December 2003 - cypherpunks-legacy

Re: Detweiler Remailer filtering
by qwerty＠netcom.com 17 Dec '03

17 Dec '03

-----BEGIN PGP SIGNED MESSAGE----- Hal told the oral history of my remailer as... >I suggest, then, that you run a remailer (it only costs $20 a month on the >system I use), and publicize the fact that Detweiler can use yours with >impunity. Set up a mail-to-news gateway that other remailer operators can >use so that they don't have to worry about the consequences of abuse. >It's easy to talk about sacred ideas, but perhaps not so easy to keep an >unpopular and misunderstood remailing infrastructure in place. "Xenon" >also accused us of hypocrisy, started up a remailer, and stopped it in just >a couple of days faced with these kinds of problems. However, I experienced *no* abuse of my remailer, I being at the time on fairly good terms with Mr. Detweiler. (I had a single amusing "abuse" in which the person told someone in personal anonymous mail that their continued us of their IP number was a copyright violation and would be procecuted. Guy just didn't have a sense of humour.) I did not accuse anyone of hypocrisy. All I said was that a simple quick fix solution of blocking his known address would ONLY MAKE THINGS WORSE, since then he would forge mail instead. Besides, fight him and he'll fight back with renewed energy, I reasoned. I also thought it was sort of funny to see all the propellor-beenie types yelling at the top of their lungs about some inappropriate posting in their oh so precious newsgroups, and said that his posts could be called performance art. I said we needed an *abuse* filter not a Detweiler filter. This of course got me flamed :-). I shut down qwerty-remailer, after perhaps a month of operation, due to two reasons. I felt moderated remailers were necessary (until Usenet is "fixed" to catch such abuses in some open moderation scheme) and did not have the *time* to moderate qwerty. The major reason however was the public threats of other remailer operators sending *their* abusive user's mail through qwerty-remailer when I refused to block Detweiler's address! That threw me for a loop. Wow. Nasty situation that was, and an isolated remailer is not an effective one. I also was not at all effective at trying to gather FULL information about the existing remailers, and my "Full Discosure Remailer List" is still incomplete, as well as now outdated. -=Xenon=- P.S. If anyone is interested in a few radical essays on remailer/internet security from an output larger than the internet, see the Rant Series on ftp.netcom.com in /pub/qwerty/Writings. -----BEGIN PGP SIGNATURE----- Version: 2.3a iQCVAgUBLinKgQSzG6zrQn1RAQE7JwQApnXmm35jUxq0QyAYEN+pJgPxnQE5Jcqz RJfMKNjNT/1LDkgRvKoJxCoYfzd9ga/nQvIZczwefAPI2Ko8Q7bLMh1zm/txZzN7 RnCVd8Hdhq9UpPue3rwZ037jRc6K/XTEwgeKT9Ct3tmIJDbu5FyMqsK4asT4fgFi b/8h2TZG7ks= =FemC -----END PGP SIGNATURE-----

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Re: Card Playing Protocol
by kentborg＠world.std.com 17 Dec '03

17 Dec '03

rarachel(a)prism.poly.edu writes about problems with card protocols, >Anyway, you can ask him about it, his address is rvslyke(a)prism.poly.edu I will once I am sure I will understand the answer. Thanks, -kb, the Kent who does have some reading ahead of him -- Kent Borg +1 (617) 776-6899 kentborg(a)world.std.com kentborg(a)aol.com Proud to claim 35:00 hours of TV viewing so far in 1994!

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Re: Card Playing Protocol?
by kentborg＠world.std.com 17 Dec '03

17 Dec '03

rarachel(a)prism.poly.edu writes some interesting looking details on crypto cards, but I am too exhausted to make sense of it tonight. I am not ignoring it. Thanks, -kb -- Kent Borg +1 (617) 776-6899 kentborg(a)world.std.com kentborg(a)aol.com Proud to claim 35:00 hours of TV viewing so far in 1994!

