A question long on my mind is if the Zodiac picked up the idea of a sequential homophonic cipher from somewhere. I don’t know if it is mentioned in any of the books out there. A more general question, how long is the idea of a sequential homophonic cipher around? And why is it used? As far as I know the 408 and possibly the 340 are the only examples.
Though. A while ago I noticed that the W.B. Tyler 2 cipher looks like a sequential homophonic (cycle score) and that is a cipher from 1841! This cipher is known as a homophonic with polyalphabetism/errors mixed in and was solved by Gil Broza in 2000. I was able to solve this cipher automatically with AZdecrypt some years ago though it is very hard at a multiplicity of only 0.206.
I think it is worth taking a look at this cipher.
In 1841, Edgar Allan Poe wrote a series of articles in Graham’s Magazine, in which he solved simple ciphers sent by the reader. At the end of the series, Poe published two cryptograms sent by W. B. Tyler, who wanted to challenge Poe’s remark that human ingenuity could not contrive a cipher which human ingenuity cannot resolve.
Damn. This story is eerily similar to the ACA challenging Zodiac.
55 19 109 37 51 71 81 2 9 34 27 115 78 25 5 32 64 79 47 107 57 13 12 33 45 73 44 26 40 20 36 46 75 30 133 15 82 24 17 31 23 4 70 14 58 95 83 69 80 27 6 10 39 52 107 54 110 8 104 21 67 94 18 53 120 11 29 74 72 63 68 3 40 4 43 48 71 16 30 106 121 108 91 98 72 50 49 41 22 32 99 105 77 46 28 45 42 38 6 24 2 27 1 9 5 81 65 76 47 56 79 10 73 57 12 10 35 135 92 85 6 17 26 55 95 113 67 36 22 7 84 25 14 20 36 8 29 110 21 82 31 103 105 18 94 72 51 100 89 53 39 42 63 11 93 83 16 44 59 8 130 21 33 50 1 8 2 22 24 23 96 4 64 91 102 12 106 62 128 71 37 5 7 69 55 33 75 38 66 29 31 49 98 109 56 54 15 101 85 52 80 9 99 64 15 34 75 81 1 19 18 16 28 82 30 60 41 31 77 23 32 78 57 35 43 84 28 86 53 2 55 13 20 65 58 69 80 56 42 125 11 14 134 25 83 12 72 109 64 68 71 46 90 51 17 87 100 89 53 3 42 6 24 26 27 15 9 24 3 70 7 4 83 117 4 111 22 63 59 97 42 43 28 61 58 66 76 119 62 5 48 10 39 122 9 111 50 96 121 35 32 31 41 112 85 1 13 29 62 44 51 20 90 14 15 73 8 107 18 37 61 23 34 88 79 27 123 46 54 21 36 38 90 30 19 92 114 47 40 11 17 74 60 1 97 86 33 25 137 10 52 55 28 16 2 99 120 46 13 116 131 95 1 43 59 11 28 3 25 78 34 2 83 67 118 62 47 41 65 38 91 35 58 31 7 12 26 71 37 84 117 96 1 5 87 101 17 81 108 100 45 79 49 70 24 57 9 60 44 88 97 86 4 17 39 74 89 15 43 13 7 56 54 73 52 82 85 88 3 49 6 30 78 32 3 104 8 29 113 110 102 14 80 18 77 41 94 48 53 2 112 36 103 63 23 11 47 98 45 20 26 55 22 32 66 24 19 50 75 93 70 4 4 7 6 56 16 106 34 1 105 46 39 95 76 51 57 13 12 33 119 72 40 44 25 6 114 136 10 125 129 40 54 27 3 22 7 64 82 8 124 48 21 118 18 77 138 30 84 87 53 29 69 68 10 78 111 16 11 62 5 15 2 61 67 38 98 35 58 31 23 96 4 94 45 13 49 60 20 92 19 48 21 63 115 47 37 14 32 74 99 12 26 81 75 44 59 8 116 113 70 65 28 68 45 122 103 87 50 19 93 20 11 22 100 9 52 51 15 41 34 61 7 80 25 127 124 126 5 91 29 30 1 39 108 68 79 54 73 18 27 50 89 93 33 102 86 23 36 40 67 57 2 16 123 76 112 48 88 17 69 101 56 77 52 97 76 66 12 14 92 3 6 10 132 49 38 19 74 9 21 104 61 35 43 59 90 13 14 42 1 60 5 37 65 26 3 66
On my to do list is to try to make messages with one simple rule. Randomly select the symbol from the homophone group, except just don’t repeat the last homophone selected from that group. The rule wouldn’t apply to groups of only two homophones. I don’t know what to do with those. But groups of 3 maybe there will be enough cycling to get us to 340 scores, create L=17 or similar, and also high frequency symbols, ones that map to high frequency plaintext, that don’t cycle.
Here is a new AZdecrypt solve for the cipher and the resulting cipher to plain text cycles.
It is reported that there are about 2 dozen errors. But I counted about 30 after reviewing only a part of the solution. Probably 10% to 20% of the cipher is faulty causing a serious problem for decryption.
