Chaocipher

From Rosetta Code
Task
Chaocipher
You are encouraged to solve this task according to the task description, using any language you may know.

Description

The Chaocipher was invented by J.F.Byrne in 1918 and, although simple by modern cryptographic standards, does not appear to have been broken until the algorithm was finally disclosed by his family in 2010.

The algorithm is described in this paper by M.Rubin in 2010 and there is a C# implementation here.


Task

The task is to code the algorithm in your language and to test that it works with the plaintext 'WELLDONEISBETTERTHANWELLSAID' used in the paper itself.

Arc[edit]

(= lshift '((0 1) (2 14) (1 2) (14 26)))
(= rshift '((1 3) (4 15) (3 4) (15 26) (0 1)))
 
(= rot (fn (alpha shift)
(let shift (mod shift 26)
(string (cut alpha shift) (cut alpha 0 shift)))))
 
(= scramble-wheel (fn (alpha moves)
(= oput '())
(up i 0 (- (len moves) 1)
(push (cut alpha ((moves i) 0) ((moves i) 1)) oput))
(= oput (string (rev oput)))))
 
(= chaocipher (fn (left right msg (o crypted) (o dec?))
(unless crypted
(prn "Encoding " msg " with chaocipher")
(prn left " " right))
(when dec? (swap left right))
(= offset ((positions (msg 0) right) 0))
(= left (rot left offset))
(= right (rot right offset))
(push (cut left 0 1) crypted)
(when dec? (swap left right))
(prn (scramble-wheel left lshift)
" " (scramble-wheel right rshift))
(if (> (len msg) 1)
(chaocipher (scramble-wheel left lshift)
(scramble-wheel right rshift)
(cut msg 1) crypted dec?)
(string (rev crypted)))))
 
(chaocipher "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
"WELLDONEISBETTERTHANWELLSAID")
(chaocipher "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
"OAHQHCNYNXTSZJRRHJBYHQKSOUJY" nil 1)
 
Output:
 
arc> (chaocipher "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
"WELLDONEISBETTERTHANWELLSAID")
Encoding WELLDONEISBETTERTHANWELLSAID with chaocipher
HXUCZVAMDSLKPEFJRIGTWOBNYQ PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI
YFJBGMTKWNOQXCHIDVALZRSPUE JIBMESWKYZXUCOPRTLNHFAGVQD
"OAHQHCNYNXTSZJRRHJBYHQKSOUJY"
 

C[edit]

Translation of: Kotlin
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
 
#define TRUE 1
#define FALSE 0
 
typedef int bool;
typedef enum { ENCRYPT, DECRYPT } cmode;
 
const char *l_alphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
const char *r_alphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
 
void chao(const char *in, char *out, cmode mode, bool show_steps) {
int i, j, index;
char store;
size_t len = strlen(in);
char left[27], right[27], temp[27];
strcpy(left, l_alphabet);
strcpy(right, r_alphabet);
temp[26] = '\0';
 
for (i = 0; i < len; ++i ) {
if (show_steps) printf("%s  %s\n", left, right);
if (mode == ENCRYPT) {
index = strchr(right, in[i]) - right;
out[i] = left[index];
}
else {
index = strchr(left, in[i]) - left;
out[i] = right[index];
}
if (i == len - 1) break;
 
/* permute left */
 
for (j = index; j < 26; ++j) temp[j - index] = left[j];
for (j = 0; j < index; ++j) temp[26 - index + j] = left[j];
store = temp[1];
for (j = 2; j < 14; ++j) temp[j - 1] = temp[j];
temp[13] = store;
strcpy(left, temp);
 
/* permute right */
 
for (j = index; j < 26; ++j) temp[j - index] = right[j];
for (j = 0; j < index; ++j) temp[26 - index + j] = right[j];
store = temp[0];
for (j = 1; j < 26; ++j) temp[j - 1] = temp[j];
temp[25] = store;
store = temp[2];
for (j = 3; j < 14; ++j) temp[j - 1] = temp[j];
temp[13] = store;
strcpy(right, temp);
}
}
 
int main() {
const char *plain_text = "WELLDONEISBETTERTHANWELLSAID";
char *cipher_text = malloc(strlen(plain_text) + 1);
char *plain_text2 = malloc(strlen(plain_text) + 1);
printf("The original plaintext is : %s\n", plain_text);
printf("\nThe left and right alphabets after each permutation"
" during encryption are :\n\n");
chao(plain_text, cipher_text, ENCRYPT, TRUE);
printf("\nThe ciphertext is : %s\n", cipher_text);
chao(cipher_text, plain_text2, DECRYPT, FALSE);
printf("\nThe recovered plaintext is : %s\n", plain_text2);
free(cipher_text);
free(plain_text2);
return 0;
}
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are :

HXUCZVAMDSLKPEFJRIGTWOBNYQ  PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW  XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV  OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ  NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY  NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE  JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU  YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO  BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP  RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO  MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ  AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM  IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB  RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ  LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF  LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ  RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ  YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY  LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF  MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD  VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE  HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX  RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON  SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS  NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR  NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW  WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP  GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF  OBMESWKYZXUCPRTLNHFAGVQDJI

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

C#[edit]

