Straddling checkerboard: Difference between revisions
Alextretyak (talk | contribs) (Added 11l) |
m (→{{header|REXX}}: added whitespace.) |
||
Line 2,337:
:* support the usage of a blank in the 1<sup>st</sup> character (the top line of the table).
<lang rexx>/*REXX program uses the straddling checkerboard cipher to encrypt/decrypt a message. */
parse arg msg
if msg='' then msg= 'One night-it was the twentieth of March, 1888-I was returning'
say 'plain text=' msg
call genCipher 'et aon ris', 'bcdfghjklm', 'pq/uvwxyz.' /*build the cipher (board)*/
enc= encrypt(msg); say ' encrypted=' enc
dec= decrypt(enc); say ' decrypted=' dec
exit
/*──────────────────────────────────────────────────────────────────────────────────────*/
genCipher: @.=; arg @..,two,three; z= -1; @.z= @..
_= pos(' ', @.. ) - 1; @._= two
_= pos(' ', @.., _+2) - 1; @._= three
do j=0 for 9; @..= @.. || @.j
if @.j\=='' then @.r= @.r || j
_= pos('/', @.j)
if _\==0 then @.dig= j || (_-1)
end /*j*/
@..= space(@.., 0);
/*──────────────────────────────────────────────────────────────────────────────────────*/
encrypt: procedure expose @.; arg !,,$ /*$: output (encrypted text) so far.*/
do j=1 for length(!) /*process each of the plain─text chars.*/
x= substr(!, j, 1)
if datatype(x, 'W') then do; $= $ || @.dig || x; iterate; end /*numeral?
if pos(x, @..)==0 then iterate /*Not one of the allowable chars? Skip*/
do k=-1 for 10; y= pos(x, @.k)
if y==0 then iterate /*Not in this row? Then keep looking.*/
z= k;
$= $ || z || (y-1);
end /*k*/
end /*j*/; return $
/*──────────────────────────────────────────────────────────────────────────────────────*/
decrypt: procedure expose @.; parse arg !,,$
do j=1 to length(!); rw= -1
if substr(!,j,2)==@.dig then do; j= j+2; $= $ ||
if pos(x, @.r)\==0 then do; j= j+1; rw=x; x=substr(!, j, 1);
$= $ || substr(@.rw, x+1, 1)
end /*j*/; return $</lang>
{{out|output|text= when using the default input:}}
<pre>
|
Revision as of 05:07, 6 July 2021
You are encouraged to solve this task according to the task description, using any language you may know.
- Task
Implement functions to encrypt and decrypt a message using the straddling checkerboard method. The checkerboard should take a 28 character alphabet (A-Z plus a full stop and an escape character) and two different numbers representing the blanks in the first row. The output will be a series of decimal digits.
Numbers should be encrypted by inserting the escape character before each digit, then including the digit unencrypted. This should be reversed for decryption.
11l
<lang 11l>V t = [[String(‘79’), ‘0’, ‘1’, ‘2’, ‘3’, ‘4’, ‘5’, ‘6’, ‘7’, ‘8’, ‘9’],
[String(‘’), ‘H’, ‘O’, ‘L’, ‘’, ‘M’, ‘E’, ‘S’, ‘’, ‘R’, ‘T’], [String(‘3’), ‘A’, ‘B’, ‘C’, ‘D’, ‘F’, ‘G’, ‘I’, ‘J’, ‘K’, ‘N’], [String(‘7’), ‘P’, ‘Q’, ‘U’, ‘V’, ‘W’, ‘X’, ‘Y’, ‘Z’, ‘.’, ‘/’]]
F straddle(s)
R multiloop_filtered(Array(s.uppercase()), :t, (c, l) -> c C l, (c, l) -> l[0]‘’:t[0][l.index(c)]).join(‘’)
F unstraddle(s)
[String] r V si = 0 F next() R @s[@si++] L I si == s.len L.break V c = s[si++] I c C (:t[2][0], :t[3][0]) V i = [:t[2][0], :t[3][0]].index(c) V n = :t[2 + i][:t[0].index(next())] r [+]= I n == ‘/’ {next()} E n E r [+]= :t[1][:t[0].index(c)] R r
V O = ‘One night-it was on the twentieth of March, 1888-I was returning’ print(‘Encoded: ’straddle(O)) print(‘Decoded: ’unstraddle(straddle(O)).join(‘’))</lang>
- Output:
Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
ALGOL 68
Note: This specimen retains the original C++ coding style.
<lang algol68>#!/usr/local/bin/a68g --script #
PRIO MIN=5, MAX=5; OP MIN = (INT a, b)INT: (a<b|a|b),
MAX = (INT a, b)INT: (a>b|a|b);
MODE STRADDLINGCHECKERBOARD=STRUCT(
[0:9]CHAR first, second, third, [ABS ".": ABS "Z"]STRING table, INT row u, row v, CHAR esc, skip
);
STRUCT(
PROC (REF STRADDLINGCHECKERBOARD #self#, STRING #alphabet#, INT #u#, INT #v#)VOID init, PROC (REF STRADDLINGCHECKERBOARD #self#, STRING #plain#)STRING encode, PROC (REF STRADDLINGCHECKERBOARD #self#, STRING #plain#)STRING decode
) sc class = (
- PROC init = # (REF STRADDLINGCHECKERBOARD self, STRING in alphabet, INT u, v)VOID:
( STRING alphabet = in alphabet[@0];
esc OF self := alphabet[UPB alphabet]; # use the last CHAR as the escape # skip OF self := alphabet[UPB alphabet-1];
row u OF self := u MIN v; row v OF self := u MAX v;
OP DIGIT = (INT i)CHAR: REPR(ABS "0" + i );
INT j := LWB alphabet;
# (first OF self)[u] := (first OF self)[v] := skip; #
FOR i FROM LWB first OF self TO UPB first OF self DO IF i NE u AND i NE v THEN (first OF self)[i] := alphabet[j]; (table OF self)[ABS alphabet[j]] := DIGIT i; j+:=1 FI;
(second OF self)[i] := alphabet[i+8]; (table OF self)[ABS alphabet[i+8]] := DIGIT (row u OF self) + DIGIT i;
(third OF self)[i] := alphabet[i+18]; (table OF self)[ABS alphabet[i+18]] := DIGIT (row v OF self) + DIGIT i OD ),
- PROC encode = # (REF STRADDLINGCHECKERBOARD self, STRING plain)STRING:
( STRING esc = (table OF self)[ABS (esc OF self)]; INT l2u = ABS "A" - ABS "a";
STRING out := ""; FOR i FROM LWB plain TO UPB plain DO CHAR c := plain[i]; IF "a" <= c AND c <= "z" THEN c := REPR ( ABS c + l2u) FI;
IF "A" <= c AND c <= "Z" THEN out +:= (table OF self)[ABS c] ELIF "0" <= c AND c <= "9" THEN out +:= esc + c FI OD; out # EXIT # ),
- PROC decode = # (REF STRADDLINGCHECKERBOARD self, STRING cipher)STRING:
( CHAR null = REPR 0; STRING out; INT state := 0; FOR i FROM LWB cipher TO UPB cipher DO INT n := ABS cipher[i] - ABS "0";
CHAR next := CASE state IN #1:# (second OF self)[n], #2:# (third OF self)[n], #3:# cipher[i] OUT IF n = row u OF self THEN state := 1; null ELIF n = row v OF self THEN state := 2; null ELSE (first OF self)[n] FI ESAC;
IF next = "/" THEN state := 3 ELIF next NE null THEN state := 0; out +:= next FI OD; out # EXIT # )
);
main: (
STRADDLINGCHECKERBOARD sc; (init OF sc class)(sc, "HOLMESRTABCDFGIJKNPQUVWXYZ./", 3, 7);
STRING original := "One night-it was on the twentieth of March, 1888-I was returning"[@0]; STRING en := (encode OF sc class)(sc, original); STRING de := (decode OF sc class)(sc, en);
printf(($ggl$, "Original: ", original, "Encoded: ", en, "Decoded: ", de ))
)</lang> Output:
Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
AutoHotkey
<lang AutoHotkey>board := " ( ET AON RIS BCDFGHJKLM PQ/UVWXYZ. )" Text = One night-it was on the twentieth of March, 1888-I was returning StringUpper, Text, Text Text := RegExReplace(text, "[^A-Z0-9]") Num2 := InStr(board, A_Space) -1 Num3 := InStr(board, A_Space, true, Num1+1) -1 Loop Parse, Text { char := A_LoopField Loop Parse, board, `n { If (Pos := InStr(A_LoopField, char)) out .= Num%A_Index% . Pos-1 else if (Pos := InStr(A_LoopField, "/")) && InStr("0123456789", char) out .= Num%A_Index% . Pos-1 . char } } MsgBox % out
i := 0 While (LoopField := SubStr(out, ++i, 1)) <> "" { If (LoopField = num2) or (LoopField = num3) col := SubStr(out, ++i, 1) else col := 0 Loop Parse, board, `n { If !col && A_Index = 1 dec .= SubStr(A_LoopField, LoopField+1, 1) Else If (Num%A_Index% = LoopField) && col dec .= SubStr(A_LoopField, col+1, 1) If SubStr(dec, 0) = "/" dec := SubStr(dec, 1, StrLen(dec)-1) . SubStr(out, ++i, 1) } } MsgBox % dec</lang>
C
<lang c>#include <stdio.h>
- include <stdlib.h>
- include <string.h>
- include <stdbool.h>
- include <ctype.h>
- include <glib.h>
- define ROWS 4
- define COLS 10
- define NPRX "/"
/* wikipedia table const char *table[ROWS][COLS] = {
{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" }, { "E", "T", NULL, "A", "O", "N", NULL, "R", "I", "S }, { "B", "C", "D", "F", "G", "H", "J", "K", "L", "M" }, { "P", "Q", NPRX, "U", "V", "W", "X", "Y", "Z", "." }
};
- /
/* example of extending the table, COLS must be 11 const char *table[ROWS][COLS] = {
{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", ":" }, { "H", "O", "L", NULL, "M", "E", "S", NULL, "R", "T", "," }, { "A", "B", "C", "D", "F", "G", "I", "J", "K", "N", "-" }, { "P", "Q", "U", "V", "W", "X", "Y", "Z", ".", NPRX, "?" }
};
- /
// task table const char *table[ROWS][COLS] = {
{ "0", "1", "2", "3", "4", "5", "6", "7", "8", "9" }, { "H", "O", "L", NULL, "M", "E", "S", NULL, "R", "T" }, { "A", "B", "C", "D", "F", "G", "I", "J", "K", "N" }, { "P", "Q", "U", "V", "W", "X", "Y", "Z", ".", NPRX }
};
GHashTable *create_table_from_array(const char *table[ROWS][COLS], bool is_encoding)
{
char buf[16];
GHashTable *r = g_hash_table_new_full(g_str_hash, g_str_equal, free, free); size_t i, j, k, m;
for(i = 0, m = 0; i < COLS; i++) { if (table[1][i] == NULL) m++; }
const size_t SELNUM = m; size_t selectors[SELNUM]; size_t numprefix_row, numprefix_col; bool has_numprefix = false;
// selectors keep the indexes of the symbols to select 2nd and 3rd real row; // nulls must be placed into the 2nd row of the table for(i = 0, k = 0; i < COLS && k < SELNUM; i++) { if ( table[1][i] == NULL ) { selectors[k] = i; k++; } }
// numprefix is the prefix to insert symbols from the 1st row of table (numbers) for(j = 1; j < ROWS; j++) { for(i = 0; i < COLS; i++) { if (table[j][i] == NULL) continue; if ( strcmp(table[j][i], NPRX) == 0 ) { numprefix_col = i; numprefix_row = j; has_numprefix = true;
break;
} } }
// create the map for each symbol for(i = has_numprefix ? 0 : 1; i < ROWS; i++) { for(j = 0; j < COLS; j++) { if (table[i][j] == NULL) continue; if (strlen(table[i][j]) > 1) {
fprintf(stderr, "symbols must be 1 byte long\n"); continue; // we continue just ignoring the issue
} if (has_numprefix && i == (ROWS-1) && j == numprefix_col && i == numprefix_row) continue; if (has_numprefix && i == 0) {