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Re: Key length security (calculations!)
by wcs＠anchor.ho.att.com 17 Dec '03

17 Dec '03

> solman(a)mit.edu writes (quoting someone else initially): > >What about Shamir's triple pass key exchange protocol (explained briefly > >below). Its the perfect key exchange algorithm. > >It obsoletes Public key systems entirely as long as you only need to > >exchange keys and not authenticate. [ A: Ea(K) B: Eb(Ea(K)) A: Da(Eb(Ea(K))) == Da(Ea(Eb(K))) == Eb(K) ] Some problems - commutative symmetric encryption algorithms aren't very common; the most obvious one ( M xor K ) doesn't work here, since you have known plaintext, making it trivial to find Ka and Kb, while the usable M**K mod p looks suspiciously close to Diffie-Hellman from a patent perspective, though Diffie-Hellman makes useful simplifications, as Hal points out. Also, an active eavesdropper can break it (maybe at the cost of reencrypting the entire conversation), which is the main weakness of Diffie-Hellman; authentication is still necessary in environments where this matters. Hal writes: > Also, this does not obsolete PK since it requires several exchanges > before communication can occur, making it inappropriate for high-latency > communications, such as for most email. Lots of email these days flows over SMTP connections, where a couple of extra messages at handshake time isn't a major problem, though it's really more applicable for link encryption than end-to-end, given the amount of mail that really goes through MX records or other mail gateways. It wouldn't be that hard, now that RSAREF includes Diffie-Hellman, to do a DH-SMTP and DH-POP, though the <censored> export regulations make it a bit annoying to use internationally, and you could just as well use Shamir's 3-way handshake if there's no patent problem. Bill Stewart

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Re: Card Playing Protocol?
by kentborg＠world.std.com 17 Dec '03

17 Dec '03

s009amf(a)discover.wright.edu writes: >The only problem is if a government spy is listening on this >conversation, he is going to learn how to play this game to and learn how >to intercept the messages and therefore learn how to decode the messages... Oh, I sure hope the spooks are listening, but I don't intend that their knowing the protocol will help them cheat at cards any more then having the PGP source will let them read messages encrypted by it. That is what cryptography is all about. Note, depending on how things land thrid parties might have no difficulty watching the play without a superencrypting--I don't yet know. -kb

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HR 3937 comes to the floor this wednesday with a "good" amendment!
by Shabbir J. Safdar 17 Dec '03

