ADFGVX cipher
- Description
The ADFGVX cipher was a manually applied field cipher used by the German Army during World War I. It was broken in 1918 by the French cryptanalyst Georges Painvin.
The workings of the cipher are described in the Wikipedia article, linked to above, and so will not be repeated here.
- Task
Write routines, functions etc. in your language to:
1. Encrypt suitable plaintext and decrypt the resulting cipher text using the ADFGVX cipher algorithm given a Polybius square (see 2. below) and a suitable key. For this purpose suitable means text consisting solely of ASCII upper case letters or digits.
2. Create a 6 x 6 Polybius square using a random combination of the letters A to Z and the digits 0 to 9 and then display it.
3. Given the number of letters (between 7 and 12 say) to use, create a key by selecting a suitable word at random from unixdict.txt and then display it. The word selected should be such that none of its characters are repeated.
Use these routines to create a Polybius square and a 9 letter key.
These should then be used to encrypt the plaintext: ATTACKAT1200AM and decrypt the resulting cipher text. Display here the results of both operations.
- Note
As it's unclear from the Wikipedia article how to handle a final row with fewer elements than the number of characters in the key, either of the methods mentioned in Columnar transposition may be used. In the case of the second method, it is also acceptable to fill any gaps after shuffling by moving elements to the left which makes decipherment harder.
F#
<lang fsharp> // ADFGVX cipher. Nigel Galloway: August 23rd., 2021 let polybus=let n=[|yield! {'A'..'Z'}; yield! {'0'..'9'}|] in MathNet.Numerics.Combinatorics.GeneratePermutation 36|>Array.map(fun g->n.[g]),[|'A';'D';'F';'G';'V';'X'|] let printPolybus(a,g)=printf " "; g|>Array.iter(printf "%c "); printfn ""; printfn " ----------------"
g|>Array.iteri(fun n g->printf " %c|" g; [0..5]|>List.iter(fun g->printf " %c " (Array.item(n*6+g) a)); printfn "")
let c2p n g=let g=(fst>>(Array.findIndex((=) g))) n in let (n:char[])=(snd n) in [|n.[g/n.Length];n.[g%n.Length]|] let p2c n (g:char[])=Array.item(let n=snd n in (Array.findIndex((=)g.[0]) n)*n.Length+(Array.findIndex((=)g.[1]) n))(fst n) let fN(g:string)=let e,d=let n=g|>Seq.sort|>List.ofSeq in (g|>Seq.mapi(fun i l->(List.findIndex((=)l)n)-i)|>Array.ofSeq,n|>Seq.mapi(fun i l->(Seq.findIndex((=)l)g)-i)|>Array.ofSeq)
(fun i->i+(e.[i%g.Length])),(fun i->i+(d.[i%g.Length]))
let ADFGVX n (g:string)=let pE,pD=fN g
(fun(s:string)->let a,b=s|>Seq.collect(c2p n)|>Array.ofSeq|>Array.splitAt(2*s.Length-(2*s.Length)%g.Length)
Array.append(Array.permute(pE) a)(Array.permute(fst(fN(g.[..b.Length-1]))) b)|>System.String),
(fun(s:string)->let a,b=s.ToCharArray()|>Array.splitAt(s.Length-(s.Length)%g.Length)
Array.append(Array.permute(pD) a)(Array.permute(snd(fN(g.[..b.Length-1]))) b)|>Array.chunkBySize 2|>Array.map(p2c n)|>System.String)
printPolybus polybus let encrypt,decrypt=ADFGVX polybus "nigel" //Using "nigel" as the key no hacker will guess that! let n=encrypt "ATTACKAT1200AM" in printfn $"\nATTACKAT1200AM encrypted is %s{n} which decrypted is %s{decrypt n}" </lang>
- Output:
A D F G V X
----------------
A| 6 U 9 B 2 H
D| C G O N Y R
F| T 8 D E V K
G| 1 Q X P L W
V| Z 0 I A J S
X| 7 4 3 M F 5
ATTACKAT1200AM encrypted is AFGFVDGVAAGVXFFAAGVADVDVVGXG which decrypted is ATTACKAT1200AM
Go
<lang go>package main
import (
"bytes" "fmt" "io/ioutil" "log" "math/rand" "sort" "strings" "time"
)
var adfgvx = "ADFGVX" var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
