Bifid cipher
You are encouraged to solve this task according to the task description, using any language you may know.
- Description
The Bifid cipher is a polygraphic substitution cipher which was invented by Félix Delastelle in around 1901. It uses a 5 x 5 Polybius square combined with transposition and fractionation to encrypt a message. Any 5 x 5 Polybius square can be used but, as it only has 25 cells and there are 26 letters of the (English) alphabet, one cell needs to represent two letters - I and J being a common choice.
- Operation
Suppose we want to encrypt the message "ATTACKATDAWN".
We use this archetypal Polybius square where I and J share the same position.
x/y 1 2 3 4 5 ------------- 1 | A B C D E 2 | F G H I K 3 | L M N O P 4 | Q R S T U 5 | V W X Y Z
The message is first converted to its x, y coordinates, but they are written vertically beneath.
A T T A C K A T D A W N 1 4 4 1 1 2 1 4 1 1 5 3 1 4 4 1 3 5 1 4 4 1 2 3
They are then arranged in a row.
1 4 4 1 1 2 1 4 1 1 5 3 1 4 4 1 3 5 1 4 4 1 2 3
Finally, they are divided up into pairs which are used to look up the encrypted letters in the square.
14 41 12 14 11 53 14 41 35 14 41 23 D Q B D A X D Q P D Q H
The encrypted message is therefore "DQBDAXDQPDQH".
Decryption can be achieved by simply reversing these steps.
- Task
Write routines in your language to encrypt and descrypt a message using the Bifid cipher.
Use them to verify (including subsequent decryption):
1. The above example.
2. The example in the Wikipedia article using the message and Polybius square therein.
3. The above example but using the Polybius square in the Wikipedia article to illustrate that it doesn't matter which square you use as long, of course, as the same one is used for both encryption and decryption.
In addition, encrypt and decrypt the message "The invasion will start on the first of January" using any Polybius square you like. Convert the message to upper case and ignore spaces.
- Bonus
Suggest a way in which the cipher could be modified so that ALL 26 letters can be uniquely encrypted.
- Related task
AArch64 Assembly
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program bifid64.s */
/*******************************************/
/* Constantes */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ MESSSIZE, 2000
.equ BUFFERSIZE, 2000
/*******************************************/
/* Macros */
/*******************************************/
//.include "../../ficmacros64.inc" // for developer debugging
/*******************************************/
/* Initialized data */
/*******************************************/
.data
szMessDebutPgm: .asciz "Program 64 bits start. \n"
szCarriageReturn: .asciz "\n"
szMessFinOK: .asciz "Program normal end. \n"
szMessError: .asciz "\nError Buffer too small!!!\n"
szMessString: .asciz "String :\n"
szMessEncrip: .asciz "\nEncrypted :\n"
szMessDecrip: .asciz "\nDecrypted :\n"
//szString1: .asciz "ABCDEFGHIJKLMNOPQRSTUVWXYZ!.?abcdefghijklmnopqrstuvwxyz"
//szString1: .asciz "attackatdawn"
szString1: .asciz "ATTACKATDAWN"
//szString1: .asciz "ABCD"
szString2: .asciz "FLEEATONCE"
szString3: .asciz "The invasion will start on the first of January"
szPolybe1: .ascii "ABCDE"
.ascii "FGHIK"
.ascii "LMNOP"
.ascii "QRSTU"
.asciz "VWXYZ"
szPolybe2: .ascii "BGWKZ"
.ascii "QPNDS"
.ascii "IOAXE"
.ascii "FCLUM"
.asciz "THYVR"
/*******************************************/
/* UnInitialized data */
/*******************************************/
.bss
.align 4
tabiposX: .skip 8 * MESSSIZE
tabiposY: .skip 8 * MESSSIZE
sBuffex1: .skip BUFFERSIZE
sBuffex2: .skip BUFFERSIZE
/*******************************************/
/* code section */
/*******************************************/
.text
.global main
main:
ldr x0,qAdrszMessDebutPgm
bl affichageMess
ldr x0,qAdrszMessString // display message
bl affichageMess