17 Dec '03

[updated July 18, 1994 shabbir] [HR 3937 COMES TO THE FLOOR WEDNESDAY JULY 20TH; YOUR ACTION NEEDED] [PLEASE CHECK THE "WHAT YOU CAN DO RIGHT NOW" SECTION!] ********************************************************************* DISTRIBUTE WIDELY ********************************************************************* Table of contents: Introduction & Alert Status of the bill What you can do right now List of legislators supporting HR 3937 (formerly HR 3627) List of legislators wavering on HR 3937 (formerly HR 3627) List of legislators opposing HR 3937 (formerly HR 3627) What is the Cantwell bill? ------------------------------------------------------------------------------- INTRODUCTION Voters Telecomm Watch keeps scorecards on legislators' positions on legislation that affects telecommunications and civil liberties. If you have updates to a legislator's positions, from either: -public testimony, -reply letters from the legislator, -stated positions from their office, please contact vtw(a)panix.com so they can be added to this list. General questions: vtw(a)panix.com Mailing List Requests: vtw-list-request(a)panix.com Press Contact: stc(a)panix.com Gopher URL: gopher://gopher.panix.com:70/1/1/vtw WWW URL: Be patient; we're working on it. :-) ------------------------------------------------------------------------------- STATUS OF THE BILL (updated 7/18/94) The Cantwell bill HR3627, that allows for fewer restrictions on exports of cryptography, was rolled into the General Export Administration Act HR 3937. The House Foreign Affairs Committee passed the full strength version out of committee after open, public hearings. The House Intelligence Committee took the bill and gutted it after a day of closed, secret hearings. The gutted version will come to the House floor on Wednesday July 20th. A amendment that reinstates Rep. Maria Cantwell's cryptography export provisions WILL be offered. It is crucial that you ensure that your representative knows that you support ONLY the amended version of this bill. This may be the last thing you can do for the cryptographic export legislation. Take the time to make a call! Schedule/Chronology of the bill Jul 20, 94 HR3937 comes to House floor; a "good" amendement will be offered [YOUR ACTION IS NEEDED TO PASS THIS] Jul 11, 94 House Rules Committee marks HR3937 "open"; allowing amendments Jun 30, 94 [*** vote postponed, perhaps till the week of 7/11/94] House Rules Comm. decides whether to allow amendments on the bill when it reaches the House floor Jun 14, 94 Gutted by the House Select Committee on Intelligence May 20, 94 Referred to the House Select Committee on Intelligence May 18, 94 Passed out of the House Foreign Affairs Committee on May 18 attached to HR 3937, the General Export Administration Act Dec 6, 93 Referred to the Subcommittee on Economic Policy, Trade and Nov 22, 93 Referred to the House Committee on Foreign Affairs. ------------------------------------------------------------------------------- WHAT YOU CAN DO RIGHT NOW Estimated time to do this good deed: Six minutes Your legislator needs to know that you want them to support HR3937 but only with an amendment including Rep. Maria Cantwell's cryptography export provisions. If you wish to fax a letter instead of calling, that's fine too. If you don't know who your representative is, call: -The League of Women Voters in your area, or -Any representative from your state. They will tell you which is yours. You can obtain a complete copy of all representatives by: -checking the VTW gopher site: URL:gopher://gopher.panix.com:70/1/1/vtw (check under Congress) -or by dropping a note to vtw(a)panix.com [Our directory is a bit out of date. Please check all fax numbers before sending. People volunteering to obtain a new directory for us are welcome to help out.] Feel free to use the following sample communique: The Honorable ____________ address Washington DC, 20515 Dear Congressman or Congresswoman, On Wed. July 20th, HR 3937 (General Export Administration Act) comes to the floor. Please support HR3937 but only with an amendment including Rep. Maria Cantwell's cryptography export provisions. These provisions are crucial to the development of privacy-enhancing technology as the competitiveness of the American cryptographic industry. Sincerely, _________________________________ A shorter telephone sample communique might be: Dear Congressman or Congresswoman, Please support HR3937 but only with an amendment including Rep. Maria Cantwell's cryptography export provisions. Thank you. ------------------------------------------------------------------------- LIST OF LEGISLATORS SUPPORTING CRYPTOGRAPHY EXPORT LEGISLATION The following legislators have formally