[p2p-hackers] "generic & secure" DHT table implementation?

[Ivan Shmakov]

    Abstract

	There're (several?) BitTorrent-specific DHT's, and the P2P
	anonymity protocols (such as GNUnet) seem to (effectively)
	implement their own DHT's.  But is there any kind of a
	buniversalb (i. e., transport protocol-independent) DHT?  And if
	not, why?


    Searching by content-derived identifiers

	There're currently a number of P2P-friendly content-derived
	resource identifiers, such as the BitTorrent binfohashb values
	(which can be embedded within magnet: schema URI's, like [1]),
	as well as the URI's used in GNUnet and Freenet frameworks (like
	[2]), both non-standard (and the GNUnet ones are, as it seems,
	interpreting the base URI specification in somewhat an odd way.)

	What seems to be missing, however, is a bgenericb DHT network
	that could be used to search both the relevant metadata (such as
	.torrent or Metalink files), and the peers participating in a
	particular data exchange (and the respective protocols they
	support), using one or more of an extensible set of identifiers
	(including BitTorrent infohashes, GNUnet URI's, and the plain
	SHA-1, SHA-2, or SHA-3 values.)


    How's it useful?

	With such a DHT, Alice, having only a bandwidth-limited Internet
	connection, could compute a SHA-256 of a large file on her host,
	and send the former to Bob, which, in turn, would use any
	downloading software (implementing the support for the
	aforementioned bgenericb DHT) to discover the possible sources
	for the file in question and retrieve it.


    Security issues

	As for the security, the brecordsb in such a table could be
	digitally signed, with the set of the btrustedb public keys
	being comprised of those keys explicitly approved by the user,
	the public keys of the peers with which a successful data
	exchange has occurred before, and the public keys trusted by the
	peers already trusted, up to a certain depth.  (There could then
	be different levels of trust, just like, e. g., in GnuPG, and
	perhaps other OpenPGP software.)

	The purpose of such a facility is exactly to allow for the use
	of (non-piecewise) digest to metadata records, which otherwise
	could easily be spoofed, and used to force the downloader to
	spend its resources to download an otherwise irrelevant data.


    The question

	The question is: are there any designs, either implemented, or
	described in detail, allowing for operation as described above,
	or are there specific reasons for which the outline above is not
	feasible to implement?

	TIA.

[1] magnet:?xt=urn:btih:fb5c0d7946469ba48121607458e360cb31336e55
[2] gnunet://ecrs/chk/9E4MDN4VULE8KJG6U1C8FKH5HA8C5CHSJTILRTTPGK8MJ6VHORERHE68JU8Q0FDTOH1DGLUJ3NLE99N0ML0N9PIBAGKG7MNPBTT6UKG.1I823C58O3LKS24LLI9KB384LH82LGF9GUQRJHACCUINSCQH36SI4NF88CMAET3T3BHI93D4S0M5CC6MVDL1K8GFKVBN69Q6T307U6O.17992

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