Translation of: D
using System;
 
namespace Chaocipher {
enum Mode {
ENCRYPT,
DECRYPT,
}
 
class Program {
const string L_ALPHABET = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
const string R_ALPHABET = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
 
static string Exec(string text, Mode mode, bool showSteps = false) {
char[] left = L_ALPHABET.ToCharArray();
char[] right = R_ALPHABET.ToCharArray();
char[] eText = new char[text.Length];
char[] temp = new char[26];
 
for (int i = 0; i < text.Length; ++i) {
if (showSteps) Console.WriteLine("{0} {1}", string.Join("", left), string.Join("", right));
int index = 0;
if (mode == Mode.ENCRYPT) {
index = Array.IndexOf(right, text[i]);
eText[i] = left[index];
} else {
index = Array.IndexOf(left, text[i]);
eText[i] = right[index];
}
if (i == text.Length - 1) break;
 
// permute left
 
for (int j = index; j < 26; ++j) temp[j - index] = left[j];
for (int j = 0; j < index; ++j) temp[26 - index + j] = left[j];
var store = temp[1];
for (int j = 2; j < 14; ++j) temp[j - 1] = temp[j];
temp[13] = store;
temp.CopyTo(left, 0);
 
// permute right
 
for (int j = index; j < 26; ++j) temp[j - index] = right[j];
for (int j = 0; j < index; ++j) temp[26 - index + j] = right[j];
store = temp[0];
for (int j = 1; j < 26; ++j) temp[j - 1] = temp[j];
temp[25] = store;
store = temp[2];
for (int j = 3; j < 14; ++j) temp[j - 1] = temp[j];
temp[13] = store;
temp.CopyTo(right, 0);
}
 
return new string(eText);
}
 
static void Main(string[] args) {
var plainText = "WELLDONEISBETTERTHANWELLSAID";
Console.WriteLine("The original plaintext is : {0}", plainText);
Console.WriteLine("\nThe left and right alphabets after each permutation during encryption are :\n");
var cipherText = Exec(plainText, Mode.ENCRYPT, true);
Console.WriteLine("\nThe ciphertext is : {0}", cipherText);
var plainText2 = Exec(cipherText, Mode.DECRYPT);
Console.WriteLine("\nThe recovered plaintext is : {0}", plainText2);
}
}
}
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are :

HXUCZVAMDSLKPEFJRIGTWOBNYQ PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

D[edit]

Translation of: Kotlin
import std.stdio;
import std.string;
 
immutable L_ALPHABET = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
immutable R_ALPHABET = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
 
enum Mode {
ENCRYPT,
DECRYPT,
}
 
string exec(string text, Mode mode, bool showSteps = false) {
char[] left = L_ALPHABET.dup;
char[] right = R_ALPHABET.dup;
char[] eText;
eText.length = text.length;
char[26] temp;
 
foreach (i; 0..text.length) {
if (showSteps) writeln(left, ' ', right);
int index;
if (mode == Mode.ENCRYPT) {
index = right.indexOf(text[i]);
eText[i] = left[index];
} else {
index = left.indexOf(text[i]);
eText[i] = right[index];
}
if (i == text.length - 1) break;
 
// permute left
 
foreach (j; index..26) temp[j - index] = left[j];
foreach (j; 0..index) temp[26 - index + j] = left[j];
auto store = temp[1];
foreach (j; 2..14) temp[j - 1] = temp[j];
temp[13] = store;
left = temp.dup;
 
// permute right
 
foreach (j; index..26) temp[j - index] = right[j];
foreach (j; 0..index) temp[26 - index + j] = right[j];
store = temp[0];
foreach (j; 1..26) temp[j - 1] = temp[j];
temp[25] = store;
store = temp[2];
foreach (j; 3..14) temp[j - 1] = temp[j];
temp[13] = store;
right = temp.dup;
}
 
return eText.idup;
}
 
void main() {
auto plainText = "WELLDONEISBETTERTHANWELLSAID";
writeln("The original plaintext is : ", plainText);
writeln("\nThe left and right alphabets after each permutation during encryption are :\n");
auto cipherText = exec(plainText, Mode.ENCRYPT, true);
writeln("\nThe ciphertext is : ", cipherText);
auto plainText2 = exec(cipherText, Mode.DECRYPT);
writeln("\nThe recovered plaintext is : ", plainText2);
}
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are :

HXUCZVAMDSLKPEFJRIGTWOBNYQ PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

F#[edit]

The Functions[edit]

 
// Implement Chaocipher. Nigel Galloway: July 13th., 2019
let pL n=function g when g=n->0 |g when g=(n+1)%26->13 |g->let x=(25+g-n)%26 in if x<13 then x else x+1
let pR n=function g when g=n->25 |g when g=(n+3)%26->13 |g when g=(n+1)%26->0 |g when g=(n+2)%26->1 |g->let x=(24+g-n)%26 in if x<13 then x else x+1
let encrypt lW rW txt=Array.scan(fun (lW,rW) t->let n=Array.findIndex(fun n->n=t) rW in ((Array.permute(pL n) lW,(Array.permute(pR n) rW))))(lW,rW) txt
|>Array.skip 1|>Array.map(fun(n,_)->n.[0])|>System.String
let decrypt lW rW txt=Array.scan(fun (_,lW,rW) t->let n=Array.findIndex(fun n->n=t) lW in ((Array.item n rW,Array.permute(pL n) lW,(Array.permute(pR n) rW))))('0',lW,rW) txt
|>Array.skip 1|>Array.map(fun(n,_,_)->n)|>System.String
 

The Task[edit]

 
printfn "%s" (encrypt ("HXUCZVAMDSLKPEFJRIGTWOBNYQ".ToCharArray()) ("PTLNBQDEOYSFAVZKGJRIHWXUMC".ToCharArray()) ("WELLDONEISBETTERTHANWELLSAID".ToCharArray()))
printfn "%s" (decrypt ("HXUCZVAMDSLKPEFJRIGTWOBNYQ".ToCharArray()) ("PTLNBQDEOYSFAVZKGJRIHWXUMC".ToCharArray()) ("OAHQHCNYNXTSZJRRHJBYHQKSOUJY".ToCharArray()))
 