func distinct(bs []byte) []byte {
var u []byte
for _, b := range bs {
if !bytes.Contains(u, []byte{b}) {
u = append(u, b)
}
}
return u
}
func allAsciiAlphaNum(word []byte) bool {
for _, b := range word {
if !((b >= 48 && b <= 57) || (b >= 65 && b <= 90) || (b >= 97 && b <= 122)) {
return false
}
}
return true
}
func orderKey(key string) []int {
temp := make([][2]byte, len(key))
for i := 0; i < len(key); i++ {
temp[i] = [2]byte{key[i], byte(i)}
}
sort.Slice(temp, func(i, j int) bool { return temp[i][0] < temp[j][0] })
res := make([]int, len(key))
for i := 0; i < len(key); i++ {
res[i] = int(temp[i][1])
}
return res
}
func createPolybius() []string {
temp := []byte(alphabet)
rand.Shuffle(36, func(i, j int) {
temp[i], temp[j] = temp[j], temp[i]
})
alphabet = string(temp)
fmt.Println("6 x 6 Polybius square:\n")
fmt.Println(" | A D F G V X")
fmt.Println("---------------")
p := make([]string, 6)
for i := 0; i < 6; i++ {
fmt.Printf("%c | ", adfgvx[i])
p[i] = alphabet[6*i : 6*(i+1)]
for _, c := range p[i] {
fmt.Printf("%c ", c)
}
fmt.Println()
}
return p
}
func createKey(n int) string {
if n < 7 || n > 12 {
log.Fatal("Key should be within 7 and 12 letters long.")
}
bs, err := ioutil.ReadFile("unixdict.txt")
if err != nil {
log.Fatal("Error reading file")
}
words := bytes.Split(bs, []byte{'\n'})
var candidates [][]byte
for _, word := range words {
if len(word) == n && len(distinct(word)) == n && allAsciiAlphaNum(word) {
candidates = append(candidates, word)
}
}
k := string(bytes.ToUpper(candidates[rand.Intn(len(candidates))]))
fmt.Println("\nThe key is", k)
return k
}
func encrypt(polybius []string, key, plainText string) string {
temp := ""
outer:
for _, ch := range []byte(plainText) {
for r := 0; r <= 5; r++ {
for c := 0; c <= 5; c++ {
if polybius[r][c] == ch {
temp += fmt.Sprintf("%c%c", adfgvx[r], adfgvx[c])
continue outer
}
}
}
}
colLen := len(temp) / len(key)
// all columns need to be the same length
if len(temp)%len(key) > 0 {
colLen++
}
table := make([][]string, colLen)
for i := 0; i < colLen; i++ {
table[i] = make([]string, len(key))
}
for i := 0; i < len(temp); i++ {
table[i/len(key)][i%len(key)] = string(temp[i])
}
order := orderKey(key)
cols := make([][]string, len(key))
for i := 0; i < len(key); i++ {
cols[i] = make([]string, colLen)
for j := 0; j < colLen; j++ {
cols[i][j] = table[j][order[i]]
}
}
res := make([]string, len(cols))
for i := 0; i < len(cols); i++ {
res[i] = strings.Join(cols[i], "")
}
return strings.Join(res, " ")
}
func decrypt(polybius []string, key, cipherText string) string {
colStrs := strings.Split(cipherText, " ")
// ensure all columns are same length
maxColLen := 0
for _, s := range colStrs {
if len(s) > maxColLen {
maxColLen = len(s)
}
}
cols := make([][]string, len(colStrs))
for i, s := range colStrs {
var ls []string
for _, c := range s {
ls = append(ls, string(c))
}
if len(s) < maxColLen {
cols[i] = make([]string, maxColLen)
copy(cols[i], ls)
} else {
cols[i] = ls
}
}
table := make([][]string, maxColLen)
order := orderKey(key)
for i := 0; i < maxColLen; i++ {
table[i] = make([]string, len(key))
for j := 0; j < len(key); j++ {
table[i][order[j]] = cols[j][i]
}
}
temp := ""
for i := 0; i < len(table); i++ {
temp += strings.Join(table[i], "")
}
plainText := ""
for i := 0; i < len(temp); i += 2 {
r := strings.IndexByte(adfgvx, temp[i])
c := strings.IndexByte(adfgvx, temp[i+1])
plainText = plainText + string(polybius[r][c])
}
return plainText
}
func main() {
rand.Seed(time.Now().UnixNano())
plainText := "ATTACKAT1200AM"
polybius := createPolybius()
key := createKey(9)
fmt.Println("\nPlaintext :", plainText)