registered support for cryptography export legislation. Call them with your cheers. All addresses are Washington, D.C. 20515 Dist ST Name, Address, and Party Phone Fax ==== == ======================== ============== ============== 1 WA Cantwell, Maria (D) 1-202-225-6311 1-202-225-2286 1520 LHOB HR 3627's sponsor; thank her for her work! 16 IL Manzullo, Donald (R) 1-202-225-5676 1-202-225-5284 506 Cannon Cosponsored HR 3627 on 11/22/93 3 UT Orton, William H. (D) 1-202-225-7751 1-202-226-1223 1122 LHOB Cosponsored HR 3627 on 03/22/94 3 OR Wyden, Ronald (D) 1-202-225-4811 1-202-225-8941 1111 LHOB Cosponsored HR 3627 on 03/22/94 16 CA Edwards, Donald (D) 1-202-225-3072 1-202-225-9460 2307 RHOB Cosponsored HR 3627 on 03/22/94 19 OH Fingerhut, Eric D. (D) 1-202-225-5731 1-202-225-9114 431 Cannon Cosponsored HR 3627 on 03/22/94 4 MA Frank, Barney (D) 1-202-225-5931 1-202-225-0182 2404 RHOB Cosponsored HR 3627 on 03/22/94 2 UT Shepherd, Karen (D) 1-202-225-3011 1-202-226-0354 414 Cannon Cosponsored HR 3627 on 03/22/94 3 WA Unsoeld, Jolene (D) 1-202-225-3536 1-202-225-9095 1527 LHOB Cosponsored HR 3627 on 03/22/94 19 FL Johnston II, Harry (D) 1-202-225-3001 1-202-225-8791 204 Cannon Cosponsored HR 3627 on 03/22/94 9 WA Kreidler, Mike (D) 1-202-225-8901 1-202-226-2361 1535 LHOB Cosponsored HR 3627 on 03/22/94 4 WA Inslee, Jay (D) 1-202-225-5816 1-202-226-1137 1431 LHOB Cosponsored HR 3627 on 03/22/94 7 WA McDermott, James A. (D) 1-202-225-3106 1-202-225-9212 1707 LHOB Cosponsored HR 3627 on 03/22/94 8 IN McCloskey, Frank (D) 1-202-225-4636 1-202-225-4688 306 Cannon Cosponsored HR 3627 on 03/22/94 14 CA Eshoo, Anna G. (D) 1-202-225-8104 1-202-225-8890 1505 LHOB Cosponsored HR 3627 on 03/22/94 10 NC Ballenger, Thomas C. (R) 1-202-225-2576 1-202-225-0316 2238 RHOB Cosponsored HR 3627 on 05/04/94 2 WA Swift, Al (D) 1-202-225-2605 1-202-225-2608 1502 LHOB Cosponsored HR 3627 on 05/04/94 ------------------------------------------------------------------------------- LIST OF LEGISLATORS WAVERING ON CRYPTOGRAPHY EXPORT LEGISLATION [Feel free to use the sample communique at the end of the FAQ when calling or writing a legislator.] 26 NY Hinchey, Maurice D. (D) 1-202-225-6335 1-202-226-0774 1313 LHOB Recently told a constituent that he is taking the Cantwell bill under consideration, but has "national security concerns" about allowing encryption to be exported outside the United States. 1 IA Leach, James (R) 1-202-225-6576 1-202-226-1278 2186 RHOB Has yet to answer a constituent letter with a stated position. 13 NY Molinari, Susan (D) 1-202-225-3371 1-202-226-1272 123 Cannon Has yet to answer a constituent letter with a stated position. (has taken inordinately long) 8 NY Nadler, Jerrold (D) 1-202-225-5635 1-202-225-6923 424 Cannon Met with lobbying constituent in April '94; no position taken yet 25 CA McKeon, Howard P. (R) 1-202-225-1956 1-202-226-0683 307 Cannon Responded to a constituent with a "non-position", May '94 Had a favorable meeting with a constituent and a VTW volunteer in May '94. ------------------------------------------------------------------------------- LIST OF LEGISLATORS OPPOSING CRYPTOGRAPHY EXPORT LEGISLATION [Feel free to use the sample communique at the end of the FAQ when calling or writing a legislator.] Dist ST Name, Address, and Party Phone Fax ==== == ======================== ============== ============== 5 AL Cramer Jr, Robert E. (D) 1-202-225-4801 1-202-225-4392 1318 LHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 8 CA Pelosi, Nancy (D) 1-202-225-4965 1-202-225-8259 240 Cannon FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 32 CA Dixon, Julian C. (D) 1-202-225-7084 1-202-225-4091 2400 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 40 CA Lewis, Jerry (R) 1-202-225-5861 1-202-225-6498 2312 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 46 CA Dornan, Robert K. (R) 1-202-225-2965 no reliable fax 2402 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 2 CO Skaggs, David E. (D) 1-202-225-2161 1-202-225-9127 1124 LHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 10 FL Young, C. W. (R) 1-202-225-5961 1-202-225-9764 2407 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 4 KS Glickman, Daniel (D) 1-202-225-6216 1-202-225-5398 2371 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 1 NE Bereuter, Douglas (R) 1-202-225-4806 1-202-226-1148 2348 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 9 NJ Torricelli, Robert (D) 1-202-224-5061 1-202-225-0843 2159 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 3 NM Richardson, William (D) 1-202-225-6190 no reliable fax 2349 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 1 NV Bilbray, James H. (D) 1-202-225-5965 1-202-225-8808 2431 