From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,9bb56e94a4c5bb5e X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news4.google.com!newsfeed2.dallas1.level3.net!news.level3.com!news.illinois.net!attcg1!ip.att.net!news.binc.net!kilgallen From: Kilgallen@SpamCop.net (Larry Kilgallen) Newsgroups: comp.lang.ada Subject: Re: How unchecked conversion works? Date: 16 Jan 2005 18:34:22 -0600 Organization: LJK Software Message-ID: <4zSInARGfY3p@eisner.encompasserve.org> References: <8PwGd.8282$pZ4.6177@newsread1.news.pas.earthlink.net> NNTP-Posting-Host: eisner.encompasserve.org X-Trace: grandcanyon.binc.net 1105922053 17979 192.135.80.34 (17 Jan 2005 00:34:13 GMT) X-Complaints-To: abuse@binc.net NNTP-Posting-Date: Mon, 17 Jan 2005 00:34:13 +0000 (UTC) Xref: g2news1.google.com comp.lang.ada:7854 Date: 2005-01-16T18:34:22-06:00 List-Id: In article <8PwGd.8282$pZ4.6177@newsread1.news.pas.earthlink.net>, Jeffrey Carter writes: > He had achieved everything except there was one small covert channel > available. A trusted user could set up a program that created a lot of > processes when it wanted to transmit a one, and no processes to transmit > a zero. The untrusted recipient would create a process from time to time > and see how many processes had been created, since process IDs were > sequential. Analysis of such covert storage channels is actually required for any assurance level above B1, not just for A1. http://www.atis.org/tg2k/_covert_storage_channel.html > It seems to me that this system was a success. Nothing stops the trusted > person from memorizing a block of data, going out of the secure area, > writing it down, and giving it to the recipient. But the person doing that would know they were doing that. No computer system can prevent a human from releasing information they know, even if they have to carry one bit a day out of the workplace based on which of their pockets they use to store their wallet. A trusted system (at the proper evaluation level) will prevent the person from _inadvertantly_ releasing information, such as by running a trojan horse spreadsheet program that performed the modulation you describe.