snprintf(buf, sizeof(buf), "%s%s%s", table[0][selectors[SELNUM-1]], table[0][numprefix_col], table[0][j]);
} else if (i == 1) {
snprintf(buf, sizeof(buf), "%s", table[0][j]);
} else {
snprintf(buf, sizeof(buf), "%s%s", table[0][selectors[i-2]], table[0][j]);
} if (is_encoding) g_hash_table_insert(r, strdup(table[i][j]), strdup(buf)); else g_hash_table_insert(r, strdup(buf), strdup(table[i][j])); } } if (is_encoding) g_hash_table_insert(r, strdup("mode"), strdup("encode")); else g_hash_table_insert(r, strdup("mode"), strdup("decode"));
return r;
}
char *decode(GHashTable *et, const char *enctext) {
char *r = NULL;
if (et == NULL || enctext == NULL || strlen(enctext) == 0 || g_hash_table_lookup(et, "mode") == NULL || strcmp(g_hash_table_lookup(et, "mode"), "decode") != 0) return NULL;
GString *res = g_string_new(NULL); GString *en = g_string_new(NULL);
for( ; *enctext != '\0'; enctext++ ) { if (en->len < 3) { g_string_append_c(en, *enctext); r = g_hash_table_lookup(et, en->str); if (r == NULL) continue; g_string_append(res, r); g_string_truncate(en, 0); } else { fprintf(stderr, "decoding error\n"); break; } } r = res->str; g_string_free(res, FALSE); g_string_free(en, TRUE); return r;
}
char *encode(GHashTable *et, const char *plaintext, int (*trasf)(int), bool compress_spaces) {
GString *s; char *r = NULL; char buf[2] = { 0 };
if (plaintext == NULL || et == NULL || g_hash_table_lookup(et, "mode") == NULL || strcmp(g_hash_table_lookup(et, "mode"), "encode") != 0) return NULL;
s = g_string_new(NULL);
for(buf[0] = trasf ? trasf(*plaintext) : *plaintext; buf[0] != '\0'; buf[0] = trasf ? trasf(*++plaintext) : *++plaintext) { if ( (r = g_hash_table_lookup(et, buf)) != NULL ) { g_string_append(s, r); } else if (isspace(buf[0])) { if (!compress_spaces) g_string_append(s, buf); } else { fprintf(stderr, "char '%s' is not encodable%s\n",
isprint(buf[0]) ? buf : "?", !compress_spaces ? ", replacing with a space" : "");
if (!compress_spaces) g_string_append_c(s, ' '); } }
r = s->str; g_string_free(s, FALSE); return r;
}
int main()
{
GHashTable *enctab = create_table_from_array(table, true); // is encoding? true GHashTable *dectab = create_table_from_array(table, false); // is encoding? false (decoding)
const char *text = "One night-it was on the twentieth of March, 1888-I was returning";
char *encoded = encode(enctab, text, toupper, true); printf("%s\n", encoded);
char *decoded = decode(dectab, encoded); printf("%s\n", decoded);
free(decoded); free(encoded); g_hash_table_destroy(enctab); g_hash_table_destroy(dectab);
return 0;
}</lang>
Shorter version
<lang C>#include <stdio.h>
- include <stdlib.h>
const char * board = "ET AON RIS"
"BCDFGHJKLM" "PQ/UVWXYZ.";
char encode[128] = {0}; char decode[128] = {0}; int row[2] = {0};
void read_table(const char *s) {
int i, code; for (i = 0; i < 30; i++) { if (s[i] == '\0') { fprintf(stderr, "Table too short\n"); exit(1); }
if (s[i] == ' ') { row[ row[0] ? 1 : 0 ] = i; continue; }
code = ((i < 10) ? 0 : i < 20 ? row[0] : row[1]) * 10 + (i % 10); encode[0 + s[i]] = code; /* guess what 0 + s[i] does, sigh */ decode[code] = s[i]; }
}
void encipher(const char *in, char *out, int strip) {
- define PUTCODE(c) { if (c > 9) {*(out++) = c / 10 + '0'; c %= 10;} *(out++) = c + '0'; }
int c, code; while ((c = *(in++)) != '\0') { if (c >= '0' && c <= '9') { code = encode['.']; c -= '0'; PUTCODE(code); PUTCODE(c); continue; }
c &= ~0x20;
if (c >= 'A' && c <= 'Z') code = encode[c]; else if (strip && !c ) continue; else code = encode['/'];
PUTCODE(code); } *(out++) = '\0';
}
void decipher(const char *in, char *out, int strip) {
int c; while ((c = *(in++)) != '\0') { c -= '0'; if (c == row[0] || c == row[1]) c = c * 10 + *(in++) - '0';
c = decode[c];
if (c == '.') c = *(in++); if (c == '/' && !strip) c = ' '; *(out++) = c; } *(out++) = '\0';
}
int main() {
const char *msg = "In the winter 1965/we were hungry/just barely alive"; char enc[100] = {0}, dec[100] = {0}; read_table(board);
printf("message: %s\n", msg); encipher(msg, enc, 0); printf("encoded: %s\n", enc); decipher(enc, dec, 0); printf("decoded: %s\n", dec);
printf("\nNo spaces:\n"); encipher(msg, enc, 1); printf("encoded: %s\n", enc); decipher(enc, dec, 1); printf("decoded: %s\n", dec); return 0;
}</lang>Output:<lang>message: In the winter 1965/we were hungry/just barely alive encoded: 85621250626585107626916996966956265062650706225635247676226639162203702867623288640 decoded: IN THE WINTER 1965 WE WERE HUNGRY JUST BARELY ALIVE
No spaces: encoded: 851250658510769169969669562650650702563524767622663912037028673288640 decoded: INTHEWINTER1965/WEWEREHUNGRY/JUSTBARELYALIVE</lang>
C#
Translation of Java via D <lang csharp>using System; using System.Collections.Generic; using System.Linq; using System.Text.RegularExpressions;
namespace StraddlingCheckerboard {
class Program { public readonly static IReadOnlyDictionary<char, string> val2Key; public readonly static IReadOnlyDictionary<string, char> key2Val;
static Program() { val2Key = new Dictionary<char, string> { {'A',"30"}, {'B',"31"}, {'C',"32"}, {'D',"33"}, {'E',"5"}, {'F',"34"}, {'G',"35"}, {'H',"0"}, {'I',"36"}, {'J',"37"}, {'K',"38"}, {'L',"2"}, {'M',"4"}, {'.',"78"}, {'N',"39"}, {'/',"79"}, {'O',"1"}, {'0',"790"}, {'P',"70"}, {'1',"791"}, {'Q',"71"}, {'2',"792"}, {'R',"8"}, {'3',"793"}, {'S',"6"}, {'4',"794"}, {'T',"9"}, {'5',"795"}, {'U',"72"}, {'6',"796"},{'V',"73"}, {'7',"797"}, {'W',"74"}, {'8',"798"}, {'X',"75"}, {'9',"799"}, {'Y',"76"}, {'Z',"77"}};
key2Val = val2Key.ToDictionary(kv => kv.Value, kv => kv.Key); }
public static string Encode(string s) { return string.Concat(s.ToUpper().ToCharArray() .Where(c => val2Key.ContainsKey(c)).Select(c => val2Key[c])); }
public static string Decode(string s) { return string.Concat(Regex.Matches(s, "79.|7.|3.|.").Cast<Match>() .Where(m => key2Val.ContainsKey(m.Value)).Select(m => key2Val[m.Value])); }
static void Main(string[] args) { var enc = Encode("One night-it was on the twentieth of March, 1888-I was returning"); Console.WriteLine(enc); Console.WriteLine(Decode(enc));
Console.ReadLine(); } }
}</lang>
139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
C++
<lang cpp>#include <iostream>
- include <string>
- include <map>
- include <algorithm> // for min, max
using namespace std;
class StraddlingCheckerboard {
map<char, string> table; char first[10], second[10], third[10]; int rowU, rowV;
public:
StraddlingCheckerboard(const string &alphabet, int u, int v) { rowU = min(u, v); rowV = max(u, v);
for(int i = 0, j = 0; i < 10; ++i) { if(i != u && i != v) { first[i] = alphabet[j]; table[alphabet[j]] = '0' + i; ++j; }
second[i] = alphabet[i+8]; table[alphabet[i+8]] = '0' + rowU; table[alphabet[i+8]] += '0' + i;
third[i] = alphabet[i+18]; table[alphabet[i+18]] = '0' + rowV; table[alphabet[i+18]] += '0' + i; } }
string encode(const string &plain) { string out; for(int i = 0; i < plain.size(); ++i) { char c = plain[i]; if(c >= 'a' && c <= 'z') c += 'A' - 'a';
if(c >= 'A' && c <= 'Z') out += table[c]; else if(c >= '0' && c <= '9') { out += table['/']; out += c; } } return out; }
string decode(const string &cipher) { string out; int state = 0; for(int i = 0; i < cipher.size(); ++i) { int n = cipher[i] - '0'; char next = 0;
if(state == 1) next = second[n]; else if(state == 2) next = third[n]; else if(state == 3) next = cipher[i]; else if(n == rowU) state = 1; else if(n == rowV) state = 2; else next = first[n];
if(next == '/') state = 3; else if(next != 0) { state = 0; out += next; } } return out; }
};</lang>
Test program: <lang cpp>int main() {
StraddlingCheckerboard sc("HOLMESRTABCDFGIJKNPQUVWXYZ./", 3, 7); string original = "One night-it was on the twentieth of March, 1888-I was returning"; string en = sc.encode(original); string de = sc.decode(en);
cout << "Original: " << original << endl; cout << "Encoded: " << en << endl; cout << "Decoded: " << de << endl;
return 0;
}</lang>
Output:
Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
D
Partially based on the PicoLisp version: <lang d>import std.stdio, std.algorithm, std.string, std.array;
immutable T = ["79|0|1|2|3|4|5|6|7|8|9", "|H|O|L||M|E|S||R|T",
"3|A|B|C|D|F|G|I|J|K|N", "7|P|Q|U|V|W|X|Y|Z|.|/"] .map!(r => r.split("|")).array;
enum straddle = (in string s) pure /*nothrow @safe*/ =>
toUpper(s) .split("") .cartesianProduct(T) .filter!(cL => cL[1].canFind(cL[0])) .map!(cL => cL[1][0] ~ T[0][cL[1].countUntil(cL[0])]) .join;
string unStraddle(string s) pure nothrow @safe {
string result; for (; !s.empty; s.popFront) { immutable i = [T[2][0], T[3][0]].countUntil([s[0]]); if (i >= 0) { s.popFront; immutable n = T[2 + i][T[0].countUntil([s[0]])]; if (n == "/") { s.popFront; result ~= s[0]; } else result ~= n; } else result ~= T[1][T[0].countUntil([s[0]])]; } return result;
}
void main() {
immutable O = "One night-it was on the twentieth of March, 1888-I was returning"; writeln("Encoded: ", O.straddle); writeln("Decoded: ", O.straddle.unStraddle);
}</lang>
- Output:
Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Alternative Version
Same output: <lang d>import std.stdio, std.algorithm, std.ascii;
struct StraddlingCheckerboard {
private: string[char] table; char[10] first, second, third; const int rowU, rowV;
public: this(in string alphabet, in int u, in int v) pure nothrow { rowU = min(u, v); rowV = max(u, v);
int j = 0; foreach (immutable i; 0 .. 10) { if (i != u && i != v) { first[i] = alphabet[j]; table[alphabet[j]] = digits[i .. i + 1]; j++; }
