Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site wdl1.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!genrad!decvax!ittatc!dcdwest!sdcsvax!sdcrdcf!hplabs!fortune!wdl1!jbn From: jbn@wdl1.UUCP Newsgroups: net.sources Subject: Obvious password detector (reposted) Message-ID: <879@wdl1.UUCP> Date: Sat, 23-Nov-85 01:25:37 EST Article-I.D.: wdl1.879 Posted: Sat Nov 23 01:25:37 1985 Date-Received: Wed, 27-Nov-85 01:22:15 EST Sender: notes@wdl1.UUCP Organization: Ford Aerospace, Western Development Laboratories Lines: 246 Nf-ID: #N:wdl1:64200002:000:12602 Nf-From: wdl1!jbn Nov 22 18:41:00 1985 /* Obvious password detection subroutine. Call: char word[]; char *obvious(word); Returns 0 if password is acceptable. Returns a pointer to a static message if the password is unacceptable. The algorithm used requires that the length of the password be within configurable length limits, and that the password not have triplet statistics similar to those associated with words in the English language. This is an inversion of a technique used to find spelling errors without a full dictionary. No word in the UNIX spelling dictionary will pass this algorithm. Users should be advised to pick a password composed of random letters and numbers. Eight randomly chosen letters will pass the algorithm over 95% of the time. A word prefaced by a digit will not pass the algorithm, although a word with a digit in the middle usually will. Two words run together will often pass. In the interest of greater network security, this algorithm is offered to the ARPANET community as a proposed standard technique for eliminating obvious passwords. John Nagle Ford Aerospace and Communications Corporation Western Development Laboratories 3939 Fabian Way Palo Alto, CA 94303 1/16/84 */ /* Table of triple usage in text 24511 words were used to make this table. The words came from the files: /usr/dict/words obvpats.lp The table is 30 percent populated. */ long obvtab[27][27] = { { 0X00100001, 0X00040000, 0X00040000, 0X00009000, 0X00808020, 0X00140000, 0X00000000, 0X00080000, 0X00000002, 0X00000000, 0X00000000, 0X00000000, 0X00001020, 0X00000000, 0X00000010, 0X00000020, 0X00000000, 0X00000000, 0X00000030, 0X00300100, 0X00000100, 0X00000000, 0X00000020, 0X00000000, 0X00000000, 0X00000000, 0X00000000 }, { 0X00090000, 0X000c708a, 0X022cd73e, 0X023ffbbe, 0X02fffffe, 0X002cd0da, 0X023cdae2, 0X02adf3b6, 0X0024f222, 0X00dd7efa, 0X00008022, 0X02b5937a, 0X06fdfbfe, 0X02bdf37e, 0X07ffdfff, 0X003c3248, 0X023dfb76, 0X00200000, 0X07fffffe, 0X02bbfbbe, 0X06bcfb6f, 0X055f7dfc, 0X02609232, 0X021cfbf6, 0X02999222, 0X00bdf3ff, 0X06308232 }, { 0X00080000, 0X07fdfbfc, 0X022c9226, 0X00008012, 0X00248222, 0X07dffbfe, 0X00200000, 0X00000000, 0X00208020, 0X047ffdfe, 0X00000020, 0X00000000, 0X02208222, 0X00800220, 0X0000a022, 0X03fdfffe, 0X00048000, 0X00000000, 0X02208222, 0X00308228, 0X00049062, 0X071efefc, 0X00000220, 0X00000020, 0X00000000, 