cipherText := encrypt(polybius, key, plainText)
fmt.Println("\nEncrypted :", cipherText)
plainText2 := decrypt(polybius, key, cipherText)
fmt.Println("\nDecrypted :", plainText2)
}</lang>
- Output:
Sample run:
6 x 6 Polybius square: | A D F G V X --------------- A | R W H N I 7 D | 1 J O 2 P 5 F | 3 A T 4 M 9 G | D U L K V 0 V | Z B E F 6 Q X | G Y S 8 C X The key is EUCHARIST Plaintext : ATTACKAT1200AM Encrypted : FDG FGG FVDV FFX FFF FFX DDD XAF DGG Decrypted : ATTACKAT1200AM
Julia
<lang julia>"""
The ADFGVX cipher. See also eg. https://www.nku.edu/~christensen/092hnr304%20ADFGVX.pdf
"""
using Random
""" The WWI German ADFGVX cipher. """ struct ADFGVX
polybius::Vector{Char}
pdim::Int
key::Vector{Char}
keylen::Int
alphabet::Vector{Char}
encode::Dict{Char, Vector{Char}}
decode::Dict{Vector{Char}, Char}
end
""" ADFGVX constructor, takes 2 strings, option for third string if polybius len != 36 """ function ADFGVX(s, k, alph = "ADFGVX")
poly = collect(uppercase(s))
pdim = isqrt(length(poly))
al = collect(uppercase(alph))
enco::Dict = Dict([(poly[(i - 1) * pdim + j] => [al[i], al[j]])
for i in 1:pdim, j in 1:pdim])
deco = Dict(last(p) => first(p) for p in enco)
@assert pdim^2 == length(poly) && pdim == length(al)
return ADFGVX(poly, pdim, collect(uppercase(k)), length(k), al, enco, deco)
end
""" Encrypt with the ADFGVX cipher. """ function encrypt(s::String, k::ADFGVX)
chars = reduce(vcat, [k.encode[c] for c in
filter(c -> c in k.polybius, collect(uppercase(s)))])
colvecs = [lett => chars[i:k.keylen:length(chars)] for (i, lett) in enumerate(k.key)]
sort!(colvecs, lt = (x, y) -> first(x) < first(y))
return String(mapreduce(p -> last(p), vcat, colvecs))
end
""" Decrypt with the ADFGVX cipher. Does not depend on spacing of encoded text """ function decrypt(s::String, k::ADFGVX)
chars = filter(c -> c in k.alphabet, collect(uppercase(s)))
sortedkey = sort(collect(k.key))
order = [findfirst(c -> c == ch, k.key) for ch in sortedkey]
originalorder = [findfirst(c -> c == ch, sortedkey) for ch in k.key]
a, b = divrem(length(chars), k.keylen)
strides = [a + (b >= i ? 1 : 0) for i in order] # shuffled column lengths
starts = accumulate(+, strides[begin:end-1], init=1) # shuffled starts of columns
pushfirst!(starts, 1) # starting index
ends = [starts[i] + strides[i] - 1 for i in 1:k.keylen] # shuffled ends of columns
cols = [chars[starts[i]:ends[i]] for i in originalorder] # get reordered columns
pairs, nrows = Char[], (length(chars) - 1) ÷ k.keylen + 1 # recover the rows
for i in 1:nrows, j in 1:k.keylen
(i - 1) * k.keylen + j > length(chars) && break
push!(pairs, cols[j][i])
end
return String([k.decode[[pairs[i], pairs[i + 1]]] for i in 1:2:length(pairs)-1])
end
const POLYBIUS = String(shuffle(collect("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"))) const KEY = read("unixdict.txt", String) |>
v -> split(v, r"\s+") |> v -> filter(w -> (n = length(w); n == 9 && n == length(unique(collect(w)))), v) |> shuffle |> first |> uppercase
const SECRETS, message = ADFGVX(POLYBIUS, KEY), "ATTACKAT1200AM" println("Polybius: $POLYBIUS, Key: $KEY") println("Message: $message") encoded = encrypt(message, SECRETS) decoded = decrypt(encoded, SECRETS) println("Encoded: $encoded") println("Decoded: $decoded")
</lang>
- Output:
Polybius: L4VZJIB8OXGFM1H3CTNKU9PE75WQ2DAYRS06, Key: SUNFLOWER Message: ATTACKAT1200AM Encoded: AFAXXVFAXFDXXFVFDFXVVAAGVXXX Decoded: ATTACKAT1200AM
Nim
It started as a translation, but actually we use a different method, better suited to Nim, to encrypt and decrypt. And there are many other differences. Output is similar though.
