At 9:47 AM -0800 1/29/98, Jim Gillogly wrote:

BTW, I went to look this up in the Cyphernomicon (I sorta think it's reffed in there), but the first 4 sites I saw on Altavista were all dead-end broken links. The Web's ripping... what's the current Preferred URL?

I have no idea. Sometimes I find a site has it, sometimes not. (I'm not interested in keeping my tens of megs of postings on a Web page. Sosumi.) The issue of "URL decay" is a very serious one, affecting directly the use of the Web for footnote citations, legal citations, references, etc. Scientific or academic articles cannot reliably cite URLs, as they are likely to decay or vanish or become corrupted over a matter of months, let alone the years or decades that a technical or academic paper is expected to last and be read. Call it an archivist's nightmare. A couple of years ago I floated an idea out to a handful of Bay Area friends and Cypherpunks, about an idea for an "Eternity.com" service which would act as a kind of "vanity press" for authors, professors, researchers, etc., who wanted to know that a document and URL would have a long persistence, possibly an indefinite persistence. (At the time I used the "Eternity" name I was not consciously aware of Ross Anderson's work on his "Eternity" system, though I may have inadvertently been inspired by his name, which I may have heard on the list or elsewhere. My notion was a bit different from either his Eternity system or any of the recent variants, but the name was based on the same idea of perpetual storage. However, unlike my BlackNet idea, this particular "Eternity" was not focussed on contraband, illegal, controversial, or black market information being distributed and preserved. In fact, the expected customers were mundane academics and corporate users...or vanity users...anyone, basically, who wanted to know that a paper or document of theirs could be reliably cited by others and that the citations would not exhibit the "URL decay" so commonly seen today.) Like I said, I sent this to a handful of Bay Area friends and Cypherpunks, mainly to see if they had any comments or interest. I chose at that time not to send my idea out to the Cypherpunks list, as I had some thoughts about maybe trying to commercialize the idea.... However, I haven't, so I may as well send this idea along. Here is the piece I sent out in late '95: Return-Path: tcmay@got.net Received: from [205.199.118.202] (tcmay.got.net [205.199.118.202]) by you.got.net (8.6.9/8.6.9) with SMTP id OAA05317 for <tcmay@got.net>; Fri, 29 Dec 1995 14:30:25 -0800 Date: Fri, 29 Dec 1995 14:30:25 -0800 X-Sender: tcmay@mail.got.net Message-Id: <ad0998a917021004d556@[205.199.118.202]> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: tcmay@got.net From: tcmay@got.net (Timothy C. May) Subject: Eternity.com announces "Eternal URLs"--version 1.02 X-UIDL: 820276233.000 ***Press Release*** Santa Cruz, CA. Eternity, Inc. is pleased to announce the availability of its permanent Uniform Resource Locater (URL) facility. For a fee, Eternity will store a file for a year, for several years, or for "eternity." Eternity will ensure that backups are escrowed in the event of interruptions at Eternity or even the demise of Eternity as an entity. Visit us at http://www.eternity.com/~products/ ***End*** Well, not really. But an example makes a point succinctly. There's a growing need for "eternal URLs," URLs that have enough persistence to last for a very long time, possibly for several decades. (And with declining storage costs, "several years" implies "eternity" only costs 10% more.) Here are some reasons: * Today's URLs are transient, fluid. Accounts go away and the URL no longer works, e.g., the large number of "Can't access" errors when Web surfing. (Many of these errors are because a server or account has been deliberately been taken down, for whatever reasons. Often because of overloading, which is a separable issue from the issue of permanence--overloading can be handled with access fees, for example.) * Web citations. Michael Froomkin, and others, have been raising the issue of using the Web for legal citations. A real problem if the citations don't persist for very long. (And I started seriously thinking about this Web transience issue when I wrote a reply to him pointing out the utter transience of most URLs, the "decay time" of valid URLs and how tough it would be to rely on the Web for citations which are intended to be valid for years or even decades.) * Many links have a "single-point failure" built in. Let me give an example: - my Cyphernomicon exists in an HTML version (nicely done by J. Rochkind) at the URL "http://www.oberlin.edu/~brchkind/cyphernomicon/". - lots of other Web pages have links to this URL. In fact, nearly every page that mentions the Cyphernomicon points to this URL! - so, what happens when Jonathan's account--at Oberlin I presume--goes away? What happens when he gets tired of maintaining it, or graduates, or whatever? - answer: all the pages that point to it now come up only with the typical errors. - it's unlikely that all or even most of the pages with pointers to this now-gone URL will update them. I call this "Web decay." Thus, we see the increasing breakage of links. (I don't know about you folks, but in my Web surfing I find more and more links broken every day....) A market fix might be the following: - a site operator offers "archival" storage, perhaps/probably for a fee - files could be placed in this archival storage for some fee for a given amount of time. (Given the declining cost of storage, a user might be able to economically buy "permanent" storage, sort of a "discounted future value" approach. Thus, I might pay $20 to store the Cyphernomicon for a year, $30 for 3 years, and $50 for "eternity." - he may also charge digital cash for access (a separable issue, but worth mentioning) - example URL: "http://www.eternity.com/~cypherpunks/cyphernomicon/" - the site, "eternity.com" in this example, would ensure that the document remains mounted and available for years, decades, etc. This could be done by using backup machines, copies of optical disks at services which agree (for a fee) to keep backups and mount them in the event of disruption/bankruptcy/etc. of "eternity.com," and so on. (Obviously a fee structure could include issues of file size, latency of access, policies for public hits on the site, etc.) - services like this (and I expect more to appear) may have cross-backup provisions, or arrangements to take over the good name and good will, and of course the files, of services which vanish or go bankrupt. (All sorts of messy details, but familiar to lawyers handling escrow matters.) - there are obvious similarities with "archival storage" services (the "data vaults" and salt mine companies). In this case, the archival storage also has access via the Web attached. (And yes, an obvious wrinkle is to sell archival storage per se, with access a separate issue: access could be via passwords/crypto, or via paid access, URLs, etc. All separable. But the "market focus" on "eternal URLs" is a powerful focus, likely to quickly generate a fair amount of business.) (Strategies for site-mirroring of URLs, where the same URL actually involves multiple sites, is another approach. I'm not following that area too closely, so I won't discuss it here. It may be a workable alternative.) Another alternative is for services to arise which act as redirectors of Web accesses. Without actually storing the Cyphernomicon file, for example, they tell users where it actually is. (Not that much different from Infoseek, DejaNews, Alta Vista, etc., except that those services merely index existing pages, which may have huge numbers of corrupt links, while the service I am proposing would take active steps to ensure valid copies can be accessed...probably too much work to be economical, which is why I prefer the "Eternity.com" model: the owner of a URL, or an interested party who wishes to pay to store a copy, takes active steps to ensure a permanent copy exists. There are all sorts of wrinkles of this idea, such as: -- newer versions of a file, e.g., the "Cyphernomicon v.1.5," are either stored separately, with pointers added to the first file, or are appended. I favor the "pure archive" approach of always having the earlier versions stored. ("Once stored, it is never forgotten.") For example: "http://www.eternity.com/~cypherpunks/cyphernomicon/0.666" (the original) "http://www.eternity.com/~cypherpunks/cyphernomicon/1.5" "http://www.eternity.com/~cypherpunks/cyphernomicon/2.0" ...etc.... -- obviously files could be stored in various ways, depending on fees per storage and fees per access. Older versions might be archived on DAT (or its 2005 equivalent), more recent versions might be on DVDs, CD-ROMs, etc., and heavily-accessed files might be on magnetic disk. All a matter of pricing, usage, market issues. -- jukeboxes of CD-ROMs, DATs, and DVDs should make storage of "archived Web sites" very cheap. -- such a service could also be a protection against political pressure: once a file is stored, perhaps in multiple national jurisdicitions, or perhaps even in unknown jurisdictions via Web mixes, the file could not be removed. -- digital timestamps and other hashes of the database could be published, a la Haber and Stornetta's Surety service, to ensure that that the database had not been tampered with. -- secure data havens, such as Swiss banks (maybe not so secure, but you get the point) could store copies of the files, perhaps on very slow media. Enough to ensure eternal storage. Underground vaults, salt mines, the usual shtick. I'll close for now. Could "Eternity.com" be the new Westlaw? (For you nonlawyers, Westlaw publishes books of court cases and rulings, and is the de facto place for references...they make a tidy profit by licensing their system. Cyberspace legal thinkers are looking at Web alternatives.) Food for thought (and grounds for further research, as Dave Emory would say). --Tim May We got computers, we're tapping phone lines, we know that that ain't allowed. ---------:---------:---------:---------:---------:---------:---------:---- Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay@got.net 408-728-0152 | anonymous networks, digital pseudonyms, zero W.A.S.T.E.: Corralitos, CA | knowledge, reputations, information markets, Higher Power: 2^756839 - 1 | black markets, collapse of governments. "National borders aren't even speed bumps on the information superhighway."