0X049d11a2, 0X00000000 }, { 0X00080080, 0X02fffffe, 0X000c0020, 0X0024932a, 0X0000802a, 0X06bdf3fe, 0X00000002, 0X00248220, 0X02bdf3fe, 0X007df0fe, 0X00000000, 0X02bdfffe, 0X02208222, 0X00200222, 0X00008222, 0X07fffffe, 0X00000102, 0X00200000, 0X02308222, 0X00188200, 0X02aca262, 0X003df27e, 0X00000004, 0X00000000, 0X00000000, 0X001dd08e, 0X00000022 }, { 0X00088022, 0X06fd7bfc, 0X02249222, 0X00209102, 0X02249332, 0X07fff7fe, 0X00249282, 0X02a43a22, 0X00008222, 0X05fdf3fe, 0X00208022, 0X00000220, 0X02208222, 0X00208222, 0X00008223, 0X07fdf3fe, 0X00049322, 0X00200000, 0X02208222, 0X0091bb2a, 0X00008302, 0X043dfafe, 0X00008222, 0X02048222, 0X00000000, 0X00987aef, 0X00200000 }, { 0X004c1030, 0X04ff79dc, 0X023c9226, 0X023c9b3a, 0X02bdf3fe, 0X04ddfbfe, 0X023c92fa, 0X0224f3e6, 0X0224a222, 0X045d7afa, 0X00208022, 0X0218ca36, 0X02fdfbfe, 0X02a9f22e, 0X06ffffff, 0X05fd73d8, 0X02bdb32e, 0X00200000, 0X07fffffe, 0X02fbfbbe, 0X06bdfb6e, 0X005d78bc, 0X066c8222, 0X029df37e, 0X0333832a, 0X008df97f, 0X06648222 }, { 0X00080000, 0X07bc7bfe, 0X00000222, 0X0000000a, 0X00008002, 0X02fc7abe, 0X022cb366, 0X00000102, 0X00000022, 0X055c70fe, 0X00008000, 0X00000002, 0X02208222, 0X0000000a, 0X00000200, 0X03edf2be, 0X00000008, 0X00000000, 0X02208222, 0X00118922, 0X028ca32e, 0X041c74b8, 0X00000000, 0X00000002, 0X00000000, 0X00000000, 0X00000000 }, { 0X00080000, 0X06fdf3fc, 0X00008222, 0X00000000, 0X00008022, 0X02fdf3fe, 0X00240220, 0X020d93a2, 0X02bddffe, 0X047df0fe, 0X00000002, 0X00008200, 0X02208222, 0X02300222, 0X00318226, 0X02fdf3fe, 0X00009220, 0X00000000, 0X02208222, 0X00919b06, 0X00048302, 0X061cf2ee, 0X00000000, 0X02048022, 0X00000000, 0X00056002, 0X00000002 }, { 0X00080000, 0X06fdfbfe, 0X02249222, 0X00048102, 0X00048202, 0X07fff2ff, 0X00208202, 0X00008022, 0X00008122, 0X047dfcfe, 0X00000800, 0X00008220, 0X02248222, 0X0008a222, 0X0028c222, 0X06fdfeff, 0X00209202, 0X00200000, 0X02249232, 0X00108302, 0X02bdf3fa, 0X071d71fe, 0X00000200, 0X00008322, 0X00000000, 0X011d32be, 0X00000000 }, { 0X00483010, 0X05dd7bbc, 0X022cf226, 0X023cdb2a, 0X02bdf6b6, 0X04fd79fc, 0X0234d262, 0X063df3a2, 0X00000222, 0X00000202, 0X00208002, 0X02208a22, 0X02fdbbfe, 0X022df36e, 0X07ffffff, 0X05fd70be, 0X02bdb766, 0X00200000, 0X02fdfafe, 0X02ffffff, 0X06bdfb6f, 0X000c7008, 0X02248222, 0X00008202, 0X023082e2, 0X00000002, 0X04608022 }, { 0X00080000, 0X07ed7bbc, 0X00000000, 0X00000000, 0X00000000, 0X009cd57a, 0X00000000, 0X00000000, 0X00000000, 0X005070c4, 0X00000400, 0X00001000, 0X00000000, 0X00000000, 0X00000000, 0X02fc5bae, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X015d7e96, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000 }, { 0X00080000, 0X07fdfff4, 0X00248222, 0X00040302, 0X00048022, 0X02fdf3f6, 0X00208222, 0X00048000, 0X0014a022, 0X00ddf8fe, 0X00000002, 0X0000ca22, 0X0220a222, 0X00000022, 0X00208222, 0X01fdfb7a, 0X00009202, 0X00000000, 0X02208222, 0X02b1abae, 0X00048302, 0X029d7110, 0X00000000, 0X00008322, 