ldr x0,qAdrszString1 // display string
bl affichageMess
ldr x0,qAdrszString1 // string address
ldr x1,qAdrszPolybe1 // Polybe key
ldr x2,qAdrsBuffex1 // encrypted buffer result
bl encrypt
cmp x0,#0
ble 99f
ldr x0,qAdrszMessEncrip
bl affichageMess
ldr x0,qAdrsBuffex1 // display encrypted buffer
bl affichageMess
ldr x0,qAdrsBuffex1 // encrypted buffer
ldr x1,qAdrszPolybe1 // Polybe key
ldr x2,qAdrsBuffex2 // decrypted buffer
bl decrypt
ldr x0,qAdrszMessDecrip
bl affichageMess
ldr x0,qAdrsBuffex2 // display decrypted buffer
bl affichageMess
ldr x0,qAdrszCarriageReturn
bl affichageMess
ldr x0,qAdrszMessString // display message
bl affichageMess
ldr x0,qAdrszString2 // display string
bl affichageMess
ldr x0,qAdrszString2 // string address
ldr x1,qAdrszPolybe2 // Polybe key
ldr x2,qAdrsBuffex1 // encrypted buffer result
bl encrypt
cmp x0,#0
ble 99f
ldr x0,qAdrszMessEncrip
bl affichageMess
ldr x0,qAdrsBuffex1 // display encrypted buffer
bl affichageMess
ldr x0,qAdrsBuffex1 // encrypted buffer
ldr x1,qAdrszPolybe2 // Polybe key
ldr x2,qAdrsBuffex2 // decrypted buffer
bl decrypt
ldr x0,qAdrszMessDecrip
bl affichageMess
ldr x0,qAdrsBuffex2 // display decrypted buffer
bl affichageMess
ldr x0,qAdrszCarriageReturn
bl affichageMess
ldr x0,qAdrszMessString // display message
bl affichageMess
ldr x0,qAdrszString1 // display string
bl affichageMess
ldr x0,qAdrszString1 // string address
ldr x1,qAdrszPolybe2 // Polybe key
ldr x2,qAdrsBuffex1 // encrypted buffer result
bl encrypt
cmp x0,#0
ble 99f
ldr x0,qAdrszMessEncrip
bl affichageMess
ldr x0,qAdrsBuffex1 // display encrypted buffer
bl affichageMess
ldr x0,qAdrsBuffex1 // encrypted buffer
ldr x1,qAdrszPolybe2 // Polybe key
ldr x2,qAdrsBuffex2 // decrypted buffer
bl decrypt
ldr x0,qAdrszMessDecrip
bl affichageMess
ldr x0,qAdrsBuffex2 // display decrypted buffer
bl affichageMess
ldr x0,qAdrszCarriageReturn
bl affichageMess
ldr x0,qAdrszMessString // display message
bl affichageMess
ldr x0,qAdrszString3 // display string
bl affichageMess
ldr x0,qAdrszString3 // string address
ldr x1,qAdrszPolybe1 // Polybe key
ldr x2,qAdrsBuffex1 // encrypted buffer result
bl encrypt
cmp x0,#0
ble 99f
ldr x0,qAdrszMessEncrip
bl affichageMess
ldr x0,qAdrsBuffex1 // display encrypted buffer
bl affichageMess
ldr x0,qAdrsBuffex1 // encrypted buffer
ldr x1,qAdrszPolybe1 // Polybe key
ldr x2,qAdrsBuffex2 // decrypted buffer
bl decrypt
ldr x0,qAdrszMessDecrip
bl affichageMess
ldr x0,qAdrsBuffex2 // display decrypted buffer
bl affichageMess
ldr x0,qAdrszCarriageReturn
bl affichageMess
ldr x0,qAdrszMessFinOK
bl affichageMess
b 100f
99:
ldr x0,qAdrszMessError // error
bl affichageMess
mov x0, #1
100: // standard end of the program
mov x0, #0 // return code
mov x8,EXIT
svc 0 // perform system call
qAdrszMessString: .quad szMessString
qAdrszMessDecrip: .quad szMessDecrip
qAdrszMessEncrip: .quad szMessEncrip
qAdrszString1: .quad szString1
qAdrszPolybe1: .quad szPolybe1
qAdrszString2: .quad szString2
qAdrszString3: .quad szString3
qAdrszPolybe2: .quad szPolybe2
qAdrsBuffex1: .quad sBuffex1
qAdrsBuffex2: .quad sBuffex2
qAdrszMessDebutPgm: .quad szMessDebutPgm
qAdrszMessFinOK: .quad szMessFinOK
qAdrszCarriageReturn: .quad szCarriageReturn
qAdrszMessError: .quad szMessError
/******************************************************************/
/* encrypt strings */
/******************************************************************/
/* r0 contains the address of the string1 */
/* r1 contains Polybe area address
/* r2 contains the address of the encrypted string */
/* r0 return buffer lenght */
encrypt:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! //
stp x4,x5,[sp,-16]! //
stp x6,x7,[sp,-16]! //
stp x8,x9,[sp,-16]! //
stp x10,x11,[sp,-16]! //
mov x3,#0 // counter byte string 1
mov x5,#0 // counter byte buffer
1:
ldrb w7,[x0,x3] // load byte string 1
cmp x7,#0 // zero final ?