second[i] = alphabet[i + 8]; table[alphabet[i + 8]] = [digits[rowU], digits[i]];
third[i] = alphabet[i + 18]; table[alphabet[i + 18]] = [digits[rowV], digits[i]]; } }
string encode(in string plain) const pure nothrow { string r; foreach (immutable char c; plain) { if (c.isLower) r ~= table[c.toUpper]; else if (c.isUpper) r ~= table[c]; else if (c.isDigit) r ~= table['/'] ~ c; } return r; }
string decode(in string cipher) const pure nothrow { string r; int state = 0;
foreach (immutable char c; cipher) { immutable int n = c - '0'; char next = '\0';
if (state == 1) next = second[n]; else if (state == 2) next = third[n]; else if (state == 3) next = c; else if (n == rowU) state = 1; else if (n == rowV) state = 2; else next = first[n];
if (next == '/') state = 3; else if (next != 0) { state = 0; r ~= next; } } return r; }
}
void main() {
immutable orig = "One night-it was on the twentieth of March, 1888-I was returning"; writeln("Original: ", orig); const sc = StraddlingCheckerboard("HOLMESRTABCDFGIJKNPQUVWXYZ./", 3, 7); const en = sc.encode(orig); writeln("Encoded: ", en); writeln("Decoded: ", sc.decode(en));
}</lang>
Dictionary-Based Version
<lang d>import std.stdio, std.string, std.algorithm, std.regex, std.array, std.range, std.typecons;
immutable string[const string] val2key, key2val;
static this() pure /*nothrow @safe*/ {
immutable aa = ["A":"30", "B":"31", "C":"32", "D":"33", "E":"5", "F":"34", "G":"35", "H":"0", "I":"36", "J":"37", "K":"38", "L":"2", "M":"4", ".":"78", "N":"39", "/":"79", "O":"1", "0":"790", "P":"70", "1":"791", "Q":"71", "2":"792", "R":"8", "3":"793", "S":"6", "4":"794", "T":"9", "5":"795", "U":"72", "6":"796", "V":"73", "7":"797", "W":"74", "8":"798", "X":"75", "9":"799", "Y":"76", "Z":"77"]; val2key = aa; key2val = aa.byKeyValue.map!(t => tuple(t.value, t.key)).assocArray;
}
string encode(in string s) pure /*nothrow*/ @safe {
return s.toUpper.split("").map!(c => val2key.get(c, "")).join;
}
string decode(in string s) /*pure nothrow*/ @safe {
return s.matchAll("79.|3.|7.|.").map!(g => key2val.get(g[0], "")).join;
}
void main() @safe {
immutable s = "One night-it was on the twentieth of March, 1888-I was returning"; s.encode.writeln; s.encode.decode.writeln;
}</lang>
- Output:
139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
F#
<lang fsharp> (* Encode and Decode using StraddlingCheckerboard Nigel Galloway May 15th., 2017
- )
type G={n:char;i:char;g:System.Collections.Generic.Dictionary<(char*char),string>;e:System.Collections.Generic.Dictionary<char,string>}
member G.encode n=n|>Seq.map(fun n->if (n='/') then G.e.['/']+string n else match (G.e.TryGetValue(n)) with |(true,n)->n|(false,_)->G.e.['/']+string n) member G.decode n = let rec fn n = seq{ if not (Seq.isEmpty n) then match (match Seq.head n with |g when g=G.n||g=G.i->(G.g.[(g,(Seq.item 1 n))],(Seq.skip 2 n))|g->(G.g.[('/',g)],(Seq.tail n))) with |(a,b) when a="/"->yield string (Seq.head b); yield! fn (Seq.tail b) |(a,b) ->yield a; yield! fn b } fn n
let G n i g e l z=
let a = new System.Collections.Generic.Dictionary<(char*char),string>() let b = new System.Collections.Generic.Dictionary<char,string>() Seq.iter2 (fun ng gn->a.[('/' ,char ng)]<-string gn;b.[gn]<-ng) (List.except [n;i] z) g Seq.iter2 (fun ng gn->a.[(char n,char ng)]<-string gn;b.[gn]<-n+ng) z e Seq.iter2 (fun ng gn->a.[(char i,char ng)]<-string gn;b.[gn]<-i+ng) z l {n=char n;i=char i;g=a;e=b}
</lang>
- Output:
- Output:
<lang fsharp> let N = G "2" "6" "ETAONRIS" "BCDFGHJKLM" "PQ/UVWXYZ." ["0";"1";"2";"3";"4";"5";"6";"7";"8";"9"] N.decode "450582425181653945125016505180125423293721256216286286288653970163758524"|>Seq.iter(fun n->printf "%s" n);; //ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING N.encode "IN THE WINTER 1965 WE WERE HUNGRY JUST BARELY ALIVE"|>Seq.iter(fun n->printfn "%s" n);; //8562 125062 658510762 62162962662562 65062 6507062 256352476762 26639162 20370286762 3288640 N.decode "8562 125062 658510762 62162962662562 65062 6507062 256352476762 26639162 20370286762 3288640"|>Seq.iter(fun n->printf "%s" n);; //IN THE WINTER 1965 WE WERE HUNGRY JUST BARELY ALIVE </lang>
Go
<lang go>package main
import (
"fmt" "strings"
)
func main() {
key := ` 8752390146 ET AON RIS
5BC/FGHJKLM 0PQD.VWXYZU`
p := "you have put on 7.5 pounds since I saw you." fmt.Println(p) c := enc(key, p) fmt.Println(c) fmt.Println(dec(key, c))
}
func enc(bd, pt string) (ct string) {
enc := make(map[byte]string) row := strings.Split(bd, "\n")[1:] r2d := row[2][:1] r3d := row[3][:1] for col := 1; col <= 10; col++ { d := string(row[0][col]) enc[row[1][col]] = d enc[row[2][col]] = r2d+d enc[row[3][col]] = r3d+d } num := enc['/'] delete(enc, '/') delete(enc, ' ') for i := 0; i < len(pt); i++ { if c := pt[i]; c <= '9' && c >= '0' { ct += num + string(c) } else { if c <= 'z' && c >= 'a' { c -= 'a'-'A' } ct += enc[c] } } return
}
func dec(bd, ct string) (pt string) {
row := strings.Split(bd, "\n")[1:] var cx [10]int for i := 1; i <= 10; i++ { cx[row[0][i]-'0'] = i } r2d := row[2][0]-'0' r3d := row[3][0]-'0' for i := 0; i < len(ct); i++ { var r int switch d := ct[i]-'0'; d { case r2d: r = 2 case r3d: r = 3 default: pt += string(row[1][cx[d]]) continue } i++ if b := row[r][cx[ct[i]-'0']]; b == '/' { i++ pt += string(ct[i]) } else { pt += string(b) } } return
}</lang>
- Output:
you have put on 7.5 pounds since I saw you. 01306592038080673955702555083069056649578462090130602 YOUHAVEPUTON7.5POUNDSSINCEISAWYOU.
Haskell
<lang haskell>import Data.Char import Data.Map
charToInt :: Char -> Int charToInt c = ord c - ord '0'
-- Given a string, decode a single character from the string. -- Return the decoded char and the remaining undecoded string. decodeChar :: String -> (Char,String) decodeChar ('7':'9':r:rs) = (r,rs) decodeChar ('7':r:rs) = ("PQUVWXYZ. " !! charToInt r, rs) decodeChar ('3':r:rs) = ("ABCDFGIJKN" !! charToInt r, rs) decodeChar (r:rs) = ("HOL MES RT" !! charToInt r, rs)
-- Decode an entire string. decode :: String -> String decode [] = [] decode st = let (c, s) = decodeChar st in c:decode s
-- Given a string, decode a single character from the string. -- Return the decoded char and the part of the encoded string -- used to encode that character. revEnc :: String -> (Char, String) revEnc enc = let (dec, rm) = decodeChar enc in (dec, take (length enc - length rm) enc)
ds :: String ds = ['0'..'9']
-- Decode all 1000 possible encodings of three digits and -- use results to construct map used to encode. encodeMap :: Map Char String encodeMap = fromList [ revEnc [d2,d1,d0] | d2 <- ds, d1 <- ds, d0 <- ds ]
-- Encode a single char using encoding map. encodeChar :: Char -> String encodeChar c = findWithDefault "" c encodeMap
-- Encode an entire string. encode :: String -> String encode st = concatMap encodeChar $ fmap toUpper st
-- Test by encoding, decoding, printing results. main = let orig = "One night-it was on the twentieth of March, 1888-I was returning"
enc = encode orig dec = decode enc in mapM_ putStrLn [ "Original: " ++ orig , "Encoded: " ++ enc , "Decoded: " ++ dec ]</lang>
- Output:
Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Icon and Unicon
<lang Icon>procedure main() StraddlingCheckerBoard("setup","HOLMESRTABCDFGIJKNPQUVWXYZ./", 3,7)
text := "One night. it was on the twentieth of March, 1888. I was returning" write("text = ",image(text)) write("encode = ",image(en := StraddlingCheckerBoard("encode",text))) write("decode = ",image(StraddlingCheckerBoard("decode",en))) end
procedure StraddlingCheckerBoard(act,text,b1,b2) static SCE,SCD case act of {
"setup" : { if (b1 < b2 < 10) & (*text = *cset(text) = 28) then { SCE := table("") SCD := table() esc := text[-1] # escape every text[(b1|b2)+1+:0] := " " # blanks uix := ["",b1,b2] # 1st position every c := text[1 + (i := 0 to *text-1)] do # build translation if c ~== " " then # skip blanks SCD[SCE[c] := SCE[map(c)] := uix[i/10+1]||(i%10) ] := c every c := !&digits do SCD[SCE[c] := SCE[esc] || c] := c delete(SCD,SCE[esc]) delete(SCE,esc) } else stop("Improper setup: ",image(text),", ",b1,", ",b2) } "encode" : { every (s := "") ||:= x := SCE[c := !text] return s } "decode" : { s := "" text ? until pos(0) do s ||:= \SCD[k := move(1 to 3)] return s } }
end</lang>
Output:
text = "One night. it was on the twentieth of March, 1888. I was returning" encode = "1395393635097836974306139905974539936590134430832079179879879878367430685972839363935" decode = "ONENIGHT.ITWASONTHETWENTIETHOFMARCH1888.IWASRETURNING"
J
Solution: <lang j>'Esc Stop'=: '/.' 'Nums Alpha'=: '0123456789';'ABCDEFGHIJKLMNOPQRSTUVWXYZ' Charset=: Nums,Alpha,Stop
escapenum=: (,@:((; Esc&,)&>) Nums) rplc~ ] NB. escape numbers unescapenum=: ((, ; ' '&,@])"1 0 Nums"_) rplc~ ] NB. unescape coded numbers (x is escape code, y is cipher) expandKeyatUV=: 0:`[`(1 #~ 2 + #@])} #inv ] makeChkBrd=: Nums , expandKeyatUV
chkbrd=: conjunction define
'uv key'=. n board=. uv makeChkBrd key select. m case. 0 do. NB. encode digits=. board 10&#.inv@i. escapenum y ' ' -.~ ,(":@{:"1 digits) ,.~ (1 1 0 2{":uv) {~ {."1 digits case. 1 do. NB. decode esc=. 0 chkbrd (uv;key) Esc NB. find code for Esc char tmp=. esc unescapenum esc,'0',y tmp=. ((":uv) ((-.@e.~ _1&|.) *. e.~) tmp) <;.1 tmp NB. box on chars from rows 0 2 3 idx=. (}. ,~ (1 1 0 2{":uv) ":@i. {.) each tmp NB. recreate indices for rows 0 2 3 idx=. ;(2&{. , [: ((0 1 $~ +:@#) #inv!.'1' ]) 2&}.) each idx NB. recreate indices for row 1 }.board {~ _2 (_&".)\ idx end.