0X00000000, 0X00ac9522, 0X00000000 }, { 0X00088000, 0X07fffbfe, 0X02249222, 0X0234b322, 0X02bdf36e, 0X07fdfffe, 0X00bc93e6, 0X00048222, 0X00008222, 0X05fffdfe, 0X00008000, 0X0288d322, 0X02bdb7fe, 0X0228e332, 0X00208020, 0X07fffffe, 0X021ca362, 0X00000000, 0X02208022, 0X0299ab26, 0X06eca326, 0X055dfefe, 0X00008222, 0X02008322, 0X00000000, 0X00bdfbfe, 0X00000022 }, { 0X00080000, 0X07fdffbc, 0X002dd236, 0X0021fbfe, 0X00008020, 0X07ddfbfe, 0X00209220, 0X00000000, 0X00208020, 0X053efcfa, 0X00000000, 0X00000000, 0X00008222, 0X0220a222, 0X02208222, 0X07fdfbfe, 0X023c9be6, 0X00200000, 0X00088002, 0X0239a37c, 0X00048120, 0X041dfaf8, 0X00000020, 0X00008222, 0X00000000, 0X001cd0a8, 0X00000000 }, { 0X00180000, 0X06fdfbfe, 0X002c922a, 0X02349b22, 0X02bffffe, 0X07fff3ff, 0X00249222, 0X02bdbb76, 0X02208222, 0X057ffbfe, 0X00208022, 0X021d33ea, 0X02008222, 0X00008222, 0X0228c222, 0X07fdf2fe, 0X00209220, 0X00200000, 0X0220822a, 0X02fdfbfe, 0X06adf3ee, 0X043dfafe, 0X02208222, 0X00048322, 0X00100200, 0X01ffb11e, 0X02808222 }, { 0X0008113c, 0X017f79da, 0X02fcd77e, 0X02349b2a, 0X02adfbfe, 0X037ef35c, 0X0234b262, 0X02bcf7f6, 0X0204f222, 0X011c58fe, 0X00008222, 0X02a99b2e, 0X06fdfbfe, 0X02aff36e, 0X07ffffff, 0X045df9dc, 0X02bffbae, 0X00200000, 0X06fffbfe, 0X02fbbbae, 0X02bdf3ee, 0X055f73ff, 0X02008a22, 0X06bdfb7e, 0X02d043ea, 0X001dd37e, 0X06008222 }, { 0X00080000, 0X07fffabc, 0X002c9022, 0X00008100, 0X00040002, 0X07fdfefe, 0X00241220, 0X00040002, 0X023cd232, 0X057ff8fa, 0X00000002, 0X00000220, 0X02208222, 0X00208022, 0X00008020, 0X03fdfafa, 0X022db322, 0X00040000, 0X02208222, 0X02b0bb2a, 0X0224832a, 0X041d7afe, 0X00000008, 0X00048202, 0X00000000, 0X00949b86, 0X00000000 }, { 0X00080000, 0X00100000, 0X00000000, 0X00000000, 0X00000000, 0X00000010, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00000000, 0X00020000, 0X00080000, 0X00000000, 0X00000000, 0X02008222, 0X00000000, 0X00000020, 0X00000000, 0X00000000, 0X00000000 }, { 0X00080010, 0X07fffffc, 0X022c9222, 0X023c9b2a, 0X02bdd366, 0X07ffffff, 0X00249222, 0X022cb322, 0X02208222, 0X07fbfdfe, 0X00208020, 0X029df336, 0X02b98236, 0X0239936e, 0X02b9ab66, 0X07fffffe, 0X023cb322, 0X00200000, 0X02248322, 0X02f3fb7e, 0X06bcf3ee, 0X01ddf2fe, 0X02208222, 0X00008222, 0X00000020, 0X0099f0be, 0X00008222 }, { 0X00081000, 0X03fdfffe, 0X02248222, 0X0224b323, 0X00248242, 0X07fffbfe, 0X02208222, 0X002c8220, 0X02f5fa6e, 0X057ff8fe, 0X00200000, 0X0224a222, 0X02208222, 0X02208222, 0X02208223, 0X06f5f7fe, 0X022c9326, 0X00200000, 0X00288222, 0X02bdf36e, 0X02edf7ff, 0X041df2fe, 0X00010220, 0X00248222, 0X00000000, 0X001d78bc, 0X00000000 }, { 0X001c1010, 0X03fdfbfc, 0X00248222, 0X02249102, 0X00048000, 0X03fdfbfe, 0X00249222, 0X00248022, 0X02bffbfe, 0X047ff8fe, 0X00000000, 0X02000222, 0X02208222, 0X00208222, 0X00308223, 0X07fdfafe, 0X00049222, 0X00000000, 0X02a08222, 0X02f1ab7e, 0X027c9be2, 0X031df2fe, 0X00000202, 0X01208322, 0X00000000, 0X01ad328e, 0X000db2a2 }, { 