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[Gzz-commits] manuscripts/pointers article.rst
From: |
Benja Fallenstein |
Subject: |
[Gzz-commits] manuscripts/pointers article.rst |
Date: |
Mon, 27 Oct 2003 15:58:44 -0500 |
CVSROOT: /cvsroot/gzz
Module name: manuscripts
Branch:
Changes by: Benja Fallenstein <address@hidden> 03/10/27 15:58:44
Modified files:
pointers : article.rst
Log message:
intro mostly there in first draft stage
CVSWeb URLs:
http://savannah.gnu.org/cgi-bin/viewcvs/gzz/manuscripts/pointers/article.rst.diff?tr1=1.28&tr2=1.29&r1=text&r2=text
Patches:
Index: manuscripts/pointers/article.rst
diff -u manuscripts/pointers/article.rst:1.28
manuscripts/pointers/article.rst:1.29
--- manuscripts/pointers/article.rst:1.28 Mon Oct 27 14:41:04 2003
+++ manuscripts/pointers/article.rst Mon Oct 27 15:58:44 2003
@@ -48,7 +48,7 @@
have lost interest.>>>
We don't propose that every byte of information ever published
-on the Web should have to be kept around forever. However,
+on the Web has to be kept around forever. However,
we do believe that as long as someone does keep a copy,
data should remain accessible, and links should continue
to work.
@@ -65,7 +65,7 @@
like cryptographic hashes.
A file identified by a cryptographic hash
can be downloaded from any server that has a copy; the client
-can then check it is the correct file by checking the hash.
+can then check the integrity of the file by checking it against the hash.
.. <<<Self-verifying means that given the identifier and a file,
a client can check that the file matches the identifier.>>>
@@ -78,24 +78,38 @@
is not viable on a global scale:
"[I]f you put information in a name, it decreases its longevity;
if you don't you can't dereference it to a resource."
-However, as we have observed in [fallenstein03storm]_,
-with the advent of
-efficient peer-to-peer lookup mechanisms such as
+
+However, as observed in [fallenstein03storm]_,
+with the advent of efficient peer-to-peer lookup mechanisms such as
distributed hashtables (DHTs), this observation
-is no longer true.
+is no longer true. A DHT is quite able to resolve a
+hash-based identifier on a global scale,
+as evidenced by applications like the Cooperative
+File System (CFS, [dabek01widearea]_) and
+the Overnet file sharing client [overneturl]_.
+
+.. SFR (semantic-free referencing) not all that close,
+ though semantic-free idea shared (SFR takes along
+ many problems of the Web)
-Using DHTs
-to resolve location-independent identifiers on the Web
-has been proposed by Balakrishnan et.al.
-[balakrishnan03semanticfree-andalso-walfish03dns]_.
+.. <<<(Using DHTs
+ to resolve location-independent identifiers on the Web
+ has been proposed by Balakrishnan et.al.
+ [balakrishnan03semanticfree-andalso-walfish03dns]_.
+ However, in their work, the location-independent identifier
+ merely points to a Web server administered by the publisher
+ of a Web page; if the original publisher discontinues
+ maintenance of the page, it would still drop off the Web.)>>>
-.. Proposal: A location-independent Web (closest thing is Freenet (ref))
+ XXX move to related work?
+
+.. Proposal: A location-independent Web <<<(closest thing is Freenet (ref))>>>
We propose, then, to build a location-independent Web
based on self-verifying identifiers.
-The project that is currently closest to this goal is Freenet,
-a XXX
+.. <<<The project that is currently closest to this goal is Freenet,
+ a XXX>>>
.. Benefits of hash-based addressing:
- Pages easily movable between servers
@@ -106,18 +120,26 @@
- Verifiable
- Same namespace for local and for non-local data
-.. SFR (semantic-free referencing) not all that close,
- though semantic-free idea shared (SFR takes along
- many problems of the Web)
+Using hash-based addressing in such a scheme has several benefits:
-.. Other projects exploit some of the advantages of hash-based
+- Pages can be moved between servers without breaking links.