)</lang> Example usage: <lang j> preprocess=: (#~ Charset e.~ ])@toupper NB. verb to compress out non-alphanumerics
chkbrdRC=: chkbrd (3 7;'HOLMESRTABCDFGIJKNPQUVWXYZ./') NB. define adverb by applying Rosetta Code key to chkbrd conjunction 0 chkbrdRC preprocess 'One night-it was on the twentieth of March, 1888-I was returning'
139539363509369743061399059745399365901344308320791798798798367430685972839363935
1 chkbrdRC 0 chkbrdRC preprocess 'One night-it was on the twentieth of March, 1888-I was returning'
ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING</lang> Or using the rules proposed by Util on the discussion page: <lang j> preprocess=: Stop&([`([: I. Charset -.@e.~ ])`]} toupper) NB. replace all non-alphanumerics with Stop
1 chkbrdRC 0 chkbrdRC preprocess 'One night-it was on the twentieth of March, 1888-I was returning'
ONE.NIGHT.IT.WAS.ON.THE.TWENTIETH.OF.MARCH..1888.I.WAS.RETURNING</lang>
Another method is to create a set of keys which correspond to the encoded letters in the alphabet. This allows for the relatively simple design of the encoding and decoding functions as they are essentially hash table lookups.
Solution: <lang j>NB. stops setcode alphabet NB. creates verbs encode and decode which change between unencoded text and lists of encoded numbers
setcode=: 3 :0
2 6 setcode y
alphabet=: y, ,":"0 i.10 stops=. x alphkeys=. (a: , ,&.> x) ([ -.~ [: , ,&.>/) i.10 esckey=. >(alphabet i. '/'){alphkeys numkeys=. esckey&,&.> i.10 keys=. alphkeys,numkeys
encode=: ([: ; keys {~ alphabet&i.) :. decode break=. </.~ i.@# - _1|. ([: >/\.&.|. e.&stops) + _1|.2*esckey&E. decode=: (alphabet {~ keys i. break f.) :. encode i.0 0 )</lang>
Example usage: <lang j> 3 7 setcode 'HOLMESRTABCDFGIJKNPQUVWXYZ./'
preprocess=: (#~ alphabet e.~ ])@toupper ,":"0 encode message=: preprocess 'One night-it was on the twentieth of March, 1888-I was returning'
139539363509369743061399059745399365901344308320791798798798367430685972839363935
decode encode message
ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
]s=. ((10|+) 0 4 5 2$~$)&.encode message NB. scramble by taking a modular sum with 0 4 5 2 while encoded
OWVKRNEOAMTMXROWOHTMTMTROTQ4SEMRRLRZLVSTTLLOROMHALSFOHECMRWESWEE
((10|-) 0 4 5 2$~$)&.encode s
ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING</lang>
Java
<lang java>import java.util.HashMap; import java.util.Map; import java.util.regex.*;
public class StraddlingCheckerboard {
final static String[] keyvals = {"H:0", "O:1", "L:2", "M:4", "E:5", "S:6", "R:8", "T:9", "A:30", "B:31", "C:32", "D:33", "F:34", "G:35", "I:36", "J:37", "K:38", "N:39", "P:70", "Q:71", "U:72", "V:73", "W:74", "X:75", "Y:76", "Z:77", ".:78", "/:79", "0:790", "1:791", "2:792", "3:793", "4:794", "5:795", "6:796", "7:797", "8:798", "9:799"};
final static Map<String, String> val2key = new HashMap<>(); final static Map<String, String> key2val = new HashMap<>();
public static void main(String[] args) { for (String keyval : keyvals) { String[] kv = keyval.split(":"); val2key.put(kv[0], kv[1]); key2val.put(kv[1], kv[0]); } String enc = encode("One night-it was on the twentieth of March, " + "1888-I was returning"); System.out.println(enc); System.out.println(decode(enc)); }
static String encode(String s) { StringBuilder sb = new StringBuilder(); for (String c : s.toUpperCase().split("")) { c = val2key.get(c); if (c != null) sb.append(c); } return sb.toString(); }
static String decode(String s) { Matcher m = Pattern.compile("(79.|3.|7.|.)").matcher(s); StringBuilder sb = new StringBuilder(); while (m.find()) { String v = key2val.get(m.group(1)); if (v != null) sb.append(v); } return sb.toString(); }
}</lang>
139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
JavaScript
<lang javascript><script> var alphabet=new Array("ESTONIA R","BCDFGHJKLM","PQUVWXYZ./") // scramble alphabet as you wish var prefixes=new Array("",alphabet[0].indexOf(" "),alphabet[0].lastIndexOf(" "))
function straddle(message){
var out="" message=message.toUpperCase() message=message.replace(/([0-9])/g,"/$1") // dumb way to escape numbers for(var i=0;i<message.length;i++){ var chr=message[i]
if(chr==" ")continue for(var j=0;j<3;j++){ var k=alphabet[j].indexOf(chr) if(k<0)continue out+=prefixes[j].toString()+k } if(chr=="/")out+=message[++i]
} return out
}
function unstraddle(message){
var out="" var n,o for(var i=0;i<message.length;i++){
n=message[i]*1
switch(n){
case prefixes[1]: o=alphabet[1][message[++i]];break case prefixes[2]: o=alphabet[2][message[++i]];break default: o=alphabet[0][n] } o=="/"?out+=message[++i]:out+=o
} return out
}
str="One night-it was on the twentieth of March, 1888-I was returning." document.writeln(str) document.writeln(straddle(str)) document.writeln(unstraddle(straddle(str))) </script></lang>
Output:
One night-it was on the twentieth of March, 1888-I was returning. 34045747525284613427502840425027537379697175891898898898584619028294547488 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING.
Julia
Unlike the precomputed table versions, this version takes a 30-character string specifying the 3 rows of the checkerboard as an argument, recomputing the lookup table each run, which allows easier changes of keys without modifying the code. <lang julia> function straddlingcheckerboard(board, msg, doencode)
lookup = Dict() reverselookup = Dict() row2 = row3 = slash = -1 function encode(x) s = "" for ch in replace(replace(uppercase(x), r"([01-9])", s";=;\1"), r";=;", slash) c = string(ch) if haskey(lookup, c) s *= lookup[c] elseif contains("0123456789", c) s *= c end end s end function decode(x) s = "" i = 1 while i <= length(x) c = string(x[i]) if haskey(reverselookup, c) s *= reverselookup[c] i += 1 else if "$c$(x[i+1])" == slash s *= string(x[i+2]) i += 3 else s *= reverselookup["$c$(x[i+1])"] i += 2 end end end s end for (i,c) in enumerate(board) c = string(c) if c == " " if row2 == -1 row2 = i-1 else row3 = i-1 end else if i < 11 lookup[c] = "$(i-1)"; reverselookup["$(i-1)"] = c elseif i < 21 lookup[c] = "$row2$(i-11)"; reverselookup["$row2$(i-11)"] = c else lookup[c] = "$row3$(i-21)"; reverselookup["$row3$(i-21)"] = c end if c == "/" slash = lookup[c] end end end doencode ? encode(msg) : decode(msg)
end
btable = "ET AON RISBCDFGHJKLMPQ/UVWXYZ." message = "Thecheckerboardcakerecipespecifies3largeeggsand2.25cupsofflour." encoded = straddlingcheckerboard(btable, message, true) decoded = straddlingcheckerboard(btable, encoded, false) println("Original: $message\nEncoded: $encoded\nDecoded: $decoded") </lang>
- Output:
Original: Thecheckerboardcakerecipespecifies3largeeggsand2.25cupsofflour. Encoded: 125021250212707204372221327070218600960021823809623283724002424935226226962262521636094232328463769 Decoded: THECHECKERBOARDCAKERECIPESPECIFIES3LARGEEGGSAND2.25CUPSOFFLOUR.
Kotlin
<lang scala>// version 1.2.0
val board = "ET AON RISBCDFGHJKLMPQ/UVWXYZ." val digits = "0123456789" val rows = " 26" val escape = "62" val key = "0452"
fun encrypt(message: String): String {
val msg = message.toUpperCase() .filter { (it in board || it in digits) && it !in " /" } val sb = StringBuilder() for (c in msg) { val idx = board.indexOf(c) if (idx > -1) { val row = idx / 10 val col = idx % 10 sb.append(if (row == 0) "$col" else "${rows[row]}$col") } else { sb.append("$escape$c") } } val enc = sb.toString().toCharArray() for ((i, c) in enc.withIndex()) { val k = key[i % 4] - '0' if (k == 0) continue val j = c - '0' enc[i] = '0' + ((j + k) % 10) } return String(enc)
}
fun decrypt(encoded: String): String {
val enc = encoded.toCharArray() for ((i, c) in enc.withIndex()) { val k = key[i % 4] - '0' if (k == 0) continue val j = c - '0' enc[i] = '0' + if (j >= k) (j - k) % 10 else (10 + j - k) % 10 } val len = enc.size val sb = StringBuilder() var i = 0 while (i < len) { val c = enc[i] val idx = rows.indexOf(c) if (idx == -1) { val idx2 = c - '0' sb.append(board[idx2]) i++ } else if ("$c${enc[i + 1]}" == escape) { sb.append(enc[i + 2]) i += 3 } else { val idx2 = idx * 10 + (enc[i + 1] - '0') sb.append(board[idx2]) i += 2 } } return sb.toString()
}
fun main(args: Array<String>) {
val messages = listOf( "Attack at dawn", "One night-it was on the twentieth of March, 1888-I was returning", "In the winter 1965/we were hungry/just barely alive", "you have put on 7.5 pounds since I saw you.", "The checkerboard cake recipe specifies 3 large eggs and 2.25 cups of flour." ) for (message in messages) { val encrypted = encrypt(message) val decrypted = decrypt(encrypted) println("\nMessage : $message") println("Encrypted : $encrypted") println("Decrypted : $decrypted") }
}</lang>
- Output:
Message : Attack at dawn Encrypted : 3565257935743007 Decrypted : ATTACKATDAWN Message : One night-it was on the twentieth of March, 1888-I was returning Encrypted : 495786945533698149645468540384645875238925776668221480708005915367278976 Decrypted : ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING Message : In the winter 1965/we were hungry/just barely alive Encrypted : 89645417896270736648201450026959060839767024608116557470618482160 Decrypted : INTHEWINTER1965WEWEREHUNGRYJUSTBARELYALIVE Message : you have put on 7.5 pounds since I saw you. Encrypted : 61983605685800834914704829124087264189730245691940889 Decrypted : YOUHAVEPUTON7.5POUNDSSINCEISAWYOU. Message : The checkerboard cake recipe specifies 3 large eggs and 2.25 cups of flour. Encrypted : 160225770664742408892673362274738052905225343251668487244454469139746678907466041088039436848815704 Decrypted : THECHECKERBOARDCAKERECIPESPECIFIES3LARGEEGGSAND2.25CUPSOFFLOUR.