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

Factor[edit]

USING: arrays combinators fry io kernel locals math namespaces
prettyprint sequences sequences.extras strings ;
IN: rosetta-code.chaocipher
 
CONSTANT: zenith 0
CONSTANT: nadir 13
 
SYMBOLS: l-alphabet r-alphabet last-index ;
 
: init-alphabets ( -- )
"HXUCZVAMDSLKPEFJRIGTWOBNYQ" l-alphabet
"PTLNBQDEOYSFAVZKGJRIHWXUMC" r-alphabet [ set ] [email protected] ;
 
: zero-alphabet ( seq -- seq' )
last-index get rotate ;
 
: 3append ( a b c d -- abcd )
append append append ;
 
:: permute-l-alphabet ( -- )
l-alphabet get zero-alphabet dup
zenith 1 + swap nth :> extracted-char
{
[ 1 head ]
[ nadir 1 + head 2 tail ]
[ drop extracted-char 1string ]
[ nadir 1 + tail ]
} cleave
3append l-alphabet set ;
 
:: permute-r-alphabet ( -- )
r-alphabet get zero-alphabet
1 rotate dup
zenith 2 + swap nth :> extracted-char
{
[ 2 head ]
[ nadir 1 + head 3 tail ]
[ drop extracted-char 1string ]
[ nadir 1 + tail ]
} cleave
3append r-alphabet set ;
 
: encipher-char ( char alpha1 alpha2 -- char' )
'[ _ get index dup last-index set _ get nth ] call ;
 
: encipher ( str quot -- str' )
[ permute-l-alphabet permute-r-alphabet ] compose map
init-alphabets ; inline
 
: encrypt ( str -- str' )
[ r-alphabet l-alphabet encipher-char ] encipher ;
 
: decrypt ( str -- str' )
[ l-alphabet r-alphabet encipher-char ] encipher ;
 
: main ( -- )
init-alphabets
"WELLDONEISBETTERTHANWELLSAID" encrypt dup decrypt
[ print ] [email protected] ;
 
MAIN: main
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

Go[edit]

Translation of: Kotlin
package main
 
import(
"fmt"
"strings"
"unicode/utf8"
)
 
type Mode int
 
const(
Encrypt Mode = iota
Decrypt
)
 
const(
lAlphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
rAlphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
)
 
func Chao(text string, mode Mode, showSteps bool) string {
len := len(text)
if utf8.RuneCountInString(text) != len {
fmt.Println("Text contains non-ASCII characters")
return ""
}
left := lAlphabet
right := rAlphabet
eText := make([]byte, len)
temp := make([]byte, 26)
 
for i := 0; i < len; i++ {
if showSteps {
fmt.Println(left, " ", right)
}
var index int
if mode == Encrypt {
index = strings.IndexByte(right, text[i])
eText[i] = left[index]
} else {
index = strings.IndexByte(left, text[i])
eText[i] = right[index]
}
if i == len - 1 {
break
}
 
// permute left
for j := index; j < 26; j++ {
temp[j - index] = left[j]
}
for j := 0; j < index; j++ {
temp[26 - index + j] = left[j]
}
store := temp[1]
for j := 2; j < 14; j++ {
temp[j - 1] = temp[j]
}
temp[13] = store
left = string(temp[:])
 
// permute right
 
for j := index; j < 26; j++ {
temp[j - index] = right[j]
}
for j := 0; j < index; j++ {
temp[26 - index + j] = right[j]
}
store = temp[0]
for j := 1; j < 26; j++ {
temp[j - 1] = temp[j]
}
temp[25] = store
store = temp[2]
for j := 3; j < 14; j++ {
temp[j - 1] = temp[j]
}
temp[13] = store
right = string(temp[:])
}
 
return string(eText[:])
}
 
func main() {
plainText := "WELLDONEISBETTERTHANWELLSAID"
fmt.Println("The original plaintext is :", plainText)
fmt.Print("\nThe left and right alphabets after each permutation ")
fmt.Println("during encryption are :\n")
cipherText := Chao(plainText, Encrypt, true)
fmt.Println("\nThe ciphertext is :", cipherText)
plainText2 := Chao(cipherText, Decrypt, false)
fmt.Println("\nThe recovered plaintext is :", plainText2)
}
Output:
Same as Kotlin entry.

Haskell[edit]

import Data.List (elemIndex)
 
chao :: Eq a => [a] -> [a] -> Bool -> [a] -> [a]
chao _ _ _ [] = []
chao l r plain (x:xs) = maybe [] go (elemIndex x src)
where
(src, dst)
| plain = (l, r)
| otherwise = (r, l)
go n =
dst !! n :
chao
(shifted 1 14 (rotated n l))
((shifted 2 14 . shifted 0 26) (rotated n r))
plain
xs
 
rotated :: Int -> [a] -> [a]
rotated z s = take (length s) (drop z (cycle s))
 
shifted :: Int -> Int -> [a] -> [a]
shifted src dst s =
let (a, b) = splitAt dst s
(x, y) = splitAt src a
in concat [x, rotated 1 y, b]
 
encode = False
 
decode = True
 
main :: IO ()
main = do
let chaoWheels =
chao "HXUCZVAMDSLKPEFJRIGTWOBNYQ" "PTLNBQDEOYSFAVZKGJRIHWXUMC"
plainText = "WELLDONEISBETTERTHANWELLSAID"
cipherText = chaoWheels encode plainText
print plainText
print cipherText
print $ chaoWheels decode cipherText
Output:
"WELLDONEISBETTERTHANWELLSAID"
"OAHQHCNYNXTSZJRRHJBYHQKSOUJY"
"WELLDONEISBETTERTHANWELLSAID"