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 17 PA Gekas, George W. (R) 1-202-225-4315 1-202-225-8440 2410 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 2 RI Reed, John F. (D) 1-202-225-2735 1-202-225-9580 1510 LHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 14 TX Laughlin, Gregory H. (D) 1-202-225-2831 1-202-225-1108 236 Cannon FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 16 TX Coleman, Ronald D. (D) 1-202-225-4831 None 440 Cannon FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 19 TX Combest, Larry (R) 1-202-225-4005 1-202-225-9615 1511 LHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 1 UT Hansen, James V. (R) 1-202-225-0453 1-202-225-5857 2466 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. 6 WA Dicks, Norman D. (D) 1-202-225-5916 1-202-226-1176 2467 RHOB FAILED Cryptography exports: Voted to kill Rep. Cantwell's export provisions in the House Intelligence Committee on 6/15/94. ------------------------------------------------------------------------------- What is the Cantwell bill? The Cantwell bill would permit companies to export products with encryption technology in them. US companies are currently not permitted to export products (hardware or software) with this technology in them. What is encryption technology? Encryption technology, or cryptography, is the art of scrambling a conversation so that only the people communicating can decode it. Other people (such as eavesdroppers) cannot learn about the conversation. Where is cryptography being used? Cryptography is used to encrypt electronic mail to protect its confidentiality in transit. It's used by bank automatic teller machines to protect sensitive data (such as your account number, your Personal Identification Number, and your bank balance). It can be implemented into software (such as electronic mail programs and word processors) as well as hardware (such as telephones and "walkie-talkies") to ensure your privacy. Why is there a restriction on exporting products with technology in them? For many years the United States poured vast sums of money into cryptography. The US government thought that if they did not let this technology be exported, foreign individuals would not be able to obtain it and use it against us (by keeping US intelligence agencies from eavesdropping on their communications) Today, many companies selling cryptographic technology are producing their products for the global market. A recent Software Publishers' Association Report (available from the VTW gopher) identified over 200 non-US companies producing cryptographic technology in the global marketplace. You can buy the same, high-quality cryptographic technology from many international firms despite the US export regulations. Although the marketplace has changed, the regulations have not. Why should the regulations be changed? US companies compete in a global marketplace. Because of the export regulations, they often compete alongside products with superior cryptographic capabilities built into them. The result is that US companies build their products with an inferior encryption technology. The result of this is that you, as an American consumer, have great difficulty obtaining products with strong encryption in them. Because US products cannot compete against products with better privacy features, and because the laws are outdated, the regulations should be changed. The Cantwell bill fixes these regulations to more accurately resemble the current situation of the world marketplace. How can I help encourage more privacy-enhanced products and pass the Cantwell bill? Call or write your representative and ask them to support or cosponsor Rep. Cantwell's export provisions (formerly HR 3627) in the General Export Administration Act, HR 3937. You can base your letter on the sample communication below. SAMPLE LETTER OR PHONE CALL The Honorable ____________ address Washington DC, 20515 Dear Congressman or Congresswoman, As a citizen concerned for my privacy, as well as a supporter of American business, I urge you to cosponsor the Rep. Cantwell's cryptographic export provisions (formerly HR 3627) in the General Export Administration Act, HR 3937. The bill would allow US companies to produce and export products with cryptographic privacy-enhancing technology in them. These products are already available from firms throughout the world. US companies lose nearly $100 million per year in exports to them. By encouraging this industry, ordinary citizens like you and me would be able to purchase products with better privacy features. Please support or co-sponsor HR 3937. Sincerely, ___________________________________ -------------------------------------------------------------------------------