BTW, I went to look this up in the Cyphernomicon (I sorta think it's reffed in there), but the first 4 sites I saw on Altavista were all dead-end broken links. The Web's ripping... what's the current Preferred URL?

First hit I got at hotbot was the standard one http://www.oberlin.edu/~brchkind/cyphernomicon/ and it seems to work fine. Also http://yak.net/CYPHERNOMICON.gz works. Thanks! Bill Bill Stewart, bill.stewart@pobox.com PGP Fingerprint D454 E202 CBC8 40BF 3C85 B884 0ABE 4639

Jim Gillogly wrote:

Yes, that's definitely better for high-confidence long-term archival stuff than relying on one cipher. Carl Ellison's suggestion was DES | tran | nDES | tran | DES, where "tran" is an unkeyed large-block transposition.

One other possibility is to encrypt with plaintext block chaining, then superencrypt it PBC in reverse order, starting with the last block first. An attacker would thus have to decrypt the entire message before knowing whether the key was correct or not.

One word of caution (which should be obvious, but can't hurt to repeat it): if you chain ciphers (e.g. DES | IDEA | 3DES | CAST | Blowfish), be sure to use separate keys for each of them; otherwise breaking the last one will give the key to the whole lot.

Only if the cryptanalyst knows that the decryption of the last one was correct, which shouldn't be possible without also decrypting all the other layers.