JavaScript[edit]

Translation of: C

Script source

const L_ALPHABET = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
const R_ALPHABET = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
 
const ENCRYPT = 0;
const DECRYPT = 1;
 
function setCharAt(str, index, chr) {
if (index > str.length - 1) return str;
return str.substr(0, index) + chr + str.substr(index + 1);
}
 
function chao(text, mode, show_steps) {
var left = L_ALPHABET;
var right = R_ALPHABET;
var out = text;
var temp = "01234567890123456789012345";
var i = 0;
var index, j, store;
 
if (show_steps) {
console.log("The left and right alphabets after each permutation during encryption are :");
}
while (i < text.length) {
if (show_steps) {
console.log(left + " " + right);
}
if (mode == ENCRYPT) {
index = right.indexOf(text[i]);
out = setCharAt(out, i, left[index]);
} else {
index = left.indexOf(text[i]);
out = setCharAt(out, i, right[index]);
}
if (i == text.length - 1) {
break;
}
 
//permute left
j = index;
while (j < 26) {
temp = setCharAt(temp, j - index, left[j])
j += 1;
}
j = 0;
while (j < index) {
temp = setCharAt(temp, 26 - index + j, left[j]);
j += 1;
}
store = temp[1];
j = 2;
while (j < 14) {
temp = setCharAt(temp, j - 1, temp[j]);
j += 1;
}
temp = setCharAt(temp, 13, store);
left = temp;
 
//permute right
j = index;
while (j < 26) {
temp = setCharAt(temp, j - index, right[j]);
j += 1;
}
j = 0;
while (j < index) {
temp = setCharAt(temp, 26 - index + j, right[j]);
j += 1;
}
store = temp[0];
j = 1;
while (j < 26) {
temp = setCharAt(temp, j - 1, temp[j]);
j += 1;
}
temp = setCharAt(temp, 25, store);
store = temp[2];
j = 3;
while (j < 14) {
temp = setCharAt(temp, j - 1, temp[j]);
j += 1;
}
temp = setCharAt(temp, 13, store);
right = temp;
 
i += 1;
}
 
return out;
}
 
function main() {
var out = document.getElementById("content");
const plain_text = "WELLDONEISBETTERTHANWELLSAID";
 
out.innerHTML = "<p>The original plaintext is : " + plain_text + "</p>";
var cipher_text = chao(plain_text, ENCRYPT, true);
out.innerHTML += "<p>The ciphertext is : " + cipher_text + "</p>";
var decipher_text = chao(cipher_text, DECRYPT, false);
out.innerHTML += "<p>The recovered plaintext is : " + decipher_text + "</p>";
}

Solution page

<!DOCTYPE html>
<html>
<head>
<title>Chaocipher</title>
<script src="chaocipher.js"></script>
</head>
<body onload="main()">
<div id="content"></div>
</body>
</html>
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID
The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY
The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

Julia[edit]

Modified from the Kotlin and Perl 6 entries.

const leftalphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
const rightalphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
 
function chacocoding(text, encoding, verbose=false)
left, right = Vector{Char}(leftalphabet), Vector{Char}(rightalphabet)
len, coded = length(text), similar(Vector{Char}(text))
for i in 1:len
verbose && println(String(left), " ", String(right))
n = indexin(text[i], encoding ? right : left)[1]
coded[i] = encoding ? left[n] : right[n]
if i < len
left .= circshift(left, -n + 1)
left[2:14] .= circshift(left[2:14], -1)
right .= circshift(right, -n)
right[3:14] .= circshift(right[3:14], -1)
end
end
String(coded)
end
 
function testchacocipher(txt)
println("The original plaintext is: $txt")
println("\nThe left and right alphabets for each character during encryption are:")
encoded = chacocoding(txt, true, true)
println("\nThe encoded ciphertext is: $encoded")
decoded = chacocoding(encoded, false)
println("\nDecoded, the recovered plaintext is: $decoded")
end
 
testchacocipher("WELLDONEISBETTERTHANWELLSAID")
 
Output:
The original plaintext is: WELLDONEISBETTERTHANWELLSAID

The left and right alphabets for each character during encryption are:
HXUCZVAMDSLKPEFJRIGTWOBNYQ   PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW   XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV   OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ   NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY   NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE   JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU   YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO   BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP   RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO   MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ   AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM   IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB   RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ   LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF   LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ   RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ   YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY   LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF   MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD   VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE   HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX   RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON   SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS   NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR   NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW   WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP   GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF   OBMESWKYZXUCPRTLNHFAGVQDJI

The encoded ciphertext is: OAHQHCNYNXTSZJRRHJBYHQKSOUJY

Decoded, the recovered plaintext is: WELLDONEISBETTERTHANWELLSAID

Kotlin[edit]

This is based on the C# implementation referred to in the task description, except that the encrypt and decrypt operations are combined into a single method.