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PROTOCOLS: Re: Hashed Hash
by wcs＠anchor.ho.att.com 17 Dec '03

17 Dec '03

> I'm planning on implementing the "cryptographic protection of databases" > on page 61 of Schneier, to create a directory of a professional > organization that would be useless to telemarketers. > [hash last name to get DES key and location of encrypted data in list.] > [ problems of brute-force and popular-last-names attacks ] If you're only concerned about telemarketers, this amount of obscurity may be enough - anybody competent enough to hash a list of, say, 10000 last names x 1000 first names into your database is at least an *interesting* telemarketer :-) If you're concerned about telemarkers from the NSA/FBI/KGB, then the algorithm isn't enough anyway, because even if you make the search space large/slow enough to make it hard to list the whole list, it's still easy to look up "Goren" or "Stewart" or "McCarthy" to see if they're card-carrying members; it won't protect the usual suspects. An intermediate variant is to use a password as part of the hash; if everybody has their own password, the table size is N**2, or you can give everyone the same password without increasing the table size, and still be able to distribute the list on FTP. [This version is probably most useful for Secret Societies, where key distribution and privacy are taken seriously - the Masons could use a 33*N-entry hash table, and you *still* wouldn't be able to tell whether any members were the Illuminati! :-) ] By giving everyone different passwords and adding logN dummy records to the database, you could also tell whose copy was leaked (if only one copy leaks out; you obviously need more entries to detect multiple leaks.) On the question of whether there are functions I(m) = H(H(m)) for popular hashes, by definition there are, since H(H(m)) is one. For most of the cryptographically useful functions, though, there aren't any that are faster than running the hash function twice. Some exceptions are hashes like a**x mod p, x**a mod p, and obviously (a*x+c) mod p. But DES is known not to be a group, and MD5 is ugly enough it probably isn't group-like either. Bill

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Bankless cash system?
by nobody＠vox.hacktic.nl 17 Dec '03

17 Dec '03

-----BEGIN PGP SIGNED MESSAGE----- >... Okamoto & Ohta's bankless cash system ... How does this work? Where can I get more information about it? If it's as good as it sounds, I will code it. Pr0duct Cypher -----BEGIN PGP SIGNATURE----- Version: 2.3a iQCVAgUBLimznsGoFIWXVYodAQEcdAP/c/0mQtHRWAq+3L/kbbcwG0iauEMjtQ+t W2py+L32CfnfeYtz9olBpOm37s9/uXj25RnKMveiiUFEgo43fGGKqfyQIYVqhRtu VFmQ3GjatguOv8V5mStnaKQFEhhfW8R/eosmbnoZKXm+t+DsPZIrCSXKo97EcyXn HnCXUJfGEfY= =bv0R -----END PGP SIGNATURE-----

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Board games
by apoulter＠nyx.cs.du.edu 17 Dec '03

