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diff --git a/doc/rfc/rfc1751.txt b/doc/rfc/rfc1751.txt new file mode 100644 index 0000000..846f920 --- /dev/null +++ b/doc/rfc/rfc1751.txt @@ -0,0 +1,844 @@ + + + + + + +Network Working Group D. McDonald +Request for Comments: 1751 NRL +Category: Informational December 1994 + + + A Convention for Human-Readable 128-bit Keys + +Status of this Memo + + This memo provides information for the Internet community. This memo + does not specify an Internet standard of any kind. Distribution of + the memo is unlimited. + +Introduction + + The Internet community has begun to address matters of security. + Recent standards, including version 2 of SNMP [GM93], have explicit + requirements for an authentication mechanism. These require use of a + keyed message-digest algorithm, MD5 [Riv92], with a key size of 128- + bits. A 128-bit key, while sufficiently strong, is hard for most + people to read, remember, and type in. This memo proposes a + convention for use with Internet applications & protocols using 128- + bit cryptographic keys. + +A Solution Already Exists + + The S/Key(tm) one-time password system [Hal94] uses MD4 (and now MD5, + as well) to compute one-time passwords. It takes the 128-bit result + of MD4 and collapses it to a 64-bit result. Despite the size + reduction, 64-bit one-time passwords are still difficult for ordinary + people to remember and enter. The authors of S/Key devised a system + to make the 64-bit one-time password easy for people to enter. + + Their idea was to transform the password into a string of small + English words. English words are significantly easier for people to + both remember and type. The authors of S/Key started with a + dictionary of 2048 English words, ranging in length from one to four + characters. The space covered by a 64-bit key (2^64) could be + covered by six words from this dictionary (2^66) with room remaining + for parity. For example, an S/Key one-time password of hex value: + + EB33 F77E E73D 4053 + + would become the following six English words: + + TIDE ITCH SLOW REIN RULE MOT + + + + + +McDonald [Page 1] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + + Because of the need for interoperability, it is undesirable to have + different dictionaries for different languages. Also, the current + dictionary only uses characters from the invariant portion of ISO- + 646. Finally, there is an installed base of users and applications + with this dictionary. + +The Proposal + + The code (see Appendix A) which S/Key uses to convert 64-bit numbers + to six English words contains two primitives which perform + conversions either way. The primitive btoe(char *engout,char *c) + takes a 64-bit quantity referenced by c and places English words in + the string referenced by engout. The primitive etob(char *out,char + *e) performs the opposite with an input string of English words + referenced by e, and by placing the 64-bit result into the buffer + referenced by out. + + The aforementioned primitives can be applied to both halves of a + 128-bit key, or both halves of a string of twelve English words. Two + new primitives (see Appendix B), key2eng(char *engout,char *key) and + eng2key(char *keyout,char *eng) serve as wrappers which call the + S/Key primitives twice, once for each half of the 128-bit key or + string of twelve words. + + For example, the 128-bit key of: + + CCAC 2AED 5910 56BE 4F90 FD44 1C53 4766 + + would become + + RASH BUSH MILK LOOK BAD BRIM AVID GAFF BAIT ROT POD LOVE + + Likewise, a user should be able to type in + + TROD MUTE TAIL WARM CHAR KONG HAAG CITY BORE