// Version 1.2.40
 
enum class Mode { ENCRYPT, DECRYPT }
 
object Chao {
private val lAlphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
private val rAlphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
 
fun exec(text: String, mode: Mode, showSteps: Boolean = false): String {
var left = lAlphabet
var right = rAlphabet
val eText = CharArray(text.length)
val temp = CharArray(26)
 
for (i in 0 until text.length) {
if (showSteps) println("$left $right")
var index: Int
if (mode == Mode.ENCRYPT) {
index = right.indexOf(text[i])
eText[i] = left[index]
}
else {
index = left.indexOf(text[i])
eText[i] = right[index]
}
if (i == text.length - 1) break
 
// permute left
 
for (j in index..25) temp[j - index] = left[j]
for (j in 0 until index) temp[26 - index + j] = left[j]
var store = temp[1]
for (j in 2..13) temp[j - 1] = temp[j]
temp[13] = store
left = String(temp)
 
// permute right
 
for (j in index..25) temp[j - index] = right[j]
for (j in 0 until index) temp[26 - index + j] = right[j]
store = temp[0]
for (j in 1..25) temp[j - 1] = temp[j]
temp[25] = store
store = temp[2]
for (j in 3..13) temp[j - 1] = temp[j]
temp[13] = store
right = String(temp)
}
 
return String(eText)
}
}
 
fun main(args: Array<String>) {
val plainText = "WELLDONEISBETTERTHANWELLSAID"
println("The original plaintext is : $plainText")
println("\nThe left and right alphabets after each permutation" +
" during encryption are :\n")
val cipherText = Chao.exec(plainText, Mode.ENCRYPT, true)
println("\nThe ciphertext is : $cipherText")
val plainText2 = Chao.exec(cipherText, Mode.DECRYPT)
println("\nThe recovered plaintext is : $plainText2")
}
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are :

HXUCZVAMDSLKPEFJRIGTWOBNYQ  PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW  XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV  OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ  NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY  NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE  JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU  YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO  BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP  RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO  MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ  AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM  IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB  RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ  LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF  LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ  RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ  YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY  LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF  MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD  VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE  HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX  RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON  SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS  NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR  NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW  WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP  GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF  OBMESWKYZXUCPRTLNHFAGVQDJI

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

Objeck[edit]

Translation of: Kotlin
class Chaocipher {
L_ALPHABET : static : Char[];
R_ALPHABET : static : Char[];
 
function : Main(args : String[]) ~ Nil {
L_ALPHABET := "HXUCZVAMDSLKPEFJRIGTWOBNYQ"->ToCharArray();
R_ALPHABET := "PTLNBQDEOYSFAVZKGJRIHWXUMC"->ToCharArray();
plainText := "WELLDONEISBETTERTHANWELLSAID"->ToCharArray();
 
System.IO.Console->Print("The original plaintext is: ")->PrintLine(plainText);
"\nThe left and right alphabets after each permutation during encryption are:\n"->PrintLine();
cipherText := Chao(plainText, Mode->ENCRYPT, true);
System.IO.Console->Print("\nThe ciphertext is: ")->PrintLine(cipherText);
plainText2 := Chao(cipherText, Mode->DECRYPT, false);
System.IO.Console->Print("The recovered plaintext is: ")->PrintLine(plainText2);
}
 
function : Chao(in : Char[], mode : Mode, show_steps : Bool) ~ Char[] {
i : Int; j : Int; index : Int;
store : Char;
len := in->Size();
left := Char->New[26]; right := Char->New[26]; temp := Char->New[26];
eText := Char->New[len];
 
Runtime->Copy(left, 0, L_ALPHABET, 0, L_ALPHABET->Size());
Runtime->Copy(right, 0, R_ALPHABET, 0, R_ALPHABET->Size());
 
for(i := 0; i < len; i += 1;) {
if (show_steps) {
System.IO.Console->Print(left)->Print(' ')->PrintLine(right);
};
if (mode = Mode->ENCRYPT) {
index := IndexOf(right, in[i]);
eText[i] := left[index];
}
else {
index := IndexOf(left, in[i]);
eText[i] := right[index];
};
 
if (i = len - 1) {
break;
};
 
# left
for(j := index; j < 26; j += 1;) { temp[j - index] := left[j]; };
for(j :=0; j < index; j += 1;) { temp[26 - index + j] := left[j]; };
store := temp[1];
for(j := 2; j < 14; j += 1;) { temp[j - 1] := temp[j]; };
temp[13] := store;
Runtime->Copy(left, 0, temp, 0, temp->Size());
 
# right
for(j := index; j < 26; j += 1;) { temp[j - index] := right[j]; };
for(j :=0; j < index; j += 1;) { temp[26 - index + j] := right[j]; };
store := temp[0];
for(j :=1; j < 26; j += 1;) { temp[j - 1] := temp[j]; };
temp[25] := store;
store := temp[2];
for(j := 3; j < 14; j += 1;) { temp[j - 1] := temp[j]; };
temp[13] := store;
Runtime->Copy(right, 0, temp, 0, temp->Size());
};
 
return eText;
}
 
function : IndexOf(str : Char[], c : Char) ~ Int {
for(i := 0; i < str->Size(); i += 1;) {
if(c = str[i]) {
return i;
};
};
 
return -1;
}
 
enum Mode { ENCRYPT, DECRYPT }
}
Output:
The original plaintext is: WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are:

HXUCZVAMDSLKPEFJRIGTWOBNYQ PTLNBQDEOYSFAVZKGJRIHWXUMC
ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI

The ciphertext is: OAHQHCNYNXTSZJRRHJBYHQKSOUJY
The recovered plaintext is: WELLDONEISBETTERTHANWELLSAID

Perl[edit]

Translation of: Perl 6

Since rotate is not a built-in in Perl, using a custom one, not general-purpose but sufficient for this task.