Lua
<lang lua> local brd = { "HOL MES RT", "ABCDFGIJKN", "PQUVWXYZ./" } local dicE, dicD, s1, s2 = {}, {}, 0, 0
function dec( txt )
local i, numb, s, t, c = 1, false while( i < #txt ) do c = txt:sub( i, i ) if not numb then if tonumber( c ) == s1 then i = i + 1; s = string.format( "%d%s", s1, txt:sub( i, i ) ) t = dicD[s] elseif tonumber( c ) == s2 then i = i + 1; s = string.format( "%d%s", s2, txt:sub( i, i ) ) t = dicD[s] else t = dicD[c] end if t == "/" then numb = true else io.write( t ) end else io.write( c ) numb = false end i = i + 1 end print()
end function enc( txt )
local c for i = 1, #txt do c = txt:sub( i, i ) if c >= "A" and c <= "Z" then io.write( dicE[c] ) elseif c >= "0" and c <= "9" then io.write( string.format( "%s%s", dicE["/"], c ) ) end end print()
end function createDictionaries()
for i = 1, 10 do c = brd[1]:sub( i, i ) if c == " " then if s1 == 0 then s1 = i - 1 elseif s2 == 0 then s2 = i - 1 end else dicE[c] = string.format( "%d", i - 1 ) dicD[string.format( "%d", i - 1 )] = c end end for i = 1, 10 do dicE[brd[2]:sub( i, i )] = string.format( "%d%d", s1, i - 1 ) dicE[brd[3]:sub( i, i )] = string.format( "%d%d", s2, i - 1 ) dicD[string.format( "%d%d", s1, i - 1 )] = brd[2]:sub( i, i ) dicD[string.format( "%d%d", s2, i - 1 )] = brd[3]:sub( i, i ) end
end function enterText()
createDictionaries() io.write( "\nEncrypt or Decrypt (E/D)? " ) d = io.read() io.write( "\nEnter the text:\n" ) txt = io.read():upper() if d == "E" or d == "e" then enc( txt ) elseif d == "D" or d == "d" then dec( txt ) end
end -- entry point enterText() </lang>
- Output:
Lua 5.3.3 Copyright (C) 1994-2016 Lua.org, PUC-Rio > dofile "straddling.lua" Encrypt or Decrypt (E/D)? e Enter the text: One night-it was on the twentieth of March, 1888-I was returning 139539363509369743061399059745399365901344308320791798798798367430685972839363935 > dofile "straddling.lua" Encrypt or Decrypt (E/D)? d Enter the text: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
M2000 Interpreter
<lang M2000 Interpreter> module Straddling_checkerboard { function encrypt$(message$, alphabet) { message$=filter$(ucase$(message$),"-/,. ") def num1, num2 num1=instr(alphabet#val$(0)," ") num2=instr(alphabet#val$(0)," ", num1+1)-1 num1-- escapenum=instr(alphabet#val$(2),"/")-1 escapenum1=instr(alphabet#val$(2),".")-1 num0=-10 num10=num1*10-20 num20=num2*10-30 numbers=(escapenum+num2*10)*10 numbers1=(escapenum1+num2*10)*10 boardrow=each(alphabet) cipherkey$="0123456789" : while boardrow :cipherkey$+=array$(boardrow) :end while encoded$="" for i=1 to len(message$) n=instr(cipherkey$, mid$(message$,i,1))-1 if n<10 then n+=if(random(10)<5->numbers, numbers1) else.if n<20 then n+=num0 else.if n<30 then n+=num10 else n+=num20 end if encoded$+=str$(n,"") next =encoded$ } function decrypt$(encoded$, alphabet) { def num1, num2 num1=instr(alphabet#val$(0)," ") num2=instr(alphabet#val$(0)," ", num1+1)-1 num1-- escapenum=instr(alphabet#val$(2),"/")-1 escapenum1=instr(alphabet#val$(2),".")-1 def i=1, decoded$ j=len(encoded$)+1 while i<j m=val(mid$(encoded$,i,1)) if m=num1 then decoded$+=mid$(alphabet#val$(1), val(mid$(encoded$,i+1,1))+1,1) i++ else.if m=num2 then if i+1<j then mm=val(mid$(encoded$,i+1,1)) if mm=escapenum or mm=escapenum1 then decoded$+=mid$(encoded$,i+2,1) i+=2 else decoded$+=mid$(alphabet#val$(2), val(mid$(encoded$,i+1,1))+1,1) i++ end if else decoded$+=mid$(alphabet#val$(2), val(mid$(encoded$,i+1,1))+1,1) i++ end if else decoded$+=mid$(alphabet#val$(0), m+1,1) end if i++ end while =decoded$ } Module DisplayBoard (alphabet, &Doc$){ num1=instr(alphabet#val$(0)," ") num2=instr(alphabet#val$(0)," ", num1+1)-1 num1-- escapenum=instr(alphabet#val$(2),"/")-1 escapenum1=instr(alphabet#val$(2),".")-1 \\ display straddling checkerboard checkerboard =cons(("0123456789",),alphabet) labels=(" "," ",str$(num1,""), str$(num2,"")) disp=each(checkerboard) while disp Doc$=labels#val$(disp^)+" "+array$(disp)+{ } end while } Document Doc$ Const nl$={ } Function OnePad$(Message$, PadSerial, n=1) { x=random(!PadSerial) ' push old seed, set the new one encoded$="" for i=1 to len(Message$) encoded$+=str$((val(mid$(Message$,i,1))+10+n*random(1, 10))mod 10,"") next i x=random(!) ' restore old seed =encoded$ } \\ select a random alphabet select case random(1,3) case 1 alphabet=("ESTONIAR ","BCDFGHJKLM","/PQUVWXYZ.") : Doc$="First "+nl$ case 2 alphabet=("ET AON RIS","BCDFGHJKLM","PQ/UVWXYZ.") : Doc$="Second"+nl$ case 3 alphabet=("ESTONIAR ","BCDFGHJKLM","PQU.VWXYZ/") : Doc$="Third"+nl$ end select DisplayBoard alphabet, &Doc$ msg$="One night-it was on the twentieth of March, 1888-I was returning" Doc$= "original message:"+nl$ Doc$= msg$+nl$ Doc$= "encrypted message:"+nl$ crypt$=encrypt$(msg$, alphabet) Doc$=crypt$+nl$ serial=random(1234567,9345678) Doc$= "encrypted message using one pad using serial:"+str$(serial)+nl$ crypt$=OnePad$(crypt$, serial) Doc$=crypt$+nl$ Doc$= "decrypted message using one pad:"+nl$ crypt$=OnePad$(crypt$, serial,-1) Doc$=crypt$+nl$ Doc$= "decrypted message:"+nl$ Doc$=decrypt$(crypt$, alphabet) Print #-2, Doc$ ' render to console using new lines codes from Doc$ Clipboard Doc$ } Straddling_checkerboard </lang>
- Output:
First 0123456789 ESTONIAR 8 BCDFGHJKLM 9 /PQUVWXYZ. original message: One night-it was on the twentieth of March, 1888-I was returning encrypted message: 340458485252956134285029504250285383896781859019989989985956170293745484 encrypted message using one pad using serial: 7745037 811354381526409435575275634030693156335135381796263056259799033307312819 decrypted message using one pad: 340458485252956134285029504250285383896781859019989989985956170293745484 decrypted message: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING Second 0123456789 ET AON RIS 2 BCDFGHJKLM 6 PQ/UVWXYZ. original message: One night-it was on the twentieth of March, 1888-I was returning encrypted message: 450582425181653945125016505180125423293721256216986986288653970163758524 encrypted message using one pad using serial: 8485713 339360039726873741044731817004082441136155821888897367354417518371636266 decrypted message using one pad: 450582425181653945125016505180125423293721256216986986288653970163758524 decrypted message: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Nim
I used the same example as in the Go solution (and, fortunately, got the same result). <lang Nim>import strutils, tables
const
FullStop = '.' Escape = '/'
type Checkerboard = object
encryptTable: Table[char, string] decryptTable: Table[string, char]
proc initCheckerboard(digits: string; row1, row2, row3: string): Checkerboard =
## Initialize a checkerboard with given digits in row 0 and the following given rows. ## No sanity check is performed.
var rowChars: seq[char] # The two characters to use to identify rows 2 and 3.
# Process row 1. for col, ch in row1: if ch == ' ': rowChars.add digits[col] else: result.encryptTable[ch] = $digits[col] if rowChars.len != 2: raise newException(ValueError, "expected two blank spots in first letter row.")
# Add rows 2 and 3. for col, ch in row2: result.encryptTable[ch] = rowChars[0] & digits[col] for col, ch in row3: result.encryptTable[ch] = rowChars[1] & digits[col] if Escape notin result.encryptTable: raise newException(ValueError, "missing Escape character.")
# Build decrypt table from encrypt table. for c, s in result.encryptTable.pairs: result.decryptTable[s] = c
proc encrypt(board: Checkerboard; message: string): string =
## Encrypt a string.
let message = message.toUpperAscii for ch in message: case ch of 'A'..'Z', FullStop, Escape: result.add board.encryptTable[ch] of '0'..'9': result.add board.encryptTable[Escape] result.add ch else: discard # Ignore other characters.
proc raiseError() =
## Raise a ValueError to signal a corrupt message. raise newException(ValueError, "corrupt message")
proc decrypt(board: Checkerboard; message: string): string =
## Decrypt a message.
var escaped = false # Escape char previously encountered. var str = "" # Current sequence of characters (contains 0, 1 or 2 chars).
for ch in message: if ch notin '0'..'9': raiseError()
if escaped: # Digit is kept as is. result.add ch escaped = false else: # Try to decrypt this new digit. str.add ch if str in board.decryptTable: let c = board.decryptTable[str] if c == Escape: escaped = true else: result.add c str.setLen(0) elif str.len == 2: # Illegal combination of two digits. raiseError()
when isMainModule:
let board = initCheckerboard("8752390146", "ET AON RIS", "BC/FGHJKLM", "PQD.VWXYZU") let message = "you have put on 7.5 pounds since I saw you." echo "Message: ", message let crypted = board.encrypt(message) echo "Crypted: ", crypted echo "Decrypted: ", board.decrypt(crypted)</lang>
- Output:
Message: you have put on 7.5 pounds since I saw you. Crypted: 01306592038080673955702555083069056649578462090130602 Decrypted: YOUHAVEPUTON7.5POUNDSSINCEISAWYOU.