<lang Nim>import algorithm, random, sequtils, strutils, sugar, tables
const Adfgvx = "ADFGVX"
type PolybiusSquare = array[6, array[6, char]]
iterator items(p: PolybiusSquare): (int, int, char) =
## Yield Polybius square characters preceded by row and column numbers.
for r in 0..5:
for c in 0..5:
yield (r, c, p[r][c])
proc initPolybiusSquare(): PolybiusSquare =
## Initialize a 6x6 Polybius square.
var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
alphabet.shuffle()
for r in 0..5:
for c in 0..5:
result[r][c] = alphabet[6 * r + c]
proc createKey(n: Positive): string =
## Create a key using a word from "unixdict.txt".
doAssert n in 7..12, "Key should be within 7 and 12 letters long."
let candidates = collect(newSeq):
for word in "unixdict.txt".lines:
if word.len == n and
word.deduplicate().len == n and
word.allCharsInSet(Letters + Digits): word
result = candidates[rand(candidates.high)].toUpperAscii
func encrypt(plainText: string; polybius: PolybiusSquare; key: string): string =
## Encrypt "plaintext" using the given Polybius square and the given key.
# Replace characters by row+column letters.
var str: string
for ch in plainText:
for (r, c, val) in polybius:
if val == ch:
str.add Adfgvx[r] & Adfgvx[c]
# Build ordered table of columns and sort it by key value. var cols: OrderedTable[char, string] for i, ch in str: let tkey = key[i mod key.len] cols.mgetOrPut(tkey, "").add ch cols.sort(cmp)
# Build cipher text from sorted column table values.
for s in cols.values:
result.addSep(" ")
result.add s
func decrypt(cipherText: string; polybius: PolybiusSquare; key: string): string =
## Decrypt "cipherText" using the given Polybius square and the given key.
# Build list of columns.
let skey = sorted(key)
var cols = newSeq[string](key.len)
var idx = 0
for col in cipherText.split(' '):