0X004c1010, 0X02dd7bdc, 0X027db736, 0X023c9b2a, 0X06ac92b6, 0X063df5f6, 0X0030b042, 0X002cf3a2, 0X00004002, 0X057dd0be, 0X00208202, 0X00048a30, 0X06fdfafe, 0X007bf36e, 0X02bdfbfe, 0X023d5210, 0X02bdbbfe, 0X00200000, 0X06fffbfe, 0X023bdbbe, 0X06bcf3be, 0X00202000, 0X00840220, 0X00000002, 0X00309220, 0X00601022, 0X04208022 }, { 0X00080000, 0X003d7fbc, 0X00004000, 0X00000000, 0X00000002, 0X039dfbfe, 0X00000000, 0X00000000, 0X00000000, 0X057cdafe, 0X00000000, 0X00000100, 0X00008002, 0X00000000, 0X00000000, 0X02bcfa88, 0X00000000, 0X00000000, 0X00008020, 0X00000800, 0X00000000, 0X000c1000, 0X02400220, 0X01000000, 0X00000000, 0X00800200, 0X00008000 }, { 0X00080000, 0X077d7bde, 0X00248222, 0X00208102, 0X02248220, 0X025d53bf, 0X00209202, 0X00000200, 0X02208222, 0X055d70f8, 0X00000000, 0X02804200, 0X02180222, 0X00000222, 0X02bd03fc, 0X00fdf864, 0X00209222, 0X00000000, 0X02008222, 0X02bdbb2c, 0X00208322, 0X00057100, 0X00000000, 0X00808002, 0X02000000, 0X0000f022, 0X02000000 }, { 0X00080000, 0X005870d8, 0X00000000, 0X00649322, 0X00000000, 0X021c7298, 0X00008000, 0X00201000, 0X00208202, 0X0058f0fe, 0X00000000, 0X00000000, 0X00000020, 0X00000000, 0X00000002, 0X001d6090, 0X00249222, 0X00200000, 0X00000000, 0X00000020, 0X02248326, 0X00051016, 0X00000200, 0X00008020, 0X01008000, 0X04041080, 0X00000000 }, { 0X004c1010, 0X0097f998, 0X00248232, 0X00009322, 0X0004c226, 0X00ddf0f6, 0X00201222, 0X0224f230, 0X02048020, 0X00094030, 0X00000002, 0X00004420, 0X00699a22, 0X0221e22e, 0X0310c3ba, 0X04fd78d8, 0X023dd322, 0X00200000, 0X0234c272, 0X0039b32e, 0X02108322, 0X00095b88, 0X00000022, 0X0004832a, 0X00000200, 0X02000000, 0X00000002 }, { 0X00080000, 0X00557b8e, 0X00000000, 0X00000000, 0X00000002, 0X00bc5a3e, 0X00000000, 0X00000020, 0X00000000, 0X003df0ae, 0X00000000, 0X00000000, 0X02008020, 0X00000002, 0X00000000, 0X0065e2b2, 0X00000002, 0X00000000, 0X00008002, 0X00000008, 0X00000020, 0X00040820, 0X00008020, 0X00008020, 0X00000008, 0X00002084, 0X06809222 } }; /* Configuration parameters */ #define MINLENGTH 5 /* minimum password length */ #define MAXLENGTH 8 /* maximum password length */ #define MINNOFIND 2 /* minimum unusual triples */ short unusual; /* count of unusual triples */ /* obvious -- test word for obviousness as password Words are rejected for being too short, too long, or looking too much like English words. */ char *obvious(word) /* returns msg or zero if OK */ char word[]; /* word to try */ { register int i = 0; /* for length */ while (word[i]) i++; /* compute length */ if (i < MINLENGTH) return("too short"); if (i > MAXLENGTH) return("too long"); unusual = 0; /* no unusual triples yet */ obvword(word); /* try the word */ if (unusual= 'a') && (ch <= 'z')) pat[i] = ch + 1 - 'a'; else if ((ch >= 'A') && (ch <= 'Z')) pat[i] = ch + 1 - 'A'; else pat[i] = 0; /* map into 0..26 */ } for (i=0; i < patcnt - 1; i++) /* for all triples */ { dotriple(pat[i],pat[i+1],pat[i+2]); /* do the triple */ } }