sub init {
@left = split '', 'HXUCZVAMDSLKPEFJRIGTWOBNYQ';
@right = split '', 'PTLNBQDEOYSFAVZKGJRIHWXUMC';
}
 
sub encode {
my($letter) = @_;
my $index = index join('', @right), $letter;
my $enc = $left[$index];
left_permute($index);
right_permute($index);
$enc
}
 
sub decode {
my($letter) = @_;
my $index = index join('', @left), $letter;
my $dec = $right[$index];
left_permute($index);
right_permute($index);
$dec
}
 
sub right_permute {
my($index) = @_;
rotate(\@right, $index + 1);
rotate(\@right, 1, 2, 13);
}
 
sub left_permute {
my($index) = @_;
rotate(\@left, $index);
rotate(\@left, 1, 1, 13);
}
 
sub rotate {
our @list; local *list = shift;
my($n,$s,$e) = @_;
@list = $s ? @list[0..$s-1, $s+$n..$e+$n-1, $s..$s+$n-1, $e+1..$#list]
: @list[$n..$#list, 0..$n-1]
}
 
init; $e_msg .= encode($_) for split '', 'WELLDONEISBETTERTHANWELLSAID';
init; $d_msg .= decode($_) for split '', $e_msg;
 
print "$e_msg\n";
print "$d_msg\n";
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

Perl 6[edit]

Works with: Rakudo version 2018.03
my @left;
my @right;
 
sub reset {
@left = <HXUCZVAMDSLKPEFJRIGTWOBNYQ>.comb;
@right = <PTLNBQDEOYSFAVZKGJRIHWXUMC>.comb;
}
 
sub encode ($letter) {
my $index = @right.first: $letter.uc, :k;
my $enc = @left[$index];
$index.&permute;
$enc
}
 
sub decode ($letter) {
my $index = @left.first: $letter.uc, :k;
my $dec = @right[$index];
$index.&permute;
$dec
}
 
sub permute ($index) {
@left.=rotate: $index;
@left[1..13].=rotate;
@right.=rotate: $index + 1;
@right[2..13].=rotate;
}
 
reset;
say 'WELLDONEISBETTERTHANWELLSAID'.comb».&encode.join;
reset;
say 'OAHQHCNYNXTSZJRRHJBYHQKSOUJY'.comb».&decode.join;
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

Phix[edit]

Originally translated from C, but ended up more of a direct implementation of the algorithm in the pdf.

-- demo\rosetta\Chao_cipher.exw
constant l_alphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ",
r_alphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
 
enum ENCRYPT, DECRYPT
 
function chao_cipher(string in, integer mode, bool show_steps)
integer len = length(in)
string out = repeat(' ',len)
string left = l_alphabet,
right = r_alphabet
for i=1 to len do
if show_steps then printf(1,"%s  %s\n", {left, right}) end if
integer index = find(in[i],iff(mode==ENCRYPT?right:left))
out[i] = iff(mode==ENCRYPT?left:right)[index]
 
if i==len then exit end if
 
/* permute left */
left = left[index..26]&left[1..index-1]
left[2..14] = left[3..14]&left[2]
 
/* permute right */
right = right[index+1..26]&right[1..index]
right[3..14] = right[4..14]&right[3]
end for
return out
end function
 
string plain_text = "WELLDONEISBETTERTHANWELLSAID"
printf(1,"The original plaintext is : %s\n", {plain_text})
 
--printf(1,"\nThe left and right alphabets after each permutation"&
-- " during encryption are :\n\n")
--string cipher_text = chao_cipher(plain_text, ENCRYPT, true)
string cipher_text = chao_cipher(plain_text, ENCRYPT, false)
printf(1,"\nThe ciphertext is : %s\n", {cipher_text})
 
string plain_text2 = chao_cipher(cipher_text, DECRYPT, false)
printf(1,"\nThe recovered plaintext is : %s\n", {plain_text2})
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID

Python[edit]

 
# Python3 implementation of Chaocipher
# left wheel = ciphertext wheel
# right wheel = plaintext wheel
 
def main():
# letters only! makealpha(key) helps generate lalpha/ralpha.
lalpha = "HXUCZVAMDSLKPEFJRIGTWOBNYQ"
ralpha = "PTLNBQDEOYSFAVZKGJRIHWXUMC"
msg = "WELLDONEISBETTERTHANWELLSAID"
 
print("L:", lalpha)
print("R:", ralpha)
print("I:", msg)
print("O:", do_chao(msg, lalpha, ralpha, 1, 0), "\n")
 
do_chao(msg, lalpha, ralpha, 1, 1)
 
def do_chao(msg, lalpha, ralpha, en=1, show=0):
msg = correct_case(msg)
out = ""
if show:
print("="*54)
print(10*" " + "left:" + 21*" " + "right: ")
print("="*54)
print(lalpha, ralpha, "\n")
for L in msg:
if en:
lalpha, ralpha = rotate_wheels(lalpha, ralpha, L)
out += lalpha[0]
else:
ralpha, lalpha = rotate_wheels(ralpha, lalpha, L)
out += ralpha[0]
lalpha, ralpha = scramble_wheels(lalpha, ralpha)
if show:
print(lalpha, ralpha)
return out
 
def makealpha(key=""):
alpha = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
z = set()
key = [x.upper() for x in (key + alpha[::-1])
if not (x.upper() in z or z.add(x.upper()))]
return "".join(key)
 
def correct_case(string):
return "".join([s.upper() for s in string if s.isalpha()])
 
def permu(alp, num):
alp = alp[:num], alp[num:]
return "".join(alp[::-1])
 
def rotate_wheels(lalph, ralph, key):
newin = ralph.index(key)
return permu(lalph, newin), permu(ralph, newin)
 
def scramble_wheels(lalph, ralph):
# LEFT = cipher wheel
# Cycle second[1] through nadir[14] forward
lalph = list(lalph)
lalph = "".join([*lalph[0],
*lalph[2:14],
lalph[1],
*lalph[14:]])
 