Perl
<lang perl>use strict; use warnings; use feature 'say'; use List::Util <min max>;
my(%encode,%decode,@table);
sub build {
my($u,$v,$alphabet) = @_; my(@flat_board,%p2c,%c2p); my $numeric_escape = '/';
@flat_board = split , uc $alphabet; splice @flat_board, min($u,$v), 0, undef; splice @flat_board, max($u,$v), 0, undef;
push @table, [' ', 0..9]; push @table, [' ', map { defined $_ ? $_ : ' '} @flat_board[ 0 .. 9] ]; push @table, [$u, @flat_board[10 .. 19]]; push @table, [$v, @flat_board[20 .. 29]];
my @nums = my @order = 0..9; push @nums, (map { +"$u$_" } @order), map { +"$v$_" } @order;
@c2p{@nums} = @flat_board; for (keys %c2p) { delete $c2p{$_} unless defined $c2p{$_} } @p2c{values %c2p} = keys %c2p; $p2c{$_} = $p2c{$numeric_escape} . $_ for 0..9; while (my ($k, $v) = each %p2c) { $encode{$k} = $v; $decode{$v} = $k unless $k eq $numeric_escape; }
}
sub decode {
my($string) = @_; my $keys = join '|', keys %decode; $string =~ s/($keys)/$decode{$1}/gr;
}
sub encode {
my($string) = uc shift; $string =~ s#(.)#$encode{$1} // $encode{'.'}#ger;
}
my $sc = build(3, 7, 'HOLMESRTABCDFGIJKNPQUVWXYZ./'); say join ' ', @$_ for @table; say ; say 'Original: ', my $original = 'One night-it was on the twentieth of March, 1888-I was returning'; say 'Encoded: ', my $en = encode($original); say 'Decoded: ', decode($en);</lang>
- Output:
0 1 2 3 4 5 6 7 8 9 H O L M E S R T 3 A B C D F G I J K N 7 P Q U V W X Y Z . / Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 13957839363509783697874306781397890578974539936590781347843083207878791798798798783678743067885972839363935 Decoded: ONE.NIGHT.IT.WAS.ON.THE.TWENTIETH.OF.MARCH..1888.I.WAS.RETURNING
Phix
<lang Phix>function read_table(string cb)
sequence encode = repeat("",128), decode = repeat(0,128), row = {0} if length(cb)!=30 then crash("table wrong length") end if for i=1 to 30 do integer c = cb[i] if c=' ' then row &= i-1 else integer code = row[floor((i-1)/10)+1]*10+mod((i-1),10) encode[c] = sprintf("%d",code) decode[code+1] = c end if end for return {encode, decode}
end function
function encipher(sequence encode, string in, bool strip=false)
string out = "" for i=1 to length(in) do integer c = upper(in[i]), code if c>='0' and c<='9' then out &= encode['.']&c elsif c>='A' and c<='Z' then out &= encode[c] elsif not strip or c='/' then -- (see note) out &= encode['/'] end if end for return out
end function
function decipher(sequence decode, string in, bool strip=false)
string out = "" integer i = 1 while i<=length(in) do integer c = in[i]-'0'+1 if decode[c]=0 then i += 1 c = (c-1)*10+in[i]-'0'+1 end if integer d = decode[c] if d='.' then i += 1 d = in[i] elsif d='/' and not strip then -- (see note) d = ' ' end if out &= d i += 1 end while return out
end function
constant cb = "ET AON RIS"&
"BCDFGHJKLM"& "PQ/UVWXYZ."
sequence {encode,decode} = read_table(cb)
-- Note there is a subtle difference in space handling, to exactly match other outputs try -- {encode,decode} = read_table("HOL MES RTABCDFGIJKNPQUVWXYZ/.") instead of -- {encode,decode} = read_table("HOL MES RTABCDFGIJKNPQUVWXYZ./"), and -- {encode,decode} = read_table("ET AON RISBCDFGHJKLMPQ.UVWXYZ/") instead of -- {encode,decode} = read_table("ET AON RISBCDFGHJKLMPQ/UVWXYZ.")
string msg = "In the winter 1965/we were hungry/just barely alive" printf(1,"message: %s\n", {msg}) string enc = encipher(encode, msg),
dec = decipher(decode, enc)
printf(1,"encoded: %s\n", {enc}) printf(1,"decoded: %s\n", {dec})
printf(1,"\nNo spaces:\n") enc = encipher(encode, msg, true) dec = decipher(decode, enc, true) printf(1,"encoded: %s\n", {enc}) printf(1,"decoded: %s\n", {dec})</lang>
- Output:
message: In the winter 1965/we were hungry/just barely alive encoded: 85621250626585107626916996966956265062650706225635247676226639162203702867623288640 decoded: IN THE WINTER 1965 WE WERE HUNGRY JUST BARELY ALIVE No spaces: encoded: 851250658510769169969669562650650702563524767622663912037028673288640 decoded: INTHEWINTER1965/WEWEREHUNGRY/JUSTBARELYALIVE
PHP
<lang php>$key2val = ["A"=>"30", "B"=>"31", "C"=>"32", "D"=>"33", "E"=>"5", "F"=>"34", "G"=>"35",
"H"=>"0", "I"=>"36", "J"=>"37", "K"=>"38", "L"=>"2", "M"=>"4", "."=>"78", "N"=>"39", "/"=>"79", "O"=>"1", "0"=>"790", "P"=>"70", "1"=>"791", "Q"=>"71", "2"=>"792", "R"=>"8", "3"=>"793", "S"=>"6", "4"=>"794", "T"=>"9", "5"=>"795", "U"=>"72", "6"=>"796", "V"=>"73", "7"=>"797", "W"=>"74", "8"=>"798", "X"=>"75", "9"=>"799", "Y"=>"76", "Z"=>"77"];
$val2key = array_flip($key2val);
function encode(string $s) : string {
global $key2val; $callback = function($c) use ($key2val) { return $key2val[$c] ?? ; };
return implode(array_map($callback, str_split(strtoupper($s))));
}
function decode(string $s) : string {
global $val2key;
$callback = function($c) use ($val2key) { return $val2key[$c] ?? ; }; preg_match_all('/79.|7.|3.|./', $s, $m); return implode(array_map($callback, $m[0]));
}
function main($s) {
$encoded = encode($s); echo $encoded; echo "\n"; echo decode($encoded);
}
main('One night-it was on the twentieth of March, 1888-I was returning');</lang>
139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
PicoLisp
<lang PicoLisp>(de *Straddling
(NIL "H" "O" "L" NIL "M" "E" "S" NIL "R" "T") ("3" "A" "B" "C" "D" "F" "G" "I" "J" "K" "N") ("7" "P" "Q" "U" "V" "W" "X" "Y" "Z" "." "/") ("79" "0" "1" "2" "3" "4" "5" "6" "7" "8" "9") )
(de straddle (Str)
(pack (mapcar '((C) (pick '((L) (and (index C (cdr L)) (cons (car L) (dec @)) ) ) *Straddling ) ) (chop (uppc Str)) ) ) )
(de unStraddle (Str)
(pack (make (for (L (chop Str) L) (let C (pop 'L) (setq C (if (assoc C *Straddling) (get (cdr @) (inc (format (pop 'L)))) (get (cdar *Straddling) (inc (format C))) ) ) (link (if (= "/" C) (pop 'L) C)) ) ) ) ) )</lang>
Output:
: (straddle "One night-it was on the twentieth of March, 1888-I was returning") -> "139539363509369743061399059745399365901344308320791798798798367430685972839363935" : (unStraddle @) -> "ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING"
PureBasic
<lang purebasic>Procedure.s encrypt_SC(originalText.s, alphabet.s, blank_1, blank_2)
Static notEscape.s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ." Protected preDigit_1.s = Str(blank_1), preDigit_2.s = Str(blank_2) Protected i, index, curChar.s, escapeChar.s, outputText.s Protected NewMap cipher.s() ;build cipher reference alphabet = UCase(alphabet) For i = 1 To 28 curChar = Mid(alphabet, i, 1) If Not FindString(notEscape, curChar) escapeChar = curChar EndIf Select i Case 1 To 8 If index = blank_1 Or index = blank_2: index + 1: EndIf ;adjust index for blank cipher(curChar) = Str(index) index + 1 Case 9 To 18 cipher(curChar) = preDigit_1 + Str(i - 9) Case 19 To 28 cipher(curChar) = preDigit_2 + Str(i - 19) EndSelect Next For i = 0 To 9: cipher(Str(i)) = cipher(escapeChar) + Str(i): Next ;encrypt each character originalText = UCase(originalText) Protected length = Len(originalText) For i = 1 To length outputText + cipher(Mid(originalText, i, 1)) Next ProcedureReturn outputText
EndProcedure
Procedure.s decrypt_SC(cipherText.s, alphabet.s, blank_1, blank_2)
Static notEscape.s = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ." Protected preDigit_1.s = Str(blank_1), preDigit_2.s = Str(blank_2) Protected i, index, curChar.s, escapeCipher.s, outputText.s Protected NewMap cipher.s() ;build decipher reference alphabet = UCase(alphabet) For i = 1 To 28 curChar = Mid(alphabet, i, 1) Select i Case 1 To 8 If index = blank_1 Or index = blank_2: index + 1: EndIf ;adjust index for blank
cipher(Str(index)) = curChar index + 1 Case 9 To 18 cipher(preDigit_1 + Str(i - 9)) = curChar Case 19 To 28 cipher(preDigit_2 + Str(i - 19)) = curChar EndSelect If Not FindString(notEscape, curChar) escapeCipher = MapKey(cipher()) EndIf Next For i = 0 To 9: cipher(escapeCipher + Str(i)) = Str(i): Next ;decrypt each character Protected length = Len(cipherText) index = 1 While index <=length curChar = Mid(cipherText, index, 1) If curChar = preDigit_1 Or curChar = preDigit_2 curChar = Mid(cipherText, index, 2) If curChar = escapeCipher: curChar = Mid(cipherText, index, 3): EndIf EndIf outputText + cipher(curChar) index + Len(curChar) Wend ProcedureReturn outputText
EndProcedure
If OpenConsole()
Define message.s = "One night-it was on the twentieth of March, 1888-I was returning" Define cipher.s = "HOLMESRTABCDFGIJKNPQUVWXYZ./", encoded.s PrintN("Original: " + message) encoded = encrypt_SC(message, cipher, 3, 7) PrintN("encoded: " + encoded) PrintN("decoded: " + decrypt_SC(encoded, cipher, 3, 7)) Print(#CRLF$ + #CRLF$ + "Press ENTER to exit"): Input() CloseConsole()
EndIf</lang> Sample output:
Original: One night-it was on the twentieth of March, 1888-I was returning encoded: 13953936350936974306139905974539936590134430832079179879879836743068597 2839363935 decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Python
Partially based on the PicoLisp version: <lang python>T = [["79", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"],
["", "H", "O", "L", "", "M", "E", "S", "", "R", "T"], ["3", "A", "B", "C", "D", "F", "G", "I", "J", "K", "N"], ["7", "P", "Q", "U", "V", "W", "X", "Y", "Z", ".", "/"]]
def straddle(s):
return "".join(L[0]+T[0][L.index(c)] for c in s.upper() for L in T if c in L)
def unstraddle(s):
s = iter(s) for c in s: if c in [T[2][0], T[3][0]]: i = [T[2][0], T[3][0]].index(c) n = T[2 + i][T[0].index(s.next())] yield s.next() if n == "/" else n else: yield T[1][T[0].index(c)]
O = "One night-it was on the twentieth of March, 1888-I was returning" print "Encoded:", straddle(O) print "Decoded:", "".join(unstraddle(straddle(O)))</lang> Output:
Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Racket
Based in the PicoLisp version.