cols[key.find(skey[idx])] = col
inc idx
# Build string of row+column values.
var str: string
for i in 0..key.high:
for col in cols:
if i < col.len: str.add col[i]
# Build plain text from row+column values. for i in countup(0, str.len - 2, 2): let r = Adfgvx.find(str[i]) let c = Adfgvx.find(str[i+1]) result.add polybius[r][c]
randomize()
var polybius = initPolybiusSquare() echo "6 x 6 Polybius square:\n" echo " | A D F G V X" echo "---------------" for i, row in polybius:
echo Adfgvx[i], " | ", row.join(" ")
let key = createKey(9) echo "\nThe key is ", key
const PlainText = "ATTACKAT1200AM" echo "\nPlaintext : ", PlainText
let cipherText = PlainText.encrypt(polybius, key) echo "\nEncrypted : ", cipherText
let plainText = cipherText.decrypt(polybius, key) echo "\nDecrypted : ", plainText</lang>
- Output:
6 x 6 Polybius square: | A D F G V X --------------- A | U 1 C N H F D | E M 4 R S G F | P I 8 9 6 5 G | X 2 Z B 7 K V | A 3 Y V O D X | 0 W Q T J L The key is PHAGOCYTE Plaintext : ATTACKAT1200AM Encrypted : XXX GXA ADD GVA AGD XAX VFGD AAA VGV Decrypted : ATTACKAT1200AM
Perl
<lang perl>#!/usr/bin/perl
use strict; # https://rosettacode.org/wiki/ADFGVX_cipher use warnings; use List::Util qw( shuffle );
my $plaintext = 'ATTACKAT1200AM'; my $keysize = 9;
my $polybius = <<END;
| A D F G V X
--+------------ A | x x x x x x D | x x x x x x F | x x x x x x G | x x x x x x V | x x x x x x X | x x x x x x END $polybius =~ s/x/$_/ for my @letters = shuffle "A" .. 'Z' , 0 .. 9; print "Polybius square =\n\n$polybius\n"; my %char2pair; @char2pair{ @letters } = glob '{A,D,F,G,V,X}' x 2; # map chars to pairs my %pair2char = reverse %char2pair; # map pairs to chars my ($keyword) = shuffle grep !/(.).*\1/,
do { local (@ARGV, $/) = 'unixdict.txt'; <> =~ /^.{$keysize}$/gm };
my ($n, @deorder) = 0; my @reorder = map /.(.+)/, sort map $_ . $n++, split //, $keyword; @deorder[@reorder] = 0 .. $#reorder; print " keyword = $keyword\n\nplaintext = $plaintext\n\n";
my $encoded = encode( $plaintext, \%char2pair, \@reorder ); print " encoded = $encoded\n\n";
my $decoded = decode( $encoded, \%pair2char, \@deorder ); print " decoded = $decoded\n";
sub encode
{
my ($plain, $c2p, $order) = @_;
my $len = @$order;
join ' ', (transpose( $plain =~ s/./$c2p->{$&}/gr =~ /.{1,$len}/g ))[@$order];
}
sub decode
{
my ($encoded, $p2c, $order) = @_;
(join , transpose((split ' ', $encoded)[@$order])) =~ s/../$p2c->{$&}/gr;
}
sub transpose { map join(, map {s/.// ? $& : } @_), 1 .. length $_[0] }</lang>
- Output:
Polybius square = | A D F G V X --+------------ A | 6 V Y E P N D | 1 C M 9 L H F | 8 T O U D F G | A R G 7 S 5 V | J 2 W Q I Z X | K B 3 0 X 4 keyword = benchmark plaintext = ATTACKAT1200AM encoded = GDG GDVF DGG AXD FAX DAD DFG FAX ADA decoded = ATTACKAT1200AM
Phix
We can make some nice use of the standard builtin routines here, with only a modest amount of whitespace cleanup.