17 Dec '03

Timothy May writes:- >An obvious problem with crypto card games is this: what does it >provide that is worth the extra effort of doing encryption? Quite so. What other sorts of games are there that could benefit from crypto? There are a large number of multiplayer board games which combine high levels of complexity in move options with the necessity for inter-player diplomacy. Such board games are suitable for play-by-email (PBEM), as players need time to negotiate and work out moves. They generally work by requiring all players to submit orders for their move by a deadline. Problems with PBEM of such games revolve around having to persuade one person to sit out and adjudicate player moves (the luckless 'games master' or GM). There is a die roll server (send 'help' to dice(a)danpost4.uni-c.dk for details) which can provide die rolls for game functions but a person is still needed to request the appropriate die rolls to resolve player orders. The solution here is crypto. You can do away with the need for an extra person as GM by having one of the players act as GM (the 'player-GM') and resolve moves for each turn. Since all moves are due by one deadline there is the risk that the player-GM can move in response to other player's moves which have been sent to the player-GM for resolution. To prevent this the player-GM must make their move before all the other players. If done using plain text this puts the player-GM at a disadvantage so their orders are encrypted before emailing to all other players. These encrypted orders cannot then be changed in response to other player orders. During move resolution all player orders are published. This benefits all players in that they can check that the player-GM has resolved their orders correctly (when using a non-player GM order resolution is typically hidden). These published orders would include the decrypt pass phrase for the player-GM's orders, and the plain text of those orders. It would be incumbent on one or more of the players to be able to decrypt the player-GM's orders using the decrypt pass phrase, just to check that when decrypted they match the plain text version. Player-GM offers other advantages as well. For example, players can swap the onerous role of player-GM to allow for holidays etc. Using a non-player GM, if that person drops out then the game dies. Player-GM also allows short deadlines, each successive deadline being handled by a different player-GM, which speeds up the game and spreads the GMing load. Another use of a non-player GM is to hold secret agreements between players. Using player-GM this is no longer possible, but public/private key-based encryption can be used to allow players to sign secret treaties with each other. There is a specific forfeit in many game rules for breaching a signed treaty, so the need exists to make secret deals that can later be verified by players not in on the secret deal. Once public keys have been exchanged by players then secret treaties are no problem. Persuading gamers to use crypto to play multiplayer board games PBEM does not take much doing. If no one wants to be a non-player GM (and few do) then without crypto there is no game. I am currently playing in a 7-player PBEM board game called 'Empires of the Middle Ages' using the player-GM method. We use PGP as it supports the encryption facilities needed, runs on the various platforms different players use and is free. However, player-GM and crypto have yet to make an impact in the PBEM gamer community. This community is small and the ownership of particular games is limited. The game I am playing player-GM, 'Empires of the Middle Ages', although an excellent game, has been out of print nearly 15 years. I will be trying to start other board games using crypto and player-GM in the near future. Watch rec.games.board and rec.games.pbm for announcements. I should mention that player-GM is not the only solution to the GM problem. Another answer is to code a email-driven program which will adjudicate orders. Here the problem is the inherent complexity of many board games. The most successful adjudicator program to my knowledge is the Diplomacy judge (send 'help' to judge(a)morrolan.eff.org for details). Diplomacy is a relatively simple board game set loosely in Europe prior to the Great War. As the game name suggests, players can only win the game by good diplomacy, as military skills are not enough on their own. Many thousands of people play PBEM Diplomacy and its variants (games which change certain rules and/or map features from the standard game). Although the Diplomacy judge allows anonymous opponents and faked email in certain Diplomacy variants, it has no built-in facilities for use of public keys, which seems to me a strange omission. More information on the Diplomacy Judge can be found in the FAQ for rec.games.diplomacy. Alan Poulter (apoulter@nyx.cs.du.edu/a.poulter@lut.ac.uk)

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Crypto Games
by Daniel Carosone 17 Dec '03