We store the straddling checkerboard in a structure, so it can be reused or changed for the different examples. The “constructor” transforms the lines of the checkboard into an internal representation. <lang Racket>#lang racket
(struct *straddling (header main original)
#:reflection-name 'straddling #:methods gen:custom-write [(define (write-proc board port mode) (write-string "#<straddling " port) (write (*straddling-original board) port) (write-string ">" port))])
(define string->vector (compose list->vector string->list))
(define (straddling . lines)
(define header-tail (reverse (for/fold ([rev-ret '()]) ([char (in-list (string->list (car lines)))] [i (in-naturals)]) (if (equal? char #\space) (cons (number->string i) rev-ret) rev-ret)))) (define main (list->vector (map string->vector (cons "0123456789" (map string-upcase lines))))) (define temporal-board (*straddling (list->vector (list* "?" "" header-tail)) main lines)) (define escape (straddling-encode-char #\/ temporal-board)) (*straddling (list->vector (list* escape "" header-tail)) main lines))</lang>
Now we define the functions to straddle and unstraddle the message. <lang Racket>(define (straddling-encode-char char board)
(or (for/or ([head (in-vector (*straddling-header board))] [line (in-vector (*straddling-main board))]) (let ([pos (vector-member char line)]) (if pos (string-append head (number->string pos)) #f))) ""))
(define (straddle message board)
(apply string-append (map (lambda (char) (if (or (equal? char #\space) (equal? char #\/)) "" (straddling-encode-char char board))) (string->list (string-upcase message)))))
(define (unstraddle message board)
(define char->string string) (define (straddling-decode-char str row) (vector-ref (vector-ref (*straddling-main board) row) (string->number str))) (list->string (reverse (let-values ([(row rev-ret) (for/fold ([row #f] ;row to read in multichar codes ;#f means start of new code [rev-ret '()]) ;result ([str (map char->string (string->list (string-upcase message)))]) (if (not row) (let ([pos (vector-member str (*straddling-header board))]) (if pos (values pos rev-ret) (values #f (cons (straddling-decode-char str 1) rev-ret)))) (let ([decoded (straddling-decode-char str row)]) (if (equal? decoded #\/) (values 0 rev-ret) (values #f (cons decoded rev-ret))))))]) (unless row ;check that last number was not missing rev-ret)))))</lang>
Two examples: <lang Racket>(define (test-straddling message board)
(let* ([encoded (straddle message board)] [decoded (unstraddle encoded board)]) (displayln board) (displayln message) (displayln encoded) (displayln decoded)))
(test-straddling "One night-it was on the twentieth of March, 1888-I was returning"
(straddling "HOL MES RT" "ABCDFGIJKN" "PQUVWXYZ./"))
(newline) (test-straddling "One night-it was on the twentieth of March, 1888-I was returning"
(straddling "ET AON RIS" "BCDFGHJKLM" "PQ/UVWXYZ."))</lang>
- Output:
#<straddling ("HOL MES RT" "ABCDFGIJKN" "PQUVWXYZ./")> One night-it was on the twentieth of March, 1888-I was returning 139539363509369743061399059745399365901344308320791798798798367430685972839363935 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING #<straddling ("ET AON RIS" "BCDFGHJKLM" "PQ/UVWXYZ.")> One night-it was on the twentieth of March, 1888-I was returning 450582425181653945125016505180125423293721256216286286288653970163758524 ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Raku
(formerly Perl 6)
The .trans method in Raku improves on Perl 5's tr/// by allowing multi-character translation tables.
We build the full table during .new, which simplifies .encode and .decode. <lang perl6>class Straddling_Checkerboard {
has @!flat_board; # 10x3 stored as 30x1 has $!plain2code; # full translation table, invertable has @!table; # Printable layout, like Wikipedia entry my $numeric_escape = '/'; my $exclude = /<-[A..Z0..9.]>/; # Omit the escape character
method display_table { gather { take ~ .list for @!table } };
method decode ( Str $s --> Str ) { $s.trans($!plain2code.antipairs); }
method encode ( Str $s, :$collapse? --> Str ) { my $replace = $collapse ?? !! '.'; $s.uc.subst( $exclude, $replace, :g ).trans($!plain2code); }
submethod BUILD ( :$alphabet, :$u where 0..9, :$v where 0..9 ) { die if $u == $v; die if $alphabet.comb.sort.join ne [~] flat './', 'A'..'Z';
@!flat_board = $alphabet.uc.comb; @!flat_board.splice( $u min $v, 0, Any ); @!flat_board.splice( $u max $v, 0, Any );
@!table = [ ' ',| [ 0 .. 9] ], [ ' ',|@!flat_board[ 0 .. 9].map: {.defined ?? $_ !! ' '} ], [ $u, |@!flat_board[10 .. 19] ], [ $v, |@!flat_board[20 .. 29] ];
my @order = 0..9; # This may be passed as a param in the future
my @nums = flat @order, @order.map({ +"$u$_" }), @order.map({ +"$v$_" });
my %c2p = @nums Z=> @!flat_board; %c2p{$_}:delete if %c2p{$_} eqv Any for keys %c2p; my %p2c = %c2p.invert; %p2c{$_} = %p2c{$numeric_escape} ~ $_ for 0..9; $!plain2code = [%p2c.keys] => [%p2c.values]; }
}
sub MAIN ( :$u = 3, :$v = 7, :$alphabet = 'HOLMESRTABCDFGIJKNPQUVWXYZ./' ) {
my Straddling_Checkerboard $sc .= new: :$u, :$v, :$alphabet; $sc.display_table;
for 0..1 -> $collapse { my $original = 'One night-it was on the twentieth of March, 1888-I was returning'; my $en = $sc.encode($original, :$collapse); my $de = $sc.decode($en); say ; say "Original: $original"; say "Encoded: $en"; say "Decoded: $de"; }
}</lang>
Output:
0 1 2 3 4 5 6 7 8 9 H O L M E S R T 3 A B C D F G I J K N 7 P Q U V W X Y Z . / Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 13957839363509783697874306781397890578974539936590781347843083207878791798798798783678743067885972839363935 Decoded: ONE.NIGHT.IT.WAS.ON.THE.TWENTIETH.OF.MARCH..1888.I.WAS.RETURNING Original: One night-it was on the twentieth of March, 1888-I was returning Encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
REXX
Extra coding was added to:
- allow the use of any table (specifiable on the invocation of the genCipher subroutine, the 5th line in the REXX program),
- no hard-coding of the location of blanks,
- no hard-coding or the numbered lines in the straddled checkerboard table,
- no hard-coding of the location of the escape character,
- support the usage of a blank in the 1st character (the top line of the table).
<lang rexx>/*REXX program uses the straddling checkerboard cipher to encrypt/decrypt a message. */ parse arg msg /*obtain optional message from the C.L.*/ if msg= then msg= 'One night-it was the twentieth of March, 1888-I was returning'
say 'plain text=' msg
call genCipher 'et aon ris', 'bcdfghjklm', 'pq/uvwxyz.' /*build the cipher (board)*/ enc= encrypt(msg); say ' encrypted=' enc /*encrypt message and show encryption. */ dec= decrypt(enc); say ' decrypted=' dec /*decrypt " " " decryption. */ exit 0 /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ genCipher: @.=; arg @..,two,three; z= -1; @.z= @.. /*build top row of cipher.*/
_= pos(' ', @.. ) - 1; @._= two /* " 2nd " " " */ _= pos(' ', @.., _+2) - 1; @._= three /* " 3rd " " " */ do j=0 for 9; @..= @.. || @.j /*construct a table for fast searching.*/ if @.j\== then @.r= @.r || j _= pos('/', @.j) /*is the escape character in this row? */ if _\==0 then @.dig= j || (_-1) /*define " " for numerals.*/ end /*j*/ @..= space(@.., 0); return /*purify the table of encryptable chars*/
/*──────────────────────────────────────────────────────────────────────────────────────*/ encrypt: procedure expose @.; arg !,,$ /*$: output (encrypted text) so far.*/
do j=1 for length(!) /*process each of the plain─text chars.*/ x= substr(!, j, 1) /*obtain a message char to be encrypted*/ if datatype(x, 'W') then do; $= $ || @.dig || x; iterate; end /*numeral?*/ if pos(x, @..)==0 then iterate /*Not one of the allowable chars? Skip*/ do k=-1 for 10; y= pos(x, @.k) /*traipse thru rows, looking for match.*/ if y==0 then iterate /*Not in this row? Then keep looking.*/ z= k; if z==-1 then z= /*construct the index of the cypher row*/ $= $ || z || (y-1); leave /*add an encrypted character to output.*/ end /*k*/ end /*j*/; return $
/*──────────────────────────────────────────────────────────────────────────────────────*/ decrypt: procedure expose @.; parse arg !,,$ /*$: output (decrypted text) so far.*/
do j=1 to length(!); rw= -1 /*process each of the encypted numbers.*/ x= substr(!,j,1) /*obtain a message char to be decrypted*/ if substr(!,j,2)==@.dig then do; j= j+2; $= $ || substr(!, j, 1); iterate; end if pos(x, @.r)\==0 then do; j= j+1; rw=x; x=substr(!, j, 1); end $= $ || substr(@.rw, x+1, 1) /*add a character to decrypted message.*/ end /*j*/; return $</lang>
- output when using the default input:
plain text= One night-it was the twentieth of March, 1888-I was returning encrypted= 4505824251816539125016505180125423293721256216286286288653970163758524 decrypted= ONENIGHTITWASTHETWENTIETHOFMARCH1888IWASRETURNING
Ruby
<lang ruby>class StraddlingCheckerboard
EncodableChars = "A-Z0-9." SortedChars = " ./" + [*"A".."Z"].join def initialize(board = nil) if board.nil? # create a new random board rest = "BCDFGHJKLMPQUVWXYZ/.".chars.shuffle @board = [" ESTONIAR".chars.shuffle, rest[0..9], rest[10..19]] elsif board.chars.sort.join == SortedChars @board = board.chars.each_slice(10).to_a else raise ArgumentError, "invalid #{self.class}: #{board}" end # find the indices of the first row blanks @row_labels = @board[0].each_with_index.select {|v, i| v == " "}.map {|v,i| i} @mapping = {} @board[0].each_with_index {|char, idx| @mapping[char] = idx.to_s unless char == " "} @board[1..2].each_with_index do |row, row_idx| row.each_with_index do |char, idx| @mapping[char] = "%d%d" % [@row_labels[row_idx], idx] end end end def encode(message) msg = message.upcase.delete("^#{EncodableChars}") msg.chars.inject("") do |crypt, char| crypt << (char =~ /[0-9]/ ? @mapping["/"] + char : @mapping[char]) end end def decode(code) msg = "" tokens = code.chars until tokens.empty? token = tokens.shift itoken = token.to_i unless @row_labels.include?(itoken) msg << @board[0][itoken] else token2 = tokens.shift if @mapping["/"] == token + token2 msg << tokens.shift else msg << @board[1+@row_labels.index(itoken)][token2.to_i] end end end msg end def to_s @board.inject("") {|res, row| res << row.join} end def inspect "#<%s board=%p, row_labels=%p, mapping=%p>" % [self.class, to_s, @row_labels, @mapping] end
end</lang>
The test suite <lang ruby>require 'test/unit' class StraddlingCheckerboardTest < Test::Unit::TestCase
def setup @msg = "One night-it was on the twentieth of March, 1888-I was returning" @expected = "ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING" end def test1 sc = StraddlingCheckerboard.new "ET AON RISBCDFGHJKLMPQ/UVWXYZ." code = sc.encode(@msg) plaintext = sc.decode(code) puts "using checkerboard: #{sc}" puts "original: #{@msg}" puts "encoded: #{code}" puts "decoded: #{plaintext}" assert_equal("450582425181653945125016505180125423293721256216286286288653970163758524", code) assert_equal(@expected, plaintext) end def test_board_with_space_in_first_char sc = StraddlingCheckerboard.new " RIOESN ATG./LXYBDKQMJUHWPVCFZ" code = sc.encode(@msg) plaintext = sc.decode(code) #p sc #puts "encoded: #{code}" #puts "decoded: #{plaintext}" assert_equal(@expected, plaintext) end def test_random_board sc = StraddlingCheckerboard.new plaintext = sc.decode(sc.encode(@msg)) assert_equal(@expected, plaintext) end def test_invalid_input assert_raise(ArgumentError) {StraddlingCheckerboard.new "ET ON RISBCDFGHJKLMPQ/UVWXYZ.!"} end
end</lang>
output
Run options: # Running tests: using checkerboard: ET AON RISBCDFGHJKLMPQ/UVWXYZ. original: One night-it was on the twentieth of March, 1888-I was returning encoded: 450582425181653945125016505180125423293721256216286286288653970163758524 decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING .... Finished tests in 0.007873s, 508.0378 tests/s, 635.0472 assertions/s. 4 tests, 5 assertions, 0 failures, 0 errors, 0 skips
Scala
- Output:
Best seen running in your browser either by ScalaFiddle (ES aka JavaScript, non JVM) or Scastie (remote JVM).