# RIGHT = plain wheel
# Send the zenith[0] character to the end[25],
# cycle third[2] through nadir[14] characters forward
ralph = list(ralph)
ralph = "".join([*ralph[1:3],
*ralph[4:15],
ralph[3],
*ralph[15:],
ralph[0]])
return lalph, ralph
 
main()
L: HXUCZVAMDSLKPEFJRIGTWOBNYQ
R: PTLNBQDEOYSFAVZKGJRIHWXUMC
I: WELLDONEISBETTERTHANWELLSAID
O: OAHQHCNYNXTSZJRRHJBYHQKSOUJY 

======================================================
          left:                     right: 
======================================================
HXUCZVAMDSLKPEFJRIGTWOBNYQ PTLNBQDEOYSFAVZKGJRIHWXUMC 

ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI
YFJBGMTKWNOQXCHIDVALZRSPUE JIBMESWKYZXUCOPRTLNHFAGVQD

OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

Ruby[edit]

txt    = "WELLDONEISBETTERTHANWELLSAID"
@left = "HXUCZVAMDSLKPEFJRIGTWOBNYQ".chars
@right = "PTLNBQDEOYSFAVZKGJRIHWXUMC".chars
 
def encrypt(char)
coded_char = @left[@right.index(char)]
 
@left.rotate!(@left.index(coded_char))
part = @left.slice!(1,13).rotate
@left.insert(1, *part)
 
@right.rotate!(@right.index(char)+1)
part = @right.slice!(2,12).rotate
@right.insert(2, *part)
 
@left[0]
end
 
puts txt.each_char.map{|c| encrypt(c) }.join
 
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY

Rust[edit]

const LEFT_ALPHABET_CT: &str = "HXUCZVAMDSLKPEFJRIGTWOBNYQ";
const RIGHT_ALPHABET_PT: &str = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
const ZENITH: usize = 0;
const NADIR: usize = 12;
const SEQUENCE: &str = "WELLDONEISBETTERTHANWELLSAID";
 
fn cipher(letter: &char, left: &String, right: &String) -> (usize, char) {
let pos = right.find(*letter).unwrap();
let cipher = left.chars().nth(pos).unwrap();
(pos, cipher)
}
 
fn main() {
let mut left = LEFT_ALPHABET_CT.to_string();
let mut right = RIGHT_ALPHABET_PT.to_string();
 
let ciphertext = SEQUENCE.chars()
.map(|letter| {
let (pos, cipher_char) = cipher(&letter, &left, &right);
left = format!("{}{}", &left[pos..], &left[..pos]);
left = format!("{}{}{}{}", &left[ZENITH..1], &left[2..NADIR+2], &left[1..2], &left[NADIR+2..]);
if pos != right.len() - 1 {
right = format!("{}{}", &right[pos + 1..], &right[..pos + 1]);
}
right = format!("{}{}{}{}", &right[ZENITH..2], &right[3..NADIR+2], &right[2..3], &right[NADIR+2..]);
cipher_char
})
.collect::<String>();
 
println!("Plaintext: {}", SEQUENCE);
println!("Ciphertext: {}", ciphertext);
}
Output:
Plaintext: WELLDONEISBETTERTHANWELLSAID
Ciphertext: OAHQHCNYNXTSZJRRHJBYHQKSOUJY

Tailspin[edit]

 
templates [email protected]{left:,right:,decode:}
templates permute
def ctshift: [ [email protected]($..-1)..., [email protected](1..$-1)...];
def p1: $ mod 26 + 1;
def ptshift: [ [email protected]($p1..-1)..., [email protected](1..$p1-1)...];
..|@chaocipher: { ct: [ $ctshift(1), $ctshift(3..14)..., $ctshift(2), $ctshift(15..-1)...],
pt: [ $ptshift(1..2)..., $ptshift(4..14)..., $ptshift(3), $ptshift(15..-1)...] };
end permute
 
@: {ct:[ $left... ], pt: [ $right... ], result:[]};
$... -> #
'[email protected];' !
 
<?($decode <0>)>
def plain: $;
def index: [email protected] -> [i](<$plain> $i!) -> $(1);
..|@.result: [email protected]($index);
$index -> permute -> !VOID
<>
def cipher: $;
def index: [email protected] -> [i](<$cipher> $i!) -> $(1);
..|@.result: [email protected]($index);
$index -> permute -> !VOID
end chaocipher
 
'WELLDONEISBETTERTHANWELLSAID' -> [email protected]{left:'HXUCZVAMDSLKPEFJRIGTWOBNYQ', right:'PTLNBQDEOYSFAVZKGJRIHWXUMC',decode:0} -> '$;
' -> !OUT::write
 
'OAHQHCNYNXTSZJRRHJBYHQKSOUJY' -> [email protected]{left:'HXUCZVAMDSLKPEFJRIGTWOBNYQ', right:'PTLNBQDEOYSFAVZKGJRIHWXUMC',decode:1} -> '$;
' -> !OUT::write
 
Output:
OAHQHCNYNXTSZJRRHJBYHQKSOUJY
WELLDONEISBETTERTHANWELLSAID

zkl[edit]