17 Dec '03

I'd like to float a few ideas on this, generated by cutting right back to fundamental objectives. In his orignal posting, Kent Borg wrote: > It would be really nice if people had practical experiance *using* > cryptography in a friendly, innocent, and non-threatening way. > > How to do this? What about a multi-player game which requires > cryptography to implement the play? A lovely idea. I think that the `requires' above is fundamental, since our objective is to raise awareness of crypto -- not only for the obvious purposes of sending secret messages, but as a basic, useful, and necessary tool for many other applications. Ideally, it should be a game which simply cannot be reasonably played without the use of crypto, a point Tim was driving towards earlier. Additionally, the actual use of encrypted messages must be visible to all parties (and outsiders) as Kent pointed out in his original posting. Without intending to rain on anyone's parade, I think that the choice of a card game is probably not the best vehicle, for a number of reasons. Firstly, most card games are too close to realtime. While that is no great problem technically given internet-connected machines, it severely reduces the visibility of the underlying crypto -- people will be too busy playing with cards to look at the messages, and for the most part I suspect couldn't care if the messages were sent unencrypted. Card games certainly have both popular appeal, and (thanks to various `solitaire' programs) a good assosciation with computers to their advantage. However, I think we need a game that runs over a longer period, which requires (or at least allows for) periods of thought and contemplation between moves. Obvious examples are chess, or some of the play-by-mail type games. Indeed, it may well be worthwhile wandering over into some appropriate newsgroups and looking around, or asking a few questions -- it may well be that there are keen games programmers and players over there with a technical problem that could be solved with a bit of crypto. Since this is intended to be a political move, lets carefully look at what our political objectives are, and then choose (or even design) a game around them. Visibility of the usefulness of crypto, both to players and onlookers, is a key point. Ideally, then, a game that is played by posting an encrypted block to a public place such as a newsgroup for all the world to see, and that can be decoded by players to reveal (perhaps selective) information. This text block can then be captured and fed into the game program -- perhaps not until version 2 does this happen automatically :) It would be ideal if there were something from the game that could be recommended to be put in someone's .sig, perhaps a player code public key or something. This has great benefits for publicity, for instance in the past I've had a reasonable number of queries from net denizens asking `what is this PGP block stuff on the messages you post.. I keep seeing that around more and more'. It would be best if we can design the system to be distributed, and to operate without a central server (or with only a very minimal one), again to highlight the possibilities enabled by crypto. Perhaps players form playing groups amongst themselves using the keys in their .sigs and a group session key. Perhaps its a world-wide game that anyone can join. Maybe a central server issues a `turn key' to every player each week (or whatever play period) to enable them to make their next move. There's one sad consequence that will be hard to avoid.. while the posted messages may be cryptographically secure, it will be hard to come up with a solution whereby the game can be distributed in source form and not be vulnerable to cheating by source modification in the game-play parts of the code above the encryption. I think it is important that the code be distributed in source form, not only for practical reasons, but also to highlight that cryptography does *not* depend on keeping the cryptographic algorithm secret or obscured in any way. The game documentation can include detailed discussions of the cryto techniques and issues involved. The ability for the players to send encrypted messages to other players as part of the basic gameplay is important too. As has been pointed out, it is probably a good idea to keep the actual subject matter non-threatening. I keep thinking about the pbm-style empire-simulation games, perhaps because I've had some contact with them in the past, but that scenario isn't all that interesting for many people (including myself). Games of spies and secrecy and so on suggest themselves naturally, but maybe that assosciation does not need to be strengthened. A game for children might be a very good idea. There is a lot of activity currently in networking k12 schools to internet. One of the important challengers for teachers is finding appropriate educational uses for the technology. Foreign language students corresponding with native speakers and so on. For example, a game that lets students around the globe cooperate in solving problems and ferreting out clues may win wide appeal -- multiplayer distributed _Carmen_Sandiego_.. :) All the better to snub ITAR if it's an innocent game for kids. Should this game be written inside or outside the US? Any of you US citizens planning a move outside soon, who, when the game becomes wildly popular, can claim that the move was motivated by ITAR restrictions? :) > The cards would not be suitable for distributing porn, bomb making > secrets, or drugs, yet would drive the ITAR police *crazy*. What if a > deck of the these cards were to be illegally exported from the > country?!?!? Try telling all those Regular Citizens who are getting > on the net and discover they can play cards that the cards are > dangerous munitions. What a wonderful way to make the ITAR police > look completely silly. Oh, and to be sure they *do* get upset, make > the cards just open enough that they *do* constitute something more > general-purpose. (Make calls to PGP, or let others make calls to the > crypto functions in the digital cards--something like that.) Hmm.. :) > Comments? Suggestions for a game other than cards that would be > better or more suitable? See above for some generalised handwaving, at least. -- Dan.

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