<lang Scala>object StraddlingCheckerboard extends App {
private val dictonary = Map("H" -> "0", "O" -> "1", "L" -> "2", "M" -> "4", "E" -> "5", "S" -> "6", "R" -> "8", "T" -> "9", "A" -> "30", "B" -> "31", "C" -> "32", "D" -> "33", "F" -> "34", "G" -> "35", "I" -> "36", "J" -> "37", "K" -> "38", "N" -> "39", "P" -> "70", "Q" -> "71", "U" -> "72", "V" -> "73", "W" -> "74", "X" -> "75", "Y" -> "76", "Z" -> "77", "." -> "78", "/" -> "79", "0" -> "790", "1" -> "791", "2" -> "792", "3" -> "793", "4" -> "794", "5" -> "795", "6" -> "796", "7" -> "797", "8" -> "798", "9" -> "799")
private def encode(s: String) = s.toUpperCase.map { case ch: Char => dictonary.getOrElse(ch.toString, "") }.mkString
private def decode(s: String) = { val revDictionary: Map[String, String] = dictonary.map {case (k, v) => (v, k)}
val pat = "(79.|3.|7.|.)".r pat.findAllIn(s).map { el => revDictionary.getOrElse(el, "")}.addString(new StringBuilder) }
val enc = encode( "One night-it was on the twentieth of March, " + "1888-I was returning" ) println(enc) println(decode(enc))
}</lang>
Tcl
Structured as a class, the instances of which contain encoding and decoding mappings suitable for use with Tcl's built in string remapping engine. This uses the fact that no sequence of digits in the encoded form that maps to one character is a prefix of the sequence for any other character. (Inspired by the description of the Raku solution.) <lang tcl>package require Tcl 8.6
oo::class create StraddlingCheckerboardCypher {
variable encmap decmap constructor table {
# Sanity check the table foreach ch [lindex $table 0] i {"" 0 1 2 3 4 5 6 7 8 9} { if {$ch eq "" && $i ne "" && [lsearch -index 0 $table $i] < 1} { error "bad checkerboard table" } } # Synthesize the escaped number row foreach row $table { if {"/" ni $row} continue set pfx [lindex $row 0][expr {[lsearch -exact $row "/"]-1}] lappend table [list $pfx 0 1 2 3 4 5 6 7 8 9] break } # Build the actual per-character mapping foreach row $table { foreach ch [lrange $row 1 end] n {0 1 2 3 4 5 6 7 8 9} { if {$ch in {"" "/"}} continue; # Skip escape cases lappend encmap $ch [lindex $row 0]$n lappend decmap [lindex $row 0]$n $ch } }
}
# These methods just sanitize their input and apply the map method encode msg {
string map $encmap [regsub -all {[^A-Z0-9.]} [string toupper $msg] ""]
} method decode msg {
string map $decmap [regsub -all {[^0-9]} $msg ""]
}
}</lang> Demonstration code: <lang tcl>StraddlingCheckerboardCypher create demo {
{{} E T {} A O N {} R I S} {2 B C D F G H J K L M} {6 P Q / U V W X Y Z .}
} set input "One night-it was on the twentieth of March, 1888-I was returning" set encrypted [demo encode $input] set output [demo decode $encrypted] puts "Input: $input" puts "Encoded: $encrypted" puts "Decoded: $output"</lang> Output:
Input: One night-it was on the twentieth of March, 1888-I was returning Encoded: 450582425181653945125016505180125423293721256216286286288653970163758524 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
VBScript
<lang vb>' Straddling checkerboard - VBScript - 19/04/2019
Function encrypt(ByVal originalText, ByVal alphabet, blank1, blank2)
Const notEscape = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ." Dim i, j, curChar, escChar, outText Dim cipher 'Hash table Set cipher = CreateObject("Scripting.Dictionary") 'build cipher reference alphabet = UCase(alphabet) : j = 0 For i = 1 To 28 curChar = Mid(alphabet, i, 1) Select Case True Case i>= 1 And i<= 8 If j = blank1 Or j = blank2 Then j = j + 1 'adjust for blank
cipher.Add curChar, CStr(j)
j = j + 1 Case i>= 9 And i<=18
cipher.Add curChar, CStr(blank1) & CStr(i - 9)
Case i>=19 And i<=28
cipher.Add curChar, CStr(blank2) & CStr(i - 19)
End Select 'i If InStr(notEscape, curChar) = 0 Then escChar = curChar 'Wscript.Echo "escChar=" & escChar & " cipher(escChar)=" & cipher(escChar) End If Next 'i For i = 0 To 9: cipher.Add CStr(i), cipher(escChar) & CStr(i): Next 'encrypt each character originalText = UCase(originalText) For i = 1 To Len(originalText) outText = outText & cipher(Mid(originalText, i, 1)) Next encrypt=outText
End Function 'encrypt
Function decrypt(ByVal cipherText, ByVal alphabet, blank1, blank2)
Const notEscape = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ." Dim i, j, curChar, escCipher, outText Dim cipher 'Hash table Set cipher = CreateObject("Scripting.Dictionary") 'build decipher reference alphabet = UCase(alphabet) : j = 0 For i = 1 To 28 curChar = Mid(alphabet, i, 1) Select Case True Case i>= 1 And i<= 8 If j = blank1 Or j = blank2 Then j = j + 1 'adjust for blank
cipher.Add CStr(j),curChar
j = j + 1 Case i>= 9 And i<=18 cipher.Add CStr(blank1) & CStr(i - 9), curChar Case i>=19 And i<=28 cipher.Add CStr(blank2) & CStr(i - 19), curChar End Select 'i If InStr(notEscape, curChar) = 0 Then 'the last element of cipher arrayKeys=cipher.keys escCipher = arrayKeys(cipher.count-1) 'Wscript.Echo "escCipher=" & escCipher & " cipher(escCipher)=" & cipher(escCipher) End If Next 'i For i = 0 To 9: cipher.Add escCipher & CStr(i), CStr(i): Next 'decrypt each character i = 1 Do While i <= Len(cipherText) curChar = Mid(cipherText, i, 1) If curChar = CStr(blank1) Or curChar = CStr(blank2) Then curChar = Mid(cipherText, i, 2) If curChar = escCipher Then curChar = Mid(cipherText, i, 3) End If outText = outText & cipher(curChar) i = i + Len(curChar) Loop 'i decrypt=outText
End Function 'decrypt
message = "One night-it was on the twentieth of March, 1888-I was returning" cipher = "HOLMESRTABCDFGIJKNPQUVWXYZ./" '3 7 <=8 'HOL MES RT 'ABCDFGIJKN 'PQUVWXYZ./ Buffer=Buffer & "Original: " & message & vbCrlf encoded = encrypt(message, cipher, 3, 7) Buffer=Buffer & "encoded: " & encoded & vbCrlf decoded = decrypt(encoded, cipher, 3, 7) Buffer=Buffer & "decoded: " & decoded & vbCrlf Wscript.Echo Buffer </lang>
- Output:
Original: One night-it was on the twentieth of March, 1888-I was returning encoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING
Wren
<lang ecmascript>import "/str" for Str
var board = "ET AON RISBCDFGHJKLMPQ/UVWXYZ." var digits = "0123456789" var rows = " 26" var escape = "62" var key = "0452"
var encrypt = Fn.new { |message|
var msg = Str.upper(message). where { |c| (board.contains(c) || digits.contains(c)) && !" /".contains(c) }.join() var sb = "" for (c in msg) { var idx = board.indexOf(c) if (idx > -1) { var row = (idx/10).floor var col = idx % 10 sb = sb + ((row == 0) ? "%(col)" : "%(rows[row])%(col)") } else { sb = sb + "%(escape)%(c)" } } var enc = sb.bytes.toList var i = 0 for (c in enc) { var k = key[i%4].bytes[0] - 48 if (k != 0) { var j = c - 48 enc[i] = 48 + ((j + k) % 10) } i = i + 1 } return enc.map { |b| String.fromByte(b) }.join()
}
var decrypt = Fn.new { |encoded|
var enc = encoded.bytes.toList var i = 0 for (c in enc) { var k = key[i%4].bytes[0] - 48 if (k != 0) { var j = c - 48 enc[i] = 48 + ((j >= k) ? (j - k) % 10 : (10 + j - k) % 10) } i = i + 1 } var len = enc.count var sb = "" i = 0 while (i < len) { var c = enc[i] var idx = rows.indexOf((c-48).toString) if (idx == -1) { var idx2 = c - 48 sb = sb + board[idx2] i = i + 1 } else if ("%(c-48)%(enc[i + 1]-48)" == escape) { sb = sb + (enc[i + 2] - 48).toString i = i + 3 } else { var idx2 = idx * 10 + enc[i + 1] - 48 sb = sb + board[idx2] i = i + 2 } } return sb
}
var messages = [
"Attack at dawn", "One night-it was on the twentieth of March, 1888-I was returning", "In the winter 1965/we were hungry/just barely alive", "you have put on 7.5 pounds since I saw you.", "The checkerboard cake recipe specifies 3 large eggs and 2.25 cups of flour."
] for (message in messages) {
var encrypted = encrypt.call(message) var decrypted = decrypt.call(encrypted) System.print("\nMessage : %(message)") System.print("Encrypted : %(encrypted)") System.print("Decrypted : %(decrypted)")
}</lang>
- Output:
Message : Attack at dawn Encrypted : 3565257935743007 Decrypted : ATTACKATDAWN Message : One night-it was on the twentieth of March, 1888-I was returning Encrypted : 495786945533698149645468540384645875238925776668221480708005915367278976 Decrypted : ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING Message : In the winter 1965/we were hungry/just barely alive Encrypted : 89645417896270736648201450026959060839767024608116557470618482160 Decrypted : INTHEWINTER1965WEWEREHUNGRYJUSTBARELYALIVE Message : you have put on 7.5 pounds since I saw you. Encrypted : 61983605685800834914704829124087264189730245691940889 Decrypted : YOUHAVEPUTON7.5POUNDSSINCEISAWYOU. Message : The checkerboard cake recipe specifies 3 large eggs and 2.25 cups of flour. Encrypted : 160225770664742408892673362274738052905225343251668487244454469139746678907466041088039436848815704 Decrypted : THECHECKERBOARDCAKERECIPESPECIFIES3LARGEEGGSAND2.25CUPSOFFLOUR.
zkl
<lang zkl>var [const]
val2key=Dictionary( "A","30", "B","31", "C","32", "D","33", "E","5", "F","34", "G","35", "H","0", "I","36", "J","37", "K","38", "L","2", "M","4", ".","78", "N","39", "/","79", "O","1", "0","790", "P","70", "1","791", "Q","71", "2","792", "R","8", "3","793", "S","6", "4","794" ,"T","9", "5","795", "U","72", "6","796", "V","73", "7","797", "W","74", "8","798", "X","75", "9","799", "Y","76", "Z","77"), key2val=val2key.pump(Dictionary(),"reverse");
fcn encode(txt){ txt.toUpper().pump(String,val2key.find.fp1("")) } fcn decode(str){ RegExp("79.|3.|7.|.").pump(str,String,key2val.get) }</lang> <lang zkl>txt:="One night-it was on the twentieth of March, 1888-I was returning"; str:=encode(txt); println("Encoded: ", str); println("Decoded: ", decode(str));</lang>
- Output:
ncoded: 139539363509369743061399059745399365901344308320791798798798367430685972839363935 Decoded: ONENIGHTITWASONTHETWENTIETHOFMARCH1888IWASRETURNING