Examine individual changes

'<nowiki>-----</nowiki>BEGIN PGP PUBLIC KEY BLOCK----- mDMEZr6b6BYJKwYBBAHaRw8BAQdAYqxLBwo4cqR2Y8PrNog1TSV6C4O70nh3h5e6 IaEoME+0HkpvaG5zaSA8am9obnNpZGkwMDdAZ21haWwuY29tPohyBBMWCAAaBAsJ CAcCFQgCFgECGQEFgma+m+gCngECmwMACgkQizu/GpTT5pQ8AwD/Zs1m5TXbEtuP sWjsMWg0GJWf2TGyH28zg749tclTmogA/22xJQfYA4tpas2UXTU7VsgO4j2do2lt cfsHWqfeHi4DuDgEZr6b6BIKKwYBBAGXVQEFAQEHQOFtWNauMzTZPylO2Qsa6v54 rFqcaWu+1Z6DeeT/pwc1AwEIB4hhBBgWCAAJBYJmvpvoApsMAAoJEIs7vxqU0+aU 6r4A/0kHRyfAGzs5rxdo8LKw+k8Iv6Pk+dZ67TSWHd24+1IYAP4vndDzn2tSFs7/ kHEgpif/mYM63R1zKkxvJdvtc5PDAg== =XE44 <nowiki>-----</nowiki>END PGP PUBLIC KEY BLOCK----- ==History and structure== The PGP Word List was designed in 1995 by [[Patrick Juola]], a [[Computational linguistics|computational linguist]], and [[Philip Zimmermann]], creator of [[Pretty Good Privacy|PGP]].<ref name="Juola1996a">{{cite book |first1=Patrick |last1=Juola |first2=Philip |last2=Zimmermann |title=Proceeding of Fourth International Conference on Spoken Language Processing. ICSLP '96 |chapter=Whole-word phonetic distances and the PGPfone alphabet |chapter-url=http://www.mathcs.duq.edu/~juola/papers.d/icslp96.pdf |year=1996 |volume=1 |pages=98–101 |doi=10.1109/ICSLP.1996.607046 |isbn=0-7803-3555-4 |s2cid=10385500 }}</ref><ref name="Juola1996b">{{cite journal |first=Patrick |last=Juola |url=http://www.mathcs.duq.edu/~juola/papers.d/pgpfonenemlap.ps |title=Isolated Word Confusion Metrics and the PGPfone Alphabet |year=1996 |publisher=Oxford University, Dept. of Experimental Psychology |journal=Proceedings of New Methods in Language Processing 2 |location=Ankara, Turkey|arxiv=cmp-lg/9608021 |bibcode=1996cmp.lg....8021J }}</ref> The words were carefully chosen for their [[phonetic]] distinctiveness, using [[genetic algorithms]] to select lists of words that had optimum separations in [[phoneme]] space. The candidate word lists were randomly drawn from [[Grady Ward]]'s [[Moby Project|Moby Pronunciator]] list as raw material for the search, successively refined by the genetic algorithms. The automated search converged to an optimized solution in about 40 hours on a [[DEC Alpha]], a particularly fast machine in that era. The Zimmermann–Juola list was originally designed to be used in [[PGPfone]], a secure VoIP application, to allow the two parties to verbally compare a short authentication string to detect a [[man-in-the-middle attack]] (MiTM). It was called a [[biometric]] word list because the authentication depended on the two human users recognizing each other's distinct voices as they read and compared the words over the voice channel, binding the identity of the speaker with the words, which helped protect against the MiTM attack. The list can be used in many other situations where a biometric binding of identity is not needed, so calling it a biometric word list may be imprecise. Later, it was used in [[Pretty Good Privacy|PGP]] to compare and verify PGP [[public key]] [[message digest|fingerprints]] over a voice channel. This is known in PGP applications as the "biometric" representation. When it was applied to PGP, the list of words was further refined, with contributions by [[Jon Callas]]. More recently, it has been used in [[Zfone]] and the [[ZRTP]] protocol, the successor to PGPfone. The list is actually composed of two lists, each containing 256 [[phonetics|phonetically]] distinct words, in which each word represents a different byte value between 0 and 255. Two lists are used because reading aloud long random sequences of human words usually risks three kinds of errors: 1) transposition of two consecutive words, 2) duplicate words, or 3) omitted words. To detect all three kinds of errors, the two lists are used alternately for the even-offset bytes and the odd-offset bytes in the byte sequence. Each byte value is actually represented by two different words, depending on whether that byte appears at an even or an odd offset from the beginning of the byte sequence. The two lists are readily distinguished by the number of [[syllables]]; the even list has words of two syllables, the odd list has three. The two lists have a maximum word length of 9 and 11 letters, respectively. Using a two-list scheme was suggested by Zhahai Stewart. == Word lists == Here are the two lists of words as presented in the PGPfone Owner's Manual.