with javascript_semantics constant ADFGVX = "ADFGVX", ALEPH = tagset('Z','A')&tagset('9','0') function create_polybius() string aleph = shuffle(ALEPH) -- string aleph = "U1CNHFEM4RSGPI8965X2ZB7KA3YVOD0WQTJL" -- Nim -- string aleph = "T71VB5HYG2JKIQM8REOPDUNCZ063FXAW9S4L" -- Wren -- string aleph = "NA1C3H8TB2OME5WRPD4F6G7I9J0KLQSUVXYZ" -- wp sequence tmp = split(join_by(aleph,1,6," "),'\n') printf(1,"6 x 6 Polybius square:\n") printf(1," | A D F G V X\n") printf(1,"---------------\n") for i=1 to length(tmp) do printf(1,"%s | %s\n",{ADFGVX[i],tmp[i]}) end for return aleph end function function lnua(string word, integer n) return length(word)==n and length(unique(word))==n and length(filter(word,"in",ALEPH))==n end function function create_key(integer n) assert(n>=7 and n<=12) sequence candidates = filter(upper(unix_dict()),lnua,n) string res = candidates[rand(length(candidates))] -- string res = "PHAGOCYTE" -- Nim -- string res = "SUNFLOWER" -- Wren -- string res = "PRIVACY" -- wp printf(1,"\nThe key is %s\n",{res}) return res end function function encrypt(string polybius, key, plaintext) integer l = length(key) sequence tags = custom_sort(key,tagset(l)), res = "" for i=1 to length(plaintext) do integer k = find(plaintext[i],polybius) if k then -- (simply ignore any non-alphanum) res &= ADFGVX[floor((k-1)/6)+1]& ADFGVX[remainder((k-1),6)+1] end if end for res = substitute(join(columnize(split_by(res,l),tags,' '))," "," ") return res end function function decrypt(string polybius, key, encrypted) integer l = length(key) sequence tags = custom_sort(key,tagset(l)), tmp = columnize(split(encrypted,' '),{},' ') tmp = trim(join(apply(true,extract,{tmp,{tags},true}),"")) string plaintext = "" for i=1 to length(tmp) by 2 do integer r = find(tmp[i],ADFGVX)-1, c = find(tmp[i+1],ADFGVX) plaintext &= polybius[r*6+c] end for return plaintext end function string polybius = create_polybius(), key = create_key(9), plaintext = "ATTACKAT1200AM", encrypted = encrypt(polybius,key,plaintext), decrypted = decrypt(polybius,key,encrypted) printf(1,"\nPlainText : %s\n\nEncrypted : %s\n\nDecrypted : %s\n", {plaintext, encrypted, decrypted})
Output matches Wren/Nim/wp when the appropriate lines are uncommented.
Python
This version and the Julia version do not reveal the key length by preserving spaces between columns, which completely removes column information, not just hiding which columns are first in the encoding. According to historical sources the original encrypted text was spaced in 5 character blocks regardless of message and key length, which means that decryption should not rely on spacing. <lang python>"""
The ADFGVX cipher implemented as a Python class See also eg. https://www.nku.edu/~christensen/092hnr304%20ADFGVX.pdf
"""
from random import shuffle, choice from itertools import product, accumulate from numpy import floor, sqrt
class ADFGVX:
""" The WWI German ADFGVX cipher. """
def __init__(self, spoly, k, alph='ADFGVX'):
self.polybius = list(spoly.upper())
self.pdim = int(floor(sqrt(len(self.polybius))))
self.key = list(k.upper())
self.keylen = len(self.key)
self.alphabet = list(alph)
pairs = [p[0] + p[1] for p in product(self.alphabet, self.alphabet)]
self.encode = dict(zip(self.polybius, pairs))
self.decode = dict((v, k) for (k, v) in self.encode.items())
def encrypt(self, msg):
""" Encrypt with the ADFGVX cipher. """
chars = list(.join([self.encode[c] for c in msg.upper() if c in self.polybius]))
colvecs = [(lett, chars[i:len(chars):self.keylen]) \
for (i, lett) in enumerate(self.key)]
colvecs.sort(key=lambda x: x[0])
return .join([.join(a[1]) for a in colvecs])
def decrypt(self, cod):
""" Decrypt with the ADFGVX cipher. Does not depend on spacing of encoded text """
chars = [c for c in cod if c in self.alphabet]
sortedkey = sorted(self.key)
order = [self.key.index(ch) for ch in sortedkey]
originalorder = [sortedkey.index(ch) for ch in self.key]
base, extra = divmod(len(chars), self.keylen)
strides = [base + (1 if extra > i else 0) for i in order] # shuffled column lengths
