packets: floating data storage Michal Zalewski (Oct 08)
- Message not available
- Re: [PAPER] Juggling with packets: floating data storage Nicholas Weaver (Oct 08)
- Re: [PAPER] Juggling with packets: floating data storage Michal Zalewski (Oct 08)
- Re: [PAPER] Juggling with packets: floating data storage Nicholas Weaver (Oct 08)
- Re: [PAPER] Juggling with packets: floating data storage Michal Zalewski (Oct 08)
- Internet Explorer (BAN IT !!!) Stephen (Oct 08)
- RE: Internet Explorer (BAN IT !!!) Brent Colflesh (Oct 08)
- Re: Internet Explorer (BAN IT !!!) gregh (Oct 08)
- Re: Internet Explorer (BAN IT !!!) Paul Schmehl (Oct 08)
- Re: Internet Explorer (BAN IT !!!) Irwan Hadi (Oct 08)
- Re: Internet Explorer (BAN IT !!!) Peter King (Oct 09)
- Re: Internet Explorer (BAN IT !!!) jelmer (Oct 09)
- Re: Internet Explorer (BAN IT !!!) John Sage (Oct 09)
- Re: [PAPER] Juggling with packets: floating data storage Nicholas Weaver (Oct 08)
- Re: Internet Explorer (BAN IT !!!) gregh (Oct 09)