O TEAL AWL + + as a key, and the machine should make the translation to: + + EFF8 1F9B FBC6 5350 920C DD74 16DE 8009 + + If this proposal is to work, it is critical that the dictionary of + English words does not change with different implementations. A + freely redistributable reference implementation is given in + Appendices A and B. + + + + + + + +McDonald [Page 2] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +Security Considerations + + This document recommends a method of representing 128-bit keys using + strings of English words. Since the strings of English words are + easy to remember, people may potentially construct easy-to-guess + strings of English words. With easy-to-guess strings comes the + possibility of a sentential equivalent of a dictionary attack. In + order to maximize the strength of any authentication mechanism that + uses 128-bit keys, the keys must be sufficiently obscure. In + particular, people should avoid the temptation to devise sentences. + +Acknowledgements + + S/Key is a registered trademark of Bell Communications Research. + + Thanks to Randall Atkinson for the bulk of the security + considerations section, and for general advice. Thanks to Phil Karn + and Neil Haller for producing the S/Key one-time password system, + which inspired this document. + +References + + [GM93] Galvin, J. and K. McCloghrie, "Security Protocols for version + 2 of the Simple Network Management Protocol (SNMPv2)", RFC 1446, + Trusted Information Systems, Hughes LAN Systems, April 1993. + + [Hal94] Haller, N., "The S/Key(tm) One-Time Password System", + Proceedings of the Symposium on Network & Distributed Systems + Security, Internet Society, San Diego, February 1994. + + [Riv92] Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321, + MIT Laboratory for Computer Science and RSA Data Security, Inc., + April 1992. + +Author's Address + + Daniel L. McDonald + United States Naval Research Laboratory + Code 5544 + 4555 Overlook Ave. SW + Washington, DC 20375 + + Phone: (202) 404-7122 + EMail: danmcd@itd.nrl.navy.mil + + + + + + + +McDonald [Page 3] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +Appendix A - Source for S/Key 8-bytes to/from Words Routines (put.c) + +/* This code originally appeared in the source for S/Key(TM), + * available in the directory + * ftp://thumper.bellcore.com/pub/nmh + * + * It has been modified only to remove explicit S/Key(TM) references. + */ + +#include <stdio.h> +#include <string.h> +#include <assert.h> +#include <ctype.h> + +#ifdef __STDC__ +#define __ARGS(x) x +#else +#define __ARGS(x) () +#endif + +static unsigned long extract __ARGS((char *s,int start,int length)); +static void standard __ARGS((char *word)); +static void insert __ARGS((char *s, int x, int start, int length)); +static int wsrch __ARGS((char *w,int low,int high)); + +/* Dictionary for integer-word translations */ +char Wp[2048][4] = { "A", "ABE", "ACE", "ACT", "AD", "ADA", "ADD", +"AGO", "AID", "AIM", "AIR", "ALL", "ALP", "AM", "AMY", "AN", "ANA", +"AND", "ANN", "ANT", "ANY", "APE", "APS", "APT", "ARC", "ARE", "ARK", +"ARM", "ART", "AS", "ASH", "ASK", "AT", "ATE", "AUG", "AUK", "AVE", +"AWE", "AWK", "AWL", "AWN", "AX", "AYE", "BAD", "BAG", "BAH", "BAM", +"BAN", "BAR", "BAT", "BAY", "BE", "BED", "BEE", "BEG", "BEN", "BET", +"BEY", "BIB", "BID", "BIG", "BIN", "BIT", "BOB", "BOG", "BON", "BOO", +"BOP", "BOW", "BOY", "BUB", "BUD", "BUG", "BUM", "BUN", "BUS", "BUT", +"BUY", "BY", "BYE", "CAB", "CAL", "CAM", "CAN", "CAP", "CAR", "CAT", +"CAW", "COD", "COG", "COL", "CON", "COO", "COP", "COT", "COW", "COY", +"CRY", "CUB", "CUE", "CUP", "CUR", "CUT", "DAB", "DAD", "DAM", "DAN", +"DAR", "DAY", "DEE", "DEL", "DEN", "DES", "DEW", "DID", "DIE", "DIG", +"DIN", "DIP", "DO", "DOE", "DOG", "DON", "DOT", "DOW", "DRY", "DUB", +"DUD", "DUE", "DUG", "DUN", "EAR", "EAT", "ED", "EEL", "EGG", "EGO", +"ELI", "ELK", "ELM", "ELY", "EM", "END", "EST", "ETC", "EVA", "EVE", +"EWE", "EYE", "FAD", "FAN", "FAR", "FAT", "FAY", "FED", "FEE", "FEW", +"FIB", "FIG", "FIN", "FIR", "FIT", "FLO", "FLY", "FOE", "FOG", "FOR", +"FRY", "FUM", "FUN", "FUR", "GAB", "GAD", "GAG", "GAL", "GAM", "GAP", +"GAS", "GAY", "GEE", "GEL", "GEM", "GET", "GIG", "GIL", "GIN", "GO", +"GOT", "GUM", "GUN", "GUS", "GUT", "GUY", "GYM", "GYP", "HA", "HAD", +"HAL", "HAM", "HAN", "HAP", "HAS", "HAT", "HAW", "HAY", "HE", "HEM", +"HEN", "HER", "HEW", "HEY", "HI", "HID", "HIM", "HIP", "HIS", "HIT", + + + +McDonald [Page 4] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +"HO", "HOB", "HOC", "HOE", "HOG", "HOP", "HOT", "HOW", "HUB", "HUE", +"HUG", "HUH", "HUM", "HUT", "I", "ICY", "IDA", "IF", "IKE", "ILL", +"INK", "INN", "IO", "ION", "IQ", "IRA", "IRE", "IRK", "IS", "IT", "ITS", +"IVY", "JAB", "JAG", "JAM", "JAN", "JAR", "JAW", "JAY", "JET", "JIG", +"JIM", "JO", "JOB", "JOE", "JOG", "JOT", "JOY", "JUG", "JUT", "KAY", +"KEG", "KEN", "KEY", "KID", "KIM", "KIN", "KIT", "LA", "LAB", "LAC", +"LAD", "LAG", "LAM", "LAP", "LAW", "LAY", "LEA", "LED", "LEE", "LEG", +"LEN", "LEO", "LET", "LEW", "LID", "LIE", "LIN", "LIP", "LIT", "LO", +"LOB", "LOG", "LOP", "LOS", "LOT", "LOU", "LOW", "LOY", "LUG", "LYE", +"MA", "MAC", "MAD", "MAE", "MAN", "MAO", "MAP", "MAT", "MAW", "MAY", +"ME", "MEG", "MEL", "MEN", "MET", "MEW", "MID", "MIN", "MIT", "MOB", +"MOD", "MOE", "MOO", "MOP", "MOS", "MOT", "MOW", "MUD", "MUG", "MUM", +"MY", "NAB", "NAG", "NAN", "NAP", "NAT", "NAY", "NE", "NED", "NEE", +"NET", "NEW", "NIB", "NIL", "NIP", "NIT", "NO", "NOB", "NOD", "NON", +"NOR", "NOT", "NOV", "NOW", "NU", "NUN", "NUT", "O", "OAF", "OAK", +"OAR", "OAT", "ODD", "ODE", "OF", "OFF", "OFT", "OH", "OIL", "OK", +"OLD", "ON", "ONE", "OR", "ORB", "ORE", "ORR", "OS", "OTT", "OUR", +"OUT", "OVA", "OW", "OWE", "OWL", "OWN", "OX", "PA", "PAD", "PAL", +"PAM", "PAN", "PAP", "PAR", "PAT", "PAW", "PAY", "PEA", "PEG", "PEN", +"PEP", "PER", "PET", "PEW", "PHI", "PI", "PIE", "PIN", "PIT", "PLY", +"PO", "POD", "POE", "POP", "POT", "POW", "PRO", "PRY", "PUB", "PUG", +"PUN", "PUP", "PUT", "QUO", "RAG", "RAM", "RAN", "RAP", "RAT", "RAW", +"RAY", "REB", "RED", "REP", "RET", "RIB", "RID", "RIG", "RIM", "RIO", +"RIP", "ROB", "ROD", "ROE", "RON", "ROT", "ROW", "ROY", "RUB", "RUE", +"RUG", "RUM", "RUN", "RYE", "SAC", "SAD", "SAG", "SAL", "SAM", "SAN", +"SAP", "SAT", "SAW", "SAY", "SEA", "SEC", "SEE", "SEN", "SET", "SEW", +"SHE", "SHY", "SIN", "SIP", "SIR", "SIS", "SIT", "SKI", "SKY", "SLY", +"SO", "SOB", "SOD", "SON", "SOP", "SOW", "SOY", "SPA", "SPY", "SUB", +"SUD", "SUE", "SUM", "SUN", "SUP", "TAB", "TAD", "TAG", "TAN", "TAP", +"TAR", "TEA", "TED", "TEE", "TEN", "THE", "THY", "TIC", "TIE", "TIM", +"TIN", "TIP", "TO", "TOE", "TOG", "TOM", "TON", "TOO", "TOP", "TOW", +"TOY", "TRY", "TUB", "TUG", "TUM", "TUN", "TWO", "UN", "UP", "US", +"USE", "VAN", "VAT", "VET", "VIE", "WAD", "WAG", "WAR", "WAS", "WAY", +"WE", "WEB", "WED", "WEE", "WET", "WHO", "WHY", "WIN", "WIT", "WOK", +"WON", "WOO", "WOW", "WRY", "WU", "YAM", "YAP", "YAW", "YE", "YEA", +"YES", "YET", "YOU", "ABED", "ABEL", "ABET", "ABLE", "ABUT", "ACHE", +"ACID", "ACME", "ACRE", "ACTA", "ACTS", "ADAM", "ADDS", "ADEN", "AFAR", +"AFRO", "AGEE", "AHEM", "AHOY", "AIDA", "AIDE", "AIDS", "AIRY", "AJAR", +"AKIN", "ALAN", "ALEC", "ALGA", "ALIA", "ALLY", "ALMA", "ALOE", "ALSO", +"ALTO", "ALUM", "ALVA", "AMEN", "AMES", "AMID", "AMMO", "AMOK", "AMOS", +"AMRA", "ANDY", "ANEW", "ANNA", "ANNE", "ANTE", "ANTI", "AQUA", "ARAB", +"ARCH", "AREA", "ARGO", "ARID", "ARMY", "ARTS", "ARTY", "ASIA", "ASKS", +"ATOM", "AUNT", "AURA", "AUTO", "AVER", "AVID", "AVIS", "AVON", "AVOW", +"AWAY", "AWRY", "BABE", "BABY", "BACH", "BACK", "BADE", "BAIL", "BAIT", +"BAKE", "BALD", "BALE", "BALI", "BALK", "BALL", "BALM", "BAND", "BANE", +"BANG", "BANK", "BARB", "BARD", "BARE", "BARK", "BARN", "BARR", "BASE", +"BASH", "BASK", "BASS", "BATE", "BATH", "BAWD", "BAWL", "BEAD", "BEAK", +"BEAM", "BEAN", "BEAR", "BEAT", "BEAU", "BECK", "BEEF", "BEEN", "BEER", + + + +McDonald [Page 5] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +"BEET", "BELA", "BELL", "BELT", "BEND", "BENT", "BERG", "BERN", "BERT", +"BESS", "BEST", "BETA", "BETH", "BHOY", "BIAS", "BIDE", "BIEN", "BILE", +"BILK", "BILL", "BIND", "BING", "BIRD", "BITE", "BITS", "BLAB", "BLAT", +"BLED", "BLEW", "BLOB", "BLOC", "BLOT", "BLOW", "BLUE", "BLUM", "BLUR", +"BOAR", "BOAT", "BOCA", "BOCK", "BODE", "BODY", "BOGY", "BOHR", "BOIL", +"BOLD", "BOLO", "BOLT", "BOMB", "BONA", "BOND", "BONE", "BONG", "BONN", +"BONY", "BOOK", "BOOM", "BOON", "BOOT", "BORE", "BORG", "BORN", "BOSE", +"BOSS", "BOTH", "BOUT", "BOWL", "BOYD", "BRAD", "BRAE", "BRAG", "BRAN", +"BRAY", "BRED", "BREW", "BRIG", "BRIM", "BROW", "BUCK", "BUDD", "BUFF", +"BULB", "BULK", "BULL", "BUNK", "BUNT", "BUOY", "BURG", "BURL", "BURN", +"BURR", "BURT", "BURY", "BUSH", "BUSS", "BUST", "BUSY", "BYTE", "CADY", +"CAFE", "CAGE", "CAIN", "CAKE", "CALF", "CALL", "CALM", "CAME", "CANE", +"CANT", "CARD", "CARE", "CARL", "CARR", "CART", "CASE", "CASH", "CASK", +"CAST", "CAVE", "CEIL", "CELL", "CENT", "CERN", "CHAD", "CHAR", "CHAT", +"CHAW", "CHEF", "CHEN", "CHEW", "CHIC", "CHIN", "CHOU", "CHOW", "CHUB", +"CHUG", "CHUM", "CITE", "CITY", "CLAD", "CLAM", "CLAN", "CLAW", "CLAY", +"CLOD", "CLOG", "CLOT", "CLUB", "CLUE", "COAL", "COAT", "COCA", "COCK", +"COCO", "CODA", "CODE", "CODY", "COED", "COIL", "COIN", "COKE", "COLA", +"COLD", "COLT", "COMA", "COMB", "COME", "COOK", "COOL", "COON", "COOT", +"CORD", "CORE", "CORK", "CORN", "COST", "COVE", "COWL", "CRAB", "CRAG", +"CRAM", "CRAY", "CREW", "CRIB", "CROW", "CRUD", "CUBA", "CUBE", "CUFF", +"CULL", "CULT", "CUNY", "CURB", "CURD", "CURE", "CURL", "CURT", "CUTS", +"DADE", "DALE", "DAME", "DANA", "DANE", "DANG", "DANK", "DARE", "DARK", +"DARN", "DART", "DASH", "DATA", "DATE", "DAVE", "DAVY", "DAWN", "DAYS", +"DEAD", "DEAF", "DEAL", "DEAN", "DEAR", "DEBT", "DECK", "DEED", "DEEM", +"DEER", "DEFT", "DEFY", "DELL", "DENT", "DENY", "DESK", "DIAL", "DICE", +"DIED", "DIET", "DIME", "DINE", "DING", "DINT", "DIRE", "DIRT", "DISC", +"DISH", "DISK", "DIVE", "DOCK", "DOES", "DOLE", "DOLL", "DOLT", "DOME", +"DONE", "DOOM", "DOOR", "DORA", "DOSE", "DOTE", "DOUG", "DOUR", "DOVE", +"DOWN", "DRAB", "DRAG", "DRAM", "DRAW", "DREW", "DRUB", "DRUG", "DRUM", +"DUAL", "DUCK", "DUCT", "DUEL", "DUET", "DUKE", "DULL", "DUMB", "DUNE", +"DUNK", "DUSK", "DUST", "DUTY", "EACH", "EARL", "EARN", "EASE", "EAST", +"EASY", "EBEN", "ECHO", "EDDY", "EDEN", "EDGE", "EDGY", "EDIT", "EDNA", +"EGAN", "ELAN", "ELBA", "ELLA", "ELSE", "EMIL", "EMIT", "EMMA", "ENDS", +"ERIC", "EROS", "EVEN", "EVER", "EVIL", "EYED", "FACE", "FACT", "FADE", +"FAIL", "FAIN", "FAIR", "FAKE", "FALL", "FAME", "FANG", "FARM", "FAST", +"FATE", "FAWN", "FEAR", "FEAT", "FEED", "FEEL", "FEET", "FELL", "FELT", +"FEND", "FERN", "FEST", "FEUD", "FIEF", "FIGS", "FILE", "FILL", "FILM", +"FIND", "FINE", "FINK", "FIRE", "FIRM", "FISH", "FISK", "FIST", "FITS", +"FIVE", "FLAG", "FLAK", "FLAM", "FLAT", "FLAW", "FLEA", "FLED", "FLEW", +"FLIT", "FLOC", "FLOG", "FLOW", "FLUB", "FLUE", "FOAL", "FOAM", "FOGY", +"FOIL", "FOLD", "FOLK", "FOND", "FONT", "FOOD", "FOOL", "FOOT", "FORD", +"FORE", "FORK", "FORM", "FORT", "FOSS", "FOUL", "FOUR", "FOWL", "FRAU", +"FRAY", "FRED", "FREE", "FRET", "FREY", "FROG", "FROM", "FUEL", "FULL", +"FUME", "FUND", "FUNK", "FURY", "FUSE", "FUSS", "GAFF", "GAGE", "GAIL", +"GAIN", "GAIT", "GALA", "GALE", "GALL", "GALT", "GAME", "GANG", "GARB", +"GARY", "GASH", "GATE", "GAUL", "GAUR", "GAVE", "GAWK", "GEAR", "GELD", +"GENE", "GENT", "GERM", "GETS", "GIBE", "GIFT", "GILD", "GILL", "GILT", + + + +McDonald [Page 6] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +"GINA", "GIRD", "GIRL", "GIST", "GIVE", "GLAD", "GLEE", "GLEN", "GLIB", +"GLOB", "GLOM", "GLOW", "GLUE", "GLUM", "GLUT", "GOAD", "GOAL", "GOAT", +"GOER", "GOES", "GOLD", "GOLF", "GONE", "GONG", "GOOD", "GOOF", "GORE", +"GORY", "GOSH", "GOUT", "GOWN", "GRAB", "GRAD", "GRAY", "GREG", "GREW", +"GREY", "GRID", "GRIM", "GRIN", "GRIT", "GROW", "GRUB", "GULF", "GULL", +"GUNK", "GURU", "GUSH", "GUST", "GWEN", "GWYN", "HAAG", "HAAS", "HACK", +"HAIL", "HAIR", "HALE", "HALF", "HALL", "HALO", "HALT", "HAND", "HANG", +"HANK", "HANS", "HARD", "HARK", "HARM", "HART", "HASH", "HAST", "HATE", +"HATH", "HAUL", "HAVE", "HAWK", "HAYS", "HEAD", "HEAL", "HEAR", "HEAT", +"HEBE", "HECK", "HEED", "HEEL", "HEFT", "HELD", "HELL", "HELM", "HERB", +"HERD", "HERE", "HERO", "HERS", "HESS", "HEWN", "HICK", "HIDE", "HIGH", +"HIKE", "HILL", "HILT", "HIND", "HINT", "HIRE", "HISS", "HIVE", "HOBO", +"HOCK", "HOFF", "HOLD", "HOLE", "HOLM", "HOLT", "HOME", "HONE", "HONK", +"HOOD", "HOOF", "HOOK", "HOOT", "HORN", "HOSE", "HOST", "HOUR", "HOVE", +"HOWE", "HOWL", "HOYT", "HUCK", "HUED", "HUFF", "HUGE", "HUGH", "HUGO", +"HULK", "HULL", "HUNK", "HUNT", "HURD", "HURL", "HURT", "HUSH", "HYDE", +"HYMN", "IBIS", "ICON", "IDEA", "IDLE", "IFFY", "INCA", "INCH", "INTO", +"IONS", "IOTA", "IOWA", "IRIS", "IRMA", "IRON", "ISLE", "ITCH", "ITEM", +"IVAN", "JACK", "JADE", "JAIL", "JAKE", "JANE", "JAVA", "JEAN", "JEFF", +"JERK", "JESS", "JEST", "JIBE", "JILL", "JILT", "JIVE", "JOAN", "JOBS", +"JOCK", "JOEL", "JOEY", "JOHN", "JOIN", "JOKE", "JOLT", "JOVE", "JUDD", +"JUDE", "JUDO", "JUDY", "JUJU", "JUKE", "JULY", "JUNE", "JUNK", "JUNO", +"JURY", "JUST", "JUTE", "KAHN", "KALE", "KANE", "KANT", "KARL", "KATE", +"KEEL", "KEEN", "KENO", "KENT", "KERN", "KERR", "KEYS", "KICK", "KILL", +"KIND", "KING", "KIRK", "KISS", "KITE", "KLAN", "KNEE", "KNEW", "KNIT", +"KNOB", "KNOT", "KNOW", "KOCH", "KONG", "KUDO", "KURD", "KURT", "KYLE", +"LACE", "LACK", "LACY", "LADY", "LAID", "LAIN", "LAIR", "LAKE", "LAMB", +"LAME", "LAND", "LANE", "LANG", "LARD", "LARK", "LASS", "LAST", "LATE", +"LAUD", "LAVA", "LAWN", "LAWS", "LAYS", "LEAD", "LEAF", "LEAK", "LEAN", +"LEAR", "LEEK", "LEER", "LEFT", "LEND", "LENS", "LENT", "LEON", "LESK", +"LESS", "LEST", "LETS", "LIAR", "LICE", "LICK", "LIED", "LIEN", "LIES", +"LIEU", "LIFE", "LIFT", "LIKE", "LILA", "LILT", "LILY", "LIMA", "LIMB", +"LIME", "LIND", "LINE", "LINK", "LINT", "LION", "LISA", "LIST", "LIVE", +"LOAD", "LOAF", "LOAM", "LOAN", "LOCK", "LOFT", "LOGE", "LOIS", "LOLA", +"LONE", "LONG", "LOOK", "LOON", "LOOT", "LORD", "LORE", "LOSE", "LOSS", +"LOST", "LOUD", "LOVE", "LOWE", "LUCK", "LUCY", "LUGE", "LUKE", "LULU", +"LUND", "LUNG", "LURA", "LURE", "LURK", "LUSH", "LUST", "LYLE", "LYNN", +"LYON", "LYRA", "MACE", "MADE", "MAGI", "MAID", "MAIL", "MAIN", "MAKE", +"MALE", "MALI", "MALL", "MALT", "MANA", "MANN", "MANY", "MARC", "MARE", +"MARK", "MARS", "MART", "MARY", "MASH", "MASK", "MASS", "MAST", "MATE", +"MATH", "MAUL", "MAYO", "MEAD", "MEAL", "MEAN", "MEAT", "MEEK", "MEET", +"MELD", "MELT", "MEMO", "MEND", "MENU", "MERT", "MESH", "MESS", "MICE", +"MIKE", "MILD", "MILE", "MILK", "MILL", "MILT", "MIMI", "MIND", "MINE", +"MINI", "MINK", "MINT", "MIRE", "MISS", "MIST", "MITE", "MITT", "MOAN", +"MOAT", "MOCK", "MODE", "MOLD", "MOLE", "MOLL", "MOLT", "MONA", "MONK", +"MONT", "MOOD", "MOON", "MOOR", "MOOT", "MORE", "MORN", "MORT", "MOSS", +"MOST", "MOTH", "MOVE", "MUCH", "MUCK", "MUDD", "MUFF", "MULE", "MULL", +"MURK", "MUSH", "MUST", "MUTE", "MUTT", "MYRA", "MYTH", "NAGY", "NAIL", + + + +McDonald [Page 7] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +"NAIR", "NAME", "NARY", "NASH", "NAVE", "NAVY", "NEAL", "NEAR", "NEAT", +"NECK", "NEED", "NEIL", "NELL", "NEON", "NERO", "NESS", "NEST", "NEWS", +"NEWT", "NIBS", "NICE", "NICK", "NILE", "NINA", "NINE", "NOAH", "NODE", +"NOEL", "NOLL", "NONE", "NOOK", "NOON", "NORM", "NOSE", "NOTE", "NOUN", +"NOVA", "NUDE", "NULL", "NUMB", "OATH", "OBEY", "OBOE", "ODIN", "OHIO", +"OILY", "OINT", "OKAY", "OLAF", "OLDY", "OLGA", "OLIN", "OMAN", "OMEN", +"OMIT", "ONCE", "ONES", "ONLY", "ONTO", "ONUS", "ORAL", "ORGY", "OSLO", +"OTIS", "OTTO", "OUCH", "OUST", "OUTS", "OVAL", "OVEN", "OVER", "OWLY", +"OWNS", "QUAD", "QUIT", "QUOD", "RACE", "RACK", "RACY", "RAFT", "RAGE", +"RAID", "RAIL", "RAIN", "RAKE", "RANK", "RANT", "RARE", "RASH", "RATE", +"RAVE", "RAYS", "READ", "REAL", "REAM", "REAR", "RECK", "REED", "REEF", +"REEK", "REEL", "REID", "REIN", "RENA", "REND", "RENT", "REST", "RICE", +"RICH", "RICK", "RIDE", "RIFT", "RILL", "RIME", "RING", "RINK", "RISE", +"RISK", "RITE", "ROAD", "ROAM", "ROAR", "ROBE", "ROCK", "RODE", "ROIL", +"ROLL", "ROME", "ROOD", "ROOF", "ROOK", "ROOM", "ROOT", "ROSA", "ROSE", +"ROSS", "ROSY", "ROTH", "ROUT", "ROVE", "ROWE", "ROWS", "RUBE", "RUBY", +"RUDE", "RUDY", "RUIN", "RULE", "RUNG", "RUNS", "RUNT", "RUSE", "RUSH", +"RUSK", "RUSS", "RUST", "RUTH", "SACK", "SAFE", "SAGE", "SAID", "SAIL", +"SALE", "SALK", "SALT", "SAME", "SAND", "SANE", "SANG", "SANK", "SARA", +"SAUL", "SAVE", "SAYS", "SCAN", "SCAR", "SCAT", "SCOT", "SEAL", "SEAM", +"SEAR", "SEAT", "SEED", "SEEK", "SEEM", "SEEN", "SEES", "SELF", "SELL", +"SEND", "SENT", "SETS", "SEWN", "SHAG", "SHAM", "SHAW", "SHAY", "SHED", +"SHIM", "SHIN", "SHOD", "SHOE", "SHOT", "SHOW", "SHUN", "SHUT", "SICK", +"SIDE", "SIFT", "SIGH", "SIGN", "SILK", "SILL", "SILO", "SILT", "SINE", +"SING", "SINK", "SIRE", "SITE", "SITS", "SITU", "SKAT", "SKEW", "SKID", +"SKIM", "SKIN", "SKIT", "SLAB", "SLAM", "SLAT", "SLAY", "SLED", "SLEW", +"SLID", "SLIM", "SLIT", "SLOB", "SLOG", "SLOT", "SLOW", "SLUG", "SLUM", +"SLUR", "SMOG", "SMUG", "SNAG", "SNOB", "SNOW", "SNUB", "SNUG", "SOAK", +"SOAR", "SOCK", "SODA", "SOFA", "SOFT", "SOIL", "SOLD", "SOME", "SONG", +"SOON", "SOOT", "SORE", "SORT", "SOUL", "SOUR", "SOWN", "STAB", "STAG", +"STAN", "STAR", "STAY", "STEM", "STEW", "STIR", "STOW", "STUB", "STUN", +"SUCH", "SUDS", "SUIT", "SULK", "SUMS", "SUNG", "SUNK", "SURE", "SURF", +"SWAB", "SWAG", "SWAM", "SWAN", "SWAT", "SWAY", "SWIM", "SWUM", "TACK", +"TACT", "TAIL", "TAKE", "TALE", "TALK", "TALL", "TANK", "TASK", "TATE", +"TAUT", "TEAL", "TEAM", "TEAR", "TECH", "TEEM", "TEEN", "TEET", "TELL", +"TEND", "TENT", "TERM", "TERN", "TESS", "TEST", "THAN", "THAT", "THEE", +"THEM", "THEN", "THEY", "THIN", "THIS", "THUD", "THUG", "TICK", "TIDE", +"TIDY", "TIED", "TIER", "TILE", "TILL", "TILT", "TIME", "TINA", "TINE", +"TINT", "TINY", "TIRE", "TOAD", "TOGO", "TOIL", "TOLD", "TOLL", "TONE", +"TONG", "TONY", "TOOK", "TOOL", "TOOT", "TORE", "TORN", "TOTE", "TOUR", +"TOUT", "TOWN", "TRAG", "TRAM", "TRAY", "TREE", "TREK", "TRIG", "TRIM", +"TRIO", "TROD", "TROT", "TROY", "TRUE", "TUBA", "TUBE", "TUCK", "TUFT", +"TUNA", "TUNE", "TUNG", "TURF", "TURN", "TUSK", "TWIG", "TWIN", "TWIT", +"ULAN", "UNIT", "URGE", "USED", "USER", "USES", "UTAH", "VAIL", "VAIN", +"VALE", "VARY", "VASE", "VAST", "VEAL", "VEDA", "VEIL", "VEIN", "VEND", +"VENT", "VERB", "VERY", "VETO", "VICE", "VIEW", "VINE", "VISE", "VOID", +"VOLT", "VOTE", "WACK", "WADE", "WAGE", "WAIL", "WAIT", "WAKE", "WALE", +"WALK", "WALL", "WALT", "WAND", "WANE", "WANG", "WANT", "WARD", "WARM", + + + +McDonald [Page 8] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +"WARN", "WART", "WASH", "WAST", "WATS", "WATT", "WAVE", "WAVY", "WAYS", +"WEAK", "WEAL", "WEAN", "WEAR", "WEED", "WEEK", "WEIR", "WELD", "WELL", +"WELT", "WENT", "WERE", "WERT", "WEST", "WHAM", "WHAT", "WHEE", "WHEN", +"WHET", "WHOA", "WHOM", "WICK", "WIFE", "WILD", "WILL", "WIND", "WINE", +"WING", "WINK", "WINO", "WIRE", "WISE", "WISH", "WITH", "WOLF", "WONT", +"WOOD", "WOOL", "WORD", "WORE", "WORK", "WORM", "WORN", "WOVE", "WRIT", +"WYNN", "YALE", "YANG", "YANK", "YARD", "YARN", "YAWL", "YAWN", "YEAH", +"YEAR", "YELL", "YOGA", "YOKE" +}; + +/* Encode 8 bytes in 'c' as a string of English words. + * Returns a pointer to a static buffer + */ +char * +btoe(engout,c) +char *c, *engout; +{ + char cp[9]; /* add in room for the parity 2 bits*/ + int p,i ; + + engout[0] = '\0'; + memcpy(cp, c,8); + /* compute parity */ + for(p = 0,i = 0; i < 64;i += 2) + p += extract(cp,i,2); + + cp[8] = (char)p << 6; + strncat(engout,&Wp[extract(cp, 0,11)][0],4); + strcat(engout," "); + strncat(engout,&Wp[extract(cp,11,11)][0],4); + strcat(engout," "); + strncat(engout,&Wp[extract(cp,22,11)][0],4); + strcat(engout," "); + strncat(engout,&Wp[extract(cp,33,11)][0],4); + strcat(engout," "); + strncat(engout,&Wp[extract(cp,44,11)][0],4); + strcat(engout," "); + strncat(engout,&Wp[extract(cp,55,11)][0],4); +#ifdef notdef + printf("engout is %s\n\r",engout); +#endif + return(engout); +} + +/* convert English to binary + * returns 1 OK - all good words and parity is OK + * 0 word not in data base + * -1 badly formed in put ie > 4 char word + + + +McDonald [Page 9] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + + * -2 words OK but parity is wrong + */ +int +etob(out, e) +char *out; +char *e; +{ + char *word; + int i, p, v,l, low,high; + char b[9]; + char input[36]; + + if(e == NULL) + return -1; + + strncpy(input,e,sizeof(input)); + memset(b, 0, sizeof(b)); + memset(out, 0, 8); + for(i=0,p=0;i<6;i++,p+=11){ + if((word = strtok(i == 0 ? input : NULL," ")) == NULL) + return -1; + l = strlen(word); + if(l > 4 || l < 1){ + return -1; + } else if(l < 4){ + low = 0; + high = 570; + } else { + low = 571; + high = 2047; + } + standard(word); + if( (v = wsrch(word,low,high)) < 0 ) + return 0; + insert(b,v,p,11); + } + + /* now check the parity of what we got */ + for(p = 0, i = 0; i < 64; i +=2) + p += extract(b, i, 2); + + if( (p & 3) != extract(b, 64,2) ) + return -2; + + memcpy(out,b,8); + + return 1; +} + + + +McDonald [Page 10] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +/* Display 8 bytes as a series of 16-bit hex digits */ +char * +put8(out,s) +char *out; +char *s; +{ + sprintf(out,"%02X%02X %02X%02X %02X%02X %02X%02X", + s[0] & 0xff,s[1] & 0xff,s[2] & 0xff, + s[3] & 0xff,s[4] & 0xff,s[5] & 0xff, + s[6] & 0xff,s[7] & 0xff); + return out; +} +#ifdef notdef +/* Encode 8 bytes in 'cp' as stream of ascii letters. + * Provided as a possible alternative to btoe() + */ +char * +btoc(cp) +char *cp; +{ + int i; + static char out[31]; + + /* code out put by characters 6 bits each added to 0x21 (!)*/ + for(i=0;i <= 10;i++){ + /* last one is only 4 bits not 6*/ + out[i] = '!'