starts = list(accumulate(strides[:-1], lambda x, y: x + y)) # shuffled starts of columns
starts = [0] + starts # starting index
ends = [starts[i] + strides[i] for i in range(self.keylen)] # shuffled ends of columns
cols = [chars[starts[i]:ends[i]] for i in originalorder] # get reordered columns
pairs = [] # recover the rows
for i in range((len(chars) - 1) // self.keylen + 1):
for j in range(self.keylen):
if i * self.keylen + j < len(chars):
pairs.append(cols[j][i])
return .join([self.decode[pairs[i] + pairs[i + 1]] for i in range(0, len(pairs), 2)])
if __name__ == '__main__':
PCHARS = list('ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789')
shuffle(PCHARS)
POLYBIUS = .join(PCHARS)
with open('unixdict.txt') as fh:
WORDS = [w for w in (fh.read()).split() \
if len(w) == 9 and len(w) == len(set(list(w)))]
KEY = choice(WORDS)
SECRET, MESSAGE = ADFGVX(POLYBIUS, KEY), 'ATTACKAT1200AM'
print(f'Polybius: {POLYBIUS}, key: {KEY})
print('Message: ', MESSAGE)
ENCODED = SECRET.encrypt(MESSAGE)
DECODED = SECRET.decrypt(ENCODED)
print('Encoded: ', ENCODED)
print('Decoded: ', DECODED)
</lang>
- Output:
Polybius: A9GKMF1DQRSBVX8Z0WTEJLOPY5U4CN2H76I3, key: volcanism Message: ATTACKAT1200AM Encoded: GAFAAVAAAGGFVAAAGVAAAADAAVXV Decoded: ATTACKAT1200AM
Raku
Slightly different results from every other entry so far. See discussion page for reasons. It is impossible to tell from casual observation which column comes first in the Raku example. In every other (so far), the sub group with 4 characters is the first column. <lang perl6>srand 123456; # For repeatability
my @header = < A D F G V X >; my $polybius = (flat 'A'..'Z', 0..9).pick(*).join;
my $key-length = 9; my $key = uc 'unixdict.txt'.IO.words.grep( { (.chars == $key-length) && (+.comb.Set == +.comb) } ).roll;
my %cypher = (@header X~ @header) Z=> $polybius.comb;
my $message = 'Attack at 1200AM';
use Terminal::Boxer; say "Key: $key\n"; say "Polybius square:\n", ss-box :7col, :3cw, :indent("\t"), , |@header, |(@header Z $polybius.comb.batch: 6); say "Message to encode: $message"; say "\nEncoded: " ~ my $encoded = encode $message; say "\nDecoded: " ~ decode $encoded;
sub encode ($text is copy) {
$text = $text.uc.comb(/<[A..Z 0..9]>/).join;
my @order = $key.comb.pairs.sort( *.value )».key;
my @encode = %cypher.invert.hash{ $text.comb }.join.comb.batch($key-length).map: { [$_] };
((^$key-length).map: { @encode».[@order]».grep( *.defined )».[$_].grep( *.defined ).join }).Str;
}
sub decode ($text is copy) {
my @text = $text.split(' ')».comb;
my $chars = @text[0].chars;
$_ = flat |$_, ' ' if .chars < $chars for @text;
my @order = $key.comb.pairs.sort( *.value )».key.pairs.sort( *.value )».key;
%cypher{ ( grep { /\w/ }, flat [Z] @order.map( { |@text.batch($key-length)».[$_] } ) ).batch(2)».join }.join;
}</lang>
- Output:
Key: GHOSTLIKE Polybius square: ┌───┬───┬───┬───┬───┬───┬───┐ │ │ A │ D │ F │ G │ V │ X │ ├───┼───┼───┼───┼───┼───┼───┤ │ A │ H │ O │ S │ 5 │ 7 │ Q │ ├───┼───┼───┼───┼───┼───┼───┤ │ D │ 0 │ I │ 6 │ J │ C │ V │ ├───┼───┼───┼───┼───┼───┼───┤ │ F │ 4 │ 8 │ R │ X │ G │ A │ ├───┼───┼───┼───┼───┼───┼───┤ │ G │ Y │ F │ P │ B │ Z │ 3 │ ├───┼───┼───┼───┼───┼───┼───┤ │ V │ M │ W │ 9 │ D │ 1 │ N │ ├───┼───┼───┼───┼───┼───┼───┤ │ X │ 2 │ E │ U │ T │ L │ K │ └───┴───┴───┴───┴───┴───┴───┘ Message to encode: Attack at 1200AM Encoded: DVVA FVX XXA FGF XVX GXA XXD GFA XXD Decoded: ATTACKAT1200AM
Wren
<lang ecmascript>import "random" for Random import "/ioutil" for FileUtil import "/seq" for Lst import "/str" for Char, Str
var rand = Random.new() var adfgvx = "ADFGVX" var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toList
var createPolybius = Fn.new {
rand.shuffle(alphabet)
var p = Lst.chunks(alphabet, 6)
System.print("6 x 6 Polybius square:\n")
System.print(" | A D F G V X")
System.print("---------------")
for (i in 0...p.count) {
System.write("%(adfgvx[i]) | ")
System.print(p[i].join(" "))
}
return p
}
var createKey = Fn.new { |n|
if (n < 7 || n > 12) Fiber.abort("Key should be within 7 and 12 letters long.")