+- Links continue to work as long as *anybody* keeps a copy
+ of their targets, even if the original publisher does not
+ maintain the Web page any longer.
+- Downloaded files can keep their global identifiers.
+ Links between two downloaded Web pages automatically work.
+- It is possible to implement load-balancing schemes in which
+ a user downloads a page from anybody who happens to have a copy.
+- Different networks can be used to download a file. XXX
+
+.. <<<Other projects exploit some of the advantages of hash-based
(storage systems: CFS, PAST; web caching: Squirrel),
- but don't address the Web.
+ but don't address the Web.>>>
-.. The infrastructure behind CFS, PAST and Squirrel: Peer-to-Peer
+.. <<<The infrastructure behind CFS, PAST and Squirrel: Peer-to-Peer>>>
-.. Quite recently, several Peer-to-Peer architectures have been
- proposed that use hash-based, loc.ind. ids
+.. <<<Quite recently, several Peer-to-Peer architectures have been
+ proposed that use hash-based, loc.ind. ids>>>
.. Possibility of desktop integration in ways that the location-dependent
Web cannot archieve, through the novel combination of
@@ -126,14 +148,61 @@
.. However, there's a problem with this: versioning -----
Basic problem: Hash-based addressing allows no updates
+However, a document refered to by a cryptographic hash
+can obviously not be changed (without making it a different document,
+refered to by a different hash). For most Web pages, this is not
+acceptable [#academic-articles-hashlinking]_. In this paper,
+we examine solutions to this problem that keep the desirable properties
+of hash-based addressing.
+
.. Contributions; structure of this paper ----
.. Main contrib: Pointer records for implementing updating
+The main contribution of our paper are *pointer records*.
+A document is identified by a *pointer*, the hash of a
+public key. A pointer record is a file signed by the
+corresponding private key, containing the pointer's identity,
+the hash of a version of that document, and a timestamp.
+The newest version of a document is obtained by searching
+the peer-to-peer network for all pointer records associated
+with this pointer, and picking the newest one.
+
+This scheme is quite close to OceanStore's concept of
+*heartbeats*. However, the difference is that in OceanStore,
+heartbeats are controlled by an inner circle of servers,
+the *primary replica*, chosen by the owner of the document.
+In this scheme, when a document ceases to be maintained
+by its primary replica, it is impossible/becomes harder/*what*?XXX
+to retrieve the newest version of the document.
+
+(XXX IS THIS TRUE?)
+
.. Other contribs:
- The idea of a location-independent Web including
location-independent version management
- Diffs
+ - Permanent signature scheme sketch
+
+In addition to pointer records, this paper XXX
+
+.. Structure of this paper
+
+The remainder of this paper is structured as follows.
+In Section 2, we review related work in version management,
+and find that existing peer-to-peer versioning systems
+do not provide the benefits of hash-based addressing.
+In Section 3, we introduce our fundamental, hash-based data model
+for a location-independent Web. In Section 4, we propose
+a versioning system built on top of this data model.
+In Section 5, we introduce a scheme for storing only
+the differences between versions that works with our
+basic data model, making the storage of past versions
+more economical. In Section 6, we outline solutions
+to the permanency issues raised by the use of
+cryptographic keys (which may be stolen or lost).
+Section 7 concludes.
+
Related work
@@ -305,3 +374,8 @@
.. [#rtg-links] ``http://www.seds.org/spaceviews/cassini/rtgpages.html``.
All links dereferenced on October 27th, 2003.
+.. [#academic-articles-can-use-hashlinking] A notable exception
+ may be academic articles, in which references to other articles
+ are ideally to an immutable version, and in which references
+ are generally not circular, making this domain map neatly
+ to the properties of hash-based referencing.
\ No newline at end of file
- [Gzz-commits] manuscripts/pointers article.rst, (continued)
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Hermanni Hyytiälä, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/27
- [Gzz-commits] manuscripts/pointers article.rst,
Benja Fallenstein <=
- [Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Benja Fallenstein, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/10/29
- [Gzz-commits] manuscripts/pointers article.rst, Tuomas J. Lukka, 2003/10/29