With so many errors not many of the cycles are intact but some are reasonably well preserved such as: y1dyk1dyk1dyk1dkyk1kdyk1dyk1dy. We have here a sequential homophonic cipher from 1841 or earlier that went unsolved for almost 160 years. I really wonder if the 340 could be the same. The earliest use of a sequential homophonic cipher I could find on the internet is the spanish strip cipher, dating back to 1936: https://www.emsec.ruhr-uni-bochum.de/me … enthin.pdf
ITWASEARLYSPRINGWARBANDSULT
RRGLOWINTHEAFTERNOONTHSVERY
BRMEMESSEEMEDTOSHARETHEDIFI
COOOSLANGONROSUOIVERSILNATU
REAELADENTHEVARIOUSLNDSINGL
EDMEHFINESOSTHEROSEANDTHERE
SSIERNETHEWOODFIREANDTISWIL
DFLOWERTHEYHLOWTYWAITEDSHII
AFRTGRANTSSNERINGTOTHEOPENW
INDOWWHEOESASTHEAOVERSTLEAR
DENCEINSHOOTSUOLUPINHERBLIS
HINGFACEINDITSGENTLEBEAUTYH
ASMORELIEITHERREATIIONSIVEY
ISDROMONCHOITHESAIRYRNSPIRA
TIONOFDDREASCHINSHAACTUALRE
ALITHONEARTHTTNDERLYHEHALVI
RGAMEDUMONHERASHERCLISTEROU
GRINGLETSWAREEDVEDFYINOROUS
ANDSPORTIVEREPURRSANDWHETHE
PERMISSEDTHERIDEINTRUSIONOF
THESUNLIGHTHESPRANGTODRAWTH
ECURTSHUBISSTAGENTLYSTAYUDH
ISTONODIIRCHARLESSHASONTLRS
ARDMUCHHATHERYOULDNHAVEALIT
TLEMUNTHENNOIINATRAL
¦xRa&4bCœˆ#zA<ƒV6=} ±y${G-
pcN+7«wQ.@?t°>*`£_‹M’eˆ‘D™¯
}^¨”"‡,r/ª)Š1OS!¤Jc*Z‰4dw[3
TLžSY§©…ƒ†u'7Ž{|²‘?ˆlC<b–€
=•6DG yDfWoX‘tp¦‹¢,+…khA£N+
”1¨‡@°Bu/rS&(Iª™|!ŠEMd-q”~‡
$Yl”…?>j*VLUy[¡‚4a<k’¦$«²8
1°§žR•^.vX¯eC†V.œ«blx/dŽ@wm
©°'>ƒz fZhŽ]ª¦±N–_’e•|sŠ£
AMySRV¤47Œ&tH(IªJ|‘?pˆ.C?J`
k*M;*“…!q„|ZŽ¥_8€š¡<‰D™¬C“Y
j3fƒ°©gXl±1¡-&NŒ£.G”}/a¥>œ5
6ˆK7^‡+²Œwxoi=cŠtOml„]$A—D¯
¦Žd†)7±0›‹lZqŠŽJAzœM,9¡=©
–²Lf_°kyp4ah;jl<HvtbT({6§`?
Cm-5„]*t™OI.Z±k•^G¯@X5J§‘w
zƒJ"”1¢¨U£e/'©r‰ªg+B!>Š=ž{
Np¦…ƒ8?xY«E`**k‘•d[œlu7™‹€&
±y$šSc-A‘i:DsFc^ˆJ…kV@”2‰‡
9/'PwhHª1’¤Dz“dŠ¡<.¥,²žf_°
>j*r{±§mNox‰‡!#=a£ƒO†ypb«-q
”0¢`–Ž¤{¬BHYxENŠ…(C¯&.©œ¥ke
A%2n<L1wl™T¤6^G/ˆYIE$U]>+c,
dK€g‰5t’v•'¯„€8y£oJ‘D®§²x
OC‡"¥fZqŒ±£|lm<a–pJ8
Output to input key:
--------------------------------------------------------
I: ¦Aww3²l¦ABl¡¦²lwm¦A“¡“3l¡²wmlA¦lA¡²lmwB¦lAw“¡²mBAwl²lm (0)
T: x-.>’OZ–W(->’..x>Z–’(.Z-.>xOZ–(-O.Z>x-2’.>xO-–x(.2>’xOZ– (0)
W: RV«V«RV«RV«V« (48)
A: ab6 tJ©b6 tEab© tJJ©a6tJ©atb6 tJJ©E JabE©6E tJ®aJ (0)
S: &ˆ$ˆ,r!YŽˆ,hr&!$Y$ŽhŽ&Hˆ!ŽY&ˆ$ŽŽ,hHr!Y&$ˆhH,r!ŽHY&%ˆY$, (0)
E: 4?*D”‡/ªŠ*4?•DDX”‡/ªŠ”‡”?*4•X/ª•Š4Œª??**DXŒ”/‡ŒiŠDŠ4?*•X”/ªŠ?**•iD”‡/ªDŠ*‡”Š/•D‡Œ (0)
R: z=pc`™^c'=p™~‚^'zp`™^=cz=p`™^z'=p`™c:c^'z=p`™^c'p (0)
L: CG+§CG++8§CC8CG+§CG§+8§CG+8§C8 (210)
Y: œ¯¯œœ¯œ¯œ¯œ¯ (144)
P: #sš9šs9# (8)
N: <±Q£M…u<f…£uM…<f]±£MM…<f±£]±Mf<]±£…u±…<f±£…<]£f±£< (0)
G: ƒNƒNƒNƒNƒNƒNƒN (312)
B: }}¬}¬ (12)
D: y1dyk1dyk1dyk1dkyk1kdyk1dyk1dy (1520)
U: {{€¢¥€¥{¢{€F¥{¢{¥€€¥ (10)
O: 7_‹SLžS†7|‹S|LUž†_|S7|„|_7„†7‹L_„Už7‹Sž_†nLU„| (0)
H: @e¤‰o@Iqjve@e¤Iq‰j5o›qjv5I@5e‰@‰¤jo‰q¤e¤I‰5voq (0)
F: °[°[°°°°[° (60)
V: ‘‘‘‘—‘‘‘‘ (4)
M: ¨")¨K)"¨PK" (10)
C: T;g0;Tg0Tg (48)