+ extract(cp,6*i,i >= 10 ? 4:6); + } + out[i] = '\0'; + return(out); +} +#endif + +/* Internal subroutines for word encoding/decoding */ + +/* Dictionary binary search */ +static int +wsrch(w,low,high) +char *w; +int low, high; +{ + int i,j; + + for(;;){ + i = (low + high)/2; + if((j = strncmp(w,Wp[i],4)) == 0) + return i; /* Found it */ + if(high == low+1){ + + + +McDonald [Page 11] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + + /* Avoid effects of integer truncation in /2 */ + if(strncmp(w,Wp[high],4) == 0) + return high; + else + return -1; + } + if(low >= high) + return -1; + /* I don't *think* this can happen...*/ + if(j < 0) + high = i; /* Search lower half */ + else + low = i; /* Search upper half */ + } +} +static void +insert(s, x, start, length) +char *s; +int x; +int start, length; +{ + unsigned char cl; + unsigned char cc; + unsigned char cr; + unsigned long y; + int shift; + + assert(length <= 11); + assert(start >= 0); + assert(length >= 0); + assert(start +length <= 66); + + shift = ((8 -(( start + length) % 8))%8); + y = (long) x << shift; + cl = (y >> 16) & 0xff; + cc = (y >> 8) & 0xff; + cr = y & 0xff; + if(shift + length > 16){ + s[start /8] |= cl; + s[start/8 +1] |= cc; + s[start/8 +2] |= cr; + } else if(shift +length > 8){ + s[start/8] |= cc; + s[start/8 + 1] |= cr; + } else { + s[start/8] |= cr; + } +} + + + +McDonald [Page 12] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +static void +standard(word) +register char *word; +{ + while(*word){ + if(!isascii(*word)) + break; + if(islower(*word)) + *word = toupper(*word); + if(*word == '1') + *word = 'L'; + if(*word == '0') + *word = 'O'; + if(*word == '5') + *word = 'S'; + word++; + } +} + +/* Extract 'length' bits from the char array 's' + starting with bit 'start' */ +static unsigned long +extract(s, start, length) +char *s; +int start, length; +{ + unsigned char cl; + unsigned char cc; + unsigned char cr; + unsigned long x; + + assert(length <= 11); + assert(start >= 0); + assert(length >= 0); + assert(start +length <= 66); + + cl = s[start/8]; + cc = s[start/8 +1]; + cr = s[start/8 +2]; + x = ((long)(cl<<8 | cc) <<8 | cr) ; + x = x >> (24 - (length + (start %8))); + x =( x & (0xffff >> (16-length) ) ); + return(x); +} + + + + + + + +McDonald [Page 13] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +Appendix B - Source for 128-bit key to/from English words (convert.c) + +/* convert.c -- Wrapper to S/Key binary-to-English routines. + Daniel L. McDonald -- U. S. Naval Research Laboratory. */ + +#include <string.h> + +/* eng2key() assumes words must be separated by spaces only. + + eng2key() returns + + 1 if succeeded + 0 if word not in dictionary + -1 if badly formed string + -2 if words are okay but parity is wrong. + (see etob() in S/Key) +*/ + +int eng2key(keyout,eng) +char *keyout,*eng; +{ + int rc=0,state=1; + char *eng2; + + /* Find pointer to word 7. */ + + for (eng2 = eng; rc<7 && (*(++eng2) != '\0'); ) + if (*eng2 != ' ') + { + rc += state; + state = 0; + } + else state=1; + + if ( (rc = etob(keyout,eng)) != 1) + return rc; + + rc = etob(keyout+8,eng2); + + return rc; +} + +/* key2eng() assumes string referenced by + engout has at least 60 characters + (4*12 + 11 spaces + '\0') of space. + + key2eng() returns pointer to engout. + + + + +McDonald [Page 14] + +RFC 1751 Human-Readable 128-bit Keys December 1994 + + +*/ + +char *key2eng(engout,key) +char *engout,*key; +{ + btoe(engout,key); + strcat(engout," "); + btoe(engout+strlen(engout),key+8); + return engout; +} + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +McDonald [Page 15] + |