var candidates = FileUtil.readLines("unixdict.txt").where { |word|
return word.count == n && Lst.distinct(word.toList).count == n &&
word.all { |ch| Char.isAsciiAlphaNum(ch) }
}.toList
var k = Str.upper(candidates[rand.int(candidates.count)])
System.print("\nThe key is %(k)")
return k
}
// helper function to sort the key into alphabetical order // and return a list of the original indices of its letters. var orderKey = Fn.new { |key|
var temp = (0...key.count).map { |i| [key[i], i] }.toList
temp.sort { |x, y| x[0].bytes[0] < y[0].bytes[0] }
return temp.map { |e| e[1] }.toList
}
var encrypt = Fn.new { |polybius, key, plainText|
var temp = ""
for (ch in plainText) {
var outer = false
for (r in 0..5) {
for (c in 0..5) {
if (polybius[r][c] == ch) {
temp = temp + adfgvx[r] + adfgvx[c]
outer = true
break
}
}
if (outer) break
}
}
var colLen = (temp.count / key.count).floor
// all columns need to be the same length
if (temp.count % key.count > 0) colLen = colLen + 1
var table = Lst.chunks(temp.toList, key.count)
var lastLen = table[-1].count
if (lastLen < key.count) table[-1] = table[-1] + ([""] * (key.count - lastLen))
var order = orderKey.call(key)
var cols = List.filled(key.count, null)
for (i in 0...cols.count) {
cols[i] = List.filled(colLen, null)
for (j in 0...table.count) cols[i][j] = table[j][order[i]]
}
return cols.map { |col| col.join() }.join(" ")
}
var decrypt = Fn.new { |polybius, key, cipherText|
var colStrs = cipherText.split(" ")
// ensure all columns are same length
var maxColLen = colStrs.reduce(0) { |max, col| max = (col.count > max) ? col.count : max }
var cols = colStrs.map { |s|
return (s.count < maxColLen) ? s.toList + ([""] * (maxColLen - s.count)) : s.toList
}.toList
var table = List.filled(maxColLen, null)
var order = orderKey.call(key)
for (i in 0...maxColLen) {
table[i] = List.filled(key.count, "")
for (j in 0...key.count) table[i][order[j]] = cols[j][i]
}
var temp = table.map { |row| row.join("") }.join("")
var plainText = ""
var i = 0
while (i < temp.count) {
var r = adfgvx.indexOf(temp[i])
var c = adfgvx.indexOf(temp[i+1])
plainText = plainText + polybius[r][c]
i = i + 2
}
return plainText
}
var plainText = "ATTACKAT1200AM" var polybius = createPolybius.call() var key = createKey.call(9) System.print("\nPlaintext : %(plainText)") var cipherText = encrypt.call(polybius, key, plainText) System.print("\nEncrypted : %(cipherText)") var plainText2 = decrypt.call(polybius, key, cipherText) System.print("\nDecrypted : %(plainText2)")</lang>
- Output:
Sample run:
6 x 6 Polybius square: | A D F G V X --------------- A | T 7 1 V B 5 D | H Y G 2 J K F | I Q M 8 R E G | O P D U N C V | Z 0 6 3 F X X | A W 9 S 4 L The key is SUNFLOWER Plaintext : ATTACKAT1200AM Encrypted : AAA AXD AAV AXV AAD GFF XXDF ADG XAX Decrypted : ATTACKAT1200AM