Translation of: perl6
class Chao{
var [const private] lAlphabet = "HXUCZVAMDSLKPEFJRIGTWOBNYQ",
rAlphabet = "PTLNBQDEOYSFAVZKGJRIHWXUMC";
fcn encode(text){ code(text,encodeL); }
fcn decode(text){ code(text,decodeL); }
// reset alphabets each [en|de]code and maintain re-entrancy
fcn code(text,f){ text.apply(f,Data(Void,lAlphabet),Data(Void,rAlphabet)) }
fcn [private] encodeL(letter,left,right){ // encode a letter
index:=right.index(letter);
enc  :=left[index].toChar();
permute(left,right,index);
println(left.text," ",right.text," ",index);
enc
}
fcn [private] decodeL(letter,left,right){ // decode a letter
index:=left.index(letter);
dec  :=right[index].toChar();
permute(left,right,index);
dec
}
fcn [private] permute(left,right,index){
left.append(left.pop(0,index)); // rotate index times
left.insert(13,left.pop(1)); // rotate [1..13] once
 
right.append(right.pop(0,index+1)); # rotate index+1 times, idx==25==noop
right.insert(13,right.pop(2)); // rotate [2..13] once
}
}
plainText:="WELLDONEISBETTERTHANWELLSAID";
println("The original plaintext is : ",plainText);
println("\nThe left and right alphabets after each permutation"
" during encryption are:");
cipherText:=Chao.encode(plainText);
println("\nThe ciphertext is : ",cipherText);
 
plainText2:=Chao.decode(cipherText);
println("\nThe recovered plaintext is : ",plainText2);
Output:
The original plaintext is : WELLDONEISBETTERTHANWELLSAID

The left and right alphabets after each permutation during encryption are:
ONYQHXUCZVAMDBSLKPEFJRIGTW XUCPTLNBQDEOYMSFAVZKGJRIHW  21
ADBSLKPEFJRIGMTWONYQHXUCZV OYSFAVZKGJRIHMWXUCPTLNBQDE  10
HUCZVADBSLKPEXFJRIGMTWONYQ NBDEOYSFAVZKGQJRIHMWXUCPTL  20
QUCZVADBSLKPEHXFJRIGMTWONY NBEOYSFAVZKGQDJRIHMWXUCPTL  25
HFJRIGMTWONYQXUCZVADBSLKPE JRHMWXUCPTLNBIEOYSFAVZKGQD  13
CVADBSLKPEHFJZRIGMTWONYQXU YSAVZKGQDJRHMFWXUCPTLNBIEO  15
NQXUCVADBSLKPYEHFJZRIGMTWO BIOYSAVZKGQDJERHMFWXUCPTLN  21
YHFJZRIGMTWONEQXUCVADBSLKP RHFWXUCPTLNBIMOYSAVZKGQDJE  13
NQXUCVADBSLKPEYHFJZRIGMTWO MOSAVZKGQDJERYHFWXUCPTLNBI  12
XCVADBSLKPEYHUFJZRIGMTWONQ AVKGQDJERYHFWZXUCPTLNBIMOS  2
TONQXCVADBSLKWPEYHUFJZRIGM IMSAVKGQDJERYOHFWZXUCPTLNB  21
SKWPEYHUFJZRILGMTONQXCVADB RYHFWZXUCPTLNOBIMSAVKGQDJE  10
ZILGMTONQXCVARDBSKWPEYHUFJ LNBIMSAVKGQDJOERYHFWZXUCPT  10
JILGMTONQXCVAZRDBSKWPEYHUF LNIMSAVKGQDJOBERYHFWZXUCPT  25
RBSKWPEYHUFJIDLGMTONQXCVAZ RYFWZXUCPTLNIHMSAVKGQDJOBE  14
RSKWPEYHUFJIDBLGMTONQXCVAZ YFZXUCPTLNIHMWSAVKGQDJOBER  0
HFJIDBLGMTONQUXCVAZRSKWPEY LNHMWSAVKGQDJIOBERYFZXUCPT  7
JDBLGMTONQUXCIVAZRSKWPEYHF MWAVKGQDJIOBESRYFZXUCPTLNH  2
BGMTONQUXCIVALZRSKWPEYHFJD VKQDJIOBESRYFGZXUCPTLNHMWA  2
YFJDBGMTONQUXHCIVALZRSKWPE HMAVKQDJIOBESWRYFGZXUCPTLN  21
HIVALZRSKWPEYCFJDBGMTONQUX RYGZXUCPTLNHMFAVKQDJIOBESW  13
QXHIVALZRSKWPUEYCFJDBGMTON SWYGZXUCPTLNHRMFAVKQDJIOBE  23
KPUEYCFJDBGMTWONQXHIVALZRS NHMFAVKQDJIOBRESWYGZXUCPTL  10
SPUEYCFJDBGMTKWONQXHIVALZR NHFAVKQDJIOBRMESWYGZXUCPTL  25
OQXHIVALZRSPUNEYCFJDBGMTKW WYZXUCPTLNHFAGVKQDJIOBRMES  15
UEYCFJDBGMTKWNOQXHIVALZRSP GVQDJIOBRMESWKYZXUCPTLNHFA  12
JBGMTKWNOQXHIDVALZRSPUEYCF OBMESWKYZXUCPRTLNHFAGVQDJI  5
YFJBGMTKWNOQXCHIDVALZRSPUE JIBMESWKYZXUCOPRTLNHFAGVQD  23

The ciphertext is : OAHQHCNYNXTSZJRRHJBYHQKSOUJY

The recovered plaintext is : WELLDONEISBETTERTHANWELLSAID