<ref>{{cite web |url=http://web.mit.edu/network/pgpfone/manual/index.html#PGP000062 |title=Archived copy |website=web.mit.edu |access-date=12 January 2022 |archive-url=https://web.archive.org/web/20100326141145/http://web.mit.edu/network/pgpfone/manual/index.html#PGP000062 |archive-date=26 March 2010 |url-status=dead}}</ref> {| class="wikitable" style="float: left;" ! Hex!!align=left|Even Word!!align=left|Odd Word |- |00||aardvark||adroitness |- |01||absurd||adviser |- |02||accrue||aftermath |- |03||acme||aggregate |- |04||adrift||alkali |- |05||adult||almighty |- |06||afflict||amulet |- |07||ahead||amusement |- |08||aimless||antenna |- |09||Algol||applicant |- |0A||allow||Apollo |- |0B||alone||armistice |- |0C||ammo||article |- |0D||ancient||asteroid |- |0E||apple||Atlantic |- |0F||artist||atmosphere |- |10||assume||autopsy |- |11||Athens||Babylon |- |12||atlas||backwater |- |13||Aztec||barbecue |- |14||baboon||belowground |- |15||backfield||bifocals |- |16||backward||bodyguard |- |17||banjo||bookseller |- |18||beaming||borderline |- |19||bedlamp||bottomless |- |1A||beehive||Bradbury |- |1B||beeswax||bravado |- |1C||befriend||Brazilian |- |1D||Belfast||breakaway |- |1E||berserk||Burlington |- |1F||billiard||businessman |- |20||bison||butterfat |- |21||blackjack||Camelot |- |22||blockade||candidate |- |23||blowtorch||cannonball |- |24||bluebird||Capricorn |- |25||bombast||caravan |- |26||bookshelf||caretaker |- |27||brackish||celebrate |- |28||breadline||cellulose |- |29||breakup||certify |- |2A||brickyard||chambermaid |- |2B||briefcase||Cherokee |- |2C||Burbank||Chicago |- |2D||button||clergyman |- |2E||buzzard||coherence |- |2F||cement||combustion |- |30||chairlift||commando |- |31||chatter||company |- |32||checkup||component |- |33||chisel||concurrent |- |34||choking||confidence |- |35||chopper||conformist |- |36||Christmas||congregate |- |37||clamshell||consensus |- |38||classic||consulting |- |39||classroom||corporate |- |3A||cleanup||corrosion |- |3B||clockwork||councilman |- |3C||cobra||crossover |- |3D||commence||crucifix |- |3E||concert||cumbersome |- |3F||cowbell||customer |} {| class="wikitable" style="float: left;" ! Hex!!align=left|Even Word!!align=left|Odd Word |- |40||crackdown||Dakota |- |41||cranky||decadence |- |42||crowfoot||December |- |43||crucial||decimal |- |44||crumpled||designing |- |45||crusade||detector |- |46||cubic||detergent |- |47||dashboard||determine |- |48||deadbolt||dictator |- |49||deckhand||dinosaur |- |4A||dogsled||direction |- |4B||dragnet||disable |- |4C||drainage||disbelief |- |4D||dreadful||disruptive |- |4E||drifter||distortion |- |4F||dropper||document |- |50||drumbeat||embezzle |- |51||drunken||enchanting |- |52||Dupont||enrollment |- |53||dwelling||enterprise |- |54||eating||equation |- |55||edict||equipment |- |56||egghead||escapade |- |57||eightball||Eskimo |- |58||endorse||everyday |- |59||endow||examine |- |5A||enlist||existence |- |5B||erase||exodus |- |5C||escape||fascinate |- |5D||exceed||filament |- |5E||eyeglass||finicky |- |5F||eyetooth||forever |- |60||facial||fortitude |- |61||fallout||frequency |- |62||flagpole||gadgetry |- |63||flatfoot||Galveston |- |64||flytrap||getaway |- |65||fracture||glossary |- |66||framework||gossamer |- |67||freedom||graduate |- |68||frighten||gravity |- |69||gazelle||guitarist |- |6A||Geiger||hamburger |- |6B||glitter||Hamilton |- |6C||glucose||handiwork |- |6D||goggles||hazardous |- |6E||goldfish||headwaters |- |6F||gremlin||hemisphere |- |70||guidance||hesitate |- |71||hamlet||hideaway |- |72||highchair||holiness |- |73||hockey||hurricane |- |74||indoors||hydraulic |- |75||indulge||impartial |- |76||inverse||impetus |- |77||involve||inception |- |78||island||indigo |- |79||jawbone||inertia |- |7A||keyboard||infancy |- |7B||kickoff||inferno |- |7C||kiwi||informant |- |7D||klaxon||insincere |- |7E||locale||insurgent |- |7F||lockup||integrate |} {| class="wikitable" style="float: left;" ! Hex!!align=left|Even Word!!align=left|Odd Word |- |80||merit||intention |- |81||minnow||inventive |- |82||miser||Istanbul |- |83||Mohawk||Jamaica |- |84||mural||Jupiter |- |85||music||leprosy |- |86||necklace||letterhead |- |87||Neptune||liberty |- |88||newborn||maritime |- |89||nightbird||matchmaker |- |8A||Oakland||maverick |- |8B||obtuse||Medusa |- |8C||offload||megaton |- |8D||optic||microscope |- |8E||orca||microwave |- |8F||payday||midsummer |- |90||peachy||millionaire |- |91||pheasant||miracle |- |92||physique||misnomer |- |93||playhouse||molasses |- |94||Pluto||molecule |- |95||preclude||Montana |- |96||prefer||monument |- |97||preshrunk||mosquito |- |98||printer||narrative |- |99||prowler||nebula |- |9A||pupil||newsletter |- |9B||puppy||Norwegian |- |9C||python||October |- |9D||quadrant||Ohio |- |9E||quiver||onlooker |- |9F||quota||opulent |- |A0||ragtime||Orlando |- |A1||ratchet||outfielder |- |A2||rebirth||Pacific |- |A3||reform||pandemic |- |A4||regain||Pandora |- |A5||reindeer||paperweight |- |A6||rematch||paragon |- |A7||repay||paragraph |- |A8||retouch||paramount |- |A9||revenge||passenger |- |AA||reward||pedigree |- |AB||rhythm||Pegasus |- |AC||ribcage||penetrate |- |AD||ringbolt||perceptive |- |AE||robust||performance |- |AF||rocker||pharmacy |- |B0||ruffled||phonetic |- |B1||sailboat||photograph |- |B2||sawdust||pioneer |- |B3||scallion||pocketful |- |B4||scenic||politeness |- |B5||scorecard||positive |- |B6||Scotland||potato |- |B7||seabird||processor |- |B8||select||provincial |- |B9||sentence||proximate |- |BA||shadow||puberty |- |BB||shamrock||publisher |- |BC||showgirl||pyramid |- |BD||skullcap||quantity |- |BE||skydive||racketeer |- |BF||slingshot||rebellion |} {| class="wikitable" style="float: left;" ! Hex!!align=left|Even Word!!align=left|Odd Word |- |C0||slowdown||recipe |- |C1||snapline||recover |- |C2||snapshot||repellent |- |C3||snowcap||replica |- |C4||snowslide||reproduce |- |C5||solo||resistor |- |C6||southward||responsive |- |C7||soybean||retraction |- |C8||spaniel||retrieval |- |C9||spearhead||retrospect |- |CA||spellbind||revenue |- |CB||spheroid||revival |- |CC||spigot||revolver |- |CD||spindle||sandalwood |- |CE||spyglass||sardonic |- |CF||stagehand||Saturday |- |D0||stagnate||savagery |- |D1||stairway||scavenger |- |D2||standard||sensation |- |D3||stapler||sociable |- |D4||steamship||souvenir |- |D5||sterling||specialist |- |D6||stockman||speculate |- |D7||stopwatch||stethoscope |- |D8||stormy||stupendous |- |D9||sugar||supportive |- |DA||surmount||surrender |- |DB||suspense||suspicious |- |DC||sweatband||sympathy |- |DD||swelter||tambourine |- |DE||tactics||telephone |- |DF||talon||therapist |- |E0||tapeworm||tobacco |- |E1||tempest||tolerance |- |E2||tiger||tomorrow |- |E3||tissue||torpedo |- |E4||tonic||tradition |- |E5||topmost||travesty |- |E6||tracker||trombonist |- |E7||transit||truncated |- |E8||trauma||typewriter |- |E9||treadmill||ultimate |- |EA||Trojan||undaunted |- |EB||trouble||underfoot |- |EC||tumor||unicorn |- |ED||tunnel||unify |- |EE||tycoon||universe |- |EF||uncut||unravel |- |F0||unearth||upcoming |- |F1||unwind||vacancy |- |F2||uproot||vagabond |- |F3||upset||vertigo |- |F4||upshot||Virginia |- |F5||vapor||visitor |- |F6||village||vocalist |- |F7||virus||voyager |- |F8||Vulcan||warranty |- |F9||waffle||Waterloo |- |FA||wallet||whimsical |- |FB||watchword||Wichita |- |FC||wayside||Wilmington |- |FD||willow||Wyoming |- |FE||woodlark||yesteryear |- |FF||Zulu||{{not a typo|Yucatan}} |} {{clear}} ==Examples== Each byte in a bytestring is encoded as a single word. A sequence of bytes is rendered in [[network byte order]], from left to right. For example, the leftmost (i.e. byte 0) is considered "even" and is encoded using the PGP Even Word table. The next byte to the right (i.e. byte 1) is considered "odd" and is encoded using the PGP Odd Word table. This process repeats until all bytes are encoded. Thus, "E582" produces "topmost Istanbul", whereas "82E5" produces "miser travesty". A PGP public key fingerprint that displayed in [[hexadecimal]] as :<code>E582</code> <code>94F2</code> <code>E9A2</code> <code>2748</code> <code>6E8B</code> :<code>061B</code> <code>31CC</code> <code>528F</code> <code>D7FA</code> <code>3F19</code> would display in PGP Words (the "biometric" fingerprint) as :<code>topmost Istanbul</code> <code>Pluto vagabond</code> <code>treadmill Pacific</code> <code>brackish dictator</code> <code>goldfish Medusa</code> :<code>afflict bravado</code> <code>chatter revolver</code> <code>Dupont midsummer</code> <code>stopwatch whimsical</code> <code>cowbell bottomless</code> The order of bytes in a bytestring depends on [[endianness]]. == Other word lists for data == There are several other word lists for conveying data in a clear unambiguous way via a voice channel: * the [[NATO phonetic alphabet]] maps individual letters and digits to individual words * the [[S/KEY]] system maps 64 bit numbers to 6 short words of 1 to 4 characters each from a publicly accessible 2048-word dictionary. The same dictionary is used in RFC 1760 and RFC 2289. * the [[Diceware]] system maps five base-6 random digits (almost 13 bits of entropy) to a word from a dictionary of 7,776 distinct words. ** the [[Electronic Frontier Foundation]] has published a set of improved word lists based on the same concept<ref>{{Cite web|url=https://www.eff.org/deeplinks/2016/07/new-wordlists-random-passphrases|title = EFF's New Wordlists for Random Passphrases|date = 19 July 2016}}</ref> * FIPS 181: [[Automated Password Generator]] converts random numbers into somewhat pronounceable "words". * mnemonic encoding converts 32 bits of data into 3 words from a vocabulary of 1626 words.<ref>[http://www.tothink.com/mnemonic/ mnemonic encoding] {{webarchive|url=https://web.archive.org/web/20080302025836/http://www.tothink.com/mnemonic/ |date=2008-03-02 }} and [https://github.com/singpolyma/mnemonicode updated code]</ref> * [[what3words]] encodes geographic coordinates in 3 dictionary words. * the BIP39 standard permits encoding a cryptographic key of fixed size (128 or 256 bits, usually the unencrypted master key of a [[Cryptocurrency wallet]]) into a short sequence of readable words known as the [[seed phrase]], for the purpose of storing the key offline. This is used in cryptocurrencies such as [[Bitcoin]] or [[Monero]]. * Like the PGP word list, the [https://developer.blockchaincommons.com/bytewords/ Bytewords] standard maps each possible byte to a word. There is only one list, rather than two. The words are uniformly four letters long and can be uniquely identified by their first and last letters ==References== :''This article incorporates material that is copyrighted by PGP Corporation and has been licensed under the GNU Free Documentation License. (per Jon Callas, CTO, CSO PGP Corporation, 4-Jan-2007)'' {{reflist}} [[Category:Spelling alphabets]] [[Category:Binary-to-text encoding formats]] [[Category:Military communications]] [[Category:Cryptography]] [[Category:OpenPGP]]'