beq 4f
cmp x7,#65 // < A ?
cinc x3,x3,lt
blt 1b
cmp x7,#90 // > Z
ble 2f
cmp x7,#97 // < a ?
cinc x3,x3,lt
blt 1b
cmp x7,#122 //> z
cinc x3,x3,gt
bgt 1b
sub x7,x7,#32 // convert minuscul to majuscule
2:
mov x11,'I'
cmp x7,#'J' // change J to I
csel x7,x11,x7,eq
ldr x11,qAdrtabiposX
ldr x12,qAdrtabiposY
mov x6,#0
mov x9,#5
3: // loop to search char in polybe square
ldrb w8,[x1,x6] // load byte polybe
cmp x8,x7 // equal ?
cinc x6,x6,ne
bne 3b
udiv x10,x6,x9 // compute coordonnés
msub x8,x10,x9,x6
strb w10,[x11,x5] // save X position
strb w8,[x12,x5] // save Y position
add x5,x5,#1 // increment indice
add x3,x3,#1
b 1b // and loop
4:
mov x6,#0
mov x8,x5
mov x5,#0
mov x3,#5
5: // convert position line 1 in char
ldrb w9,[x11,x6]
add x6,x6,#1
cmp x6,x8 // first line end ?
csel x6,xzr,x6,ge
bge 7f // jmp for second line
ldrb w7,[x11,x6] // compute rank with position X and Y
mul x9,x3,x9
add x9,x9,x7
ldrb w9,[x1,x9] // load polybe char
strb w9,[x2,x5]
add x5,x5,#1
add x6,x6,#1
cmp x6,x8
blt 5b
mov x6,#0
6: // convert position line 2 in char
ldrb w9,[x12,x6]
add x6,x6,#1
7:
ldrb w7,[x12,x6] // compute rank with position X and Y
mul x9,x3,x9
add x9,x9,x7
ldrb w9,[x1,x9] // load polybe char
strb w9,[x2,x5]
add x5,x5,#1
add x6,x6,#1
cmp x6,x8
blt 6b
mov x9,#0 // zero final
strb w9,[x2,x5]
mov x0,x5
100:
ldp x10,x11,[sp],16 // restau registers
ldp x8,x9,[sp],16 //
ldp x6,x7,[sp],16 //
ldp x4,x5,[sp],16 //
ldp x2,x3,[sp],16 //
ldp x1,lr,[sp],16 //
ret
qAdrtabiposX: .quad tabiposX
qAdrtabiposY: .quad tabiposY
/******************************************************************/
/* decrypt strings */
/******************************************************************/
/* r0 contains the address of the encrypted string1 */
/* r1 contains Polybe area address
/* r2 contains the address of the decrypted string */
/* r0 return buffer lenght */
decrypt:
stp x1,lr,[sp,-16]! // save registers
stp x2,x3,[sp,-16]! //
stp x4,x5,[sp,-16]! //
stp x6,x7,[sp,-16]! //
stp x8,x9,[sp,-16]! //
stp x10,x11,[sp,-16]! //
mov x3,#0 // counter byte string 1
mov x5,#0 // counter byte result buffer
1:
ldrb w7,[x0,x3] // load byte string 1
cmp x7,#0 // zero final ?
csel x0,x5,x0,eq
beq 4f
cmp x7,#65 // < A ?
cinc x3,x3,lt
blt 1b
cmp x7,#90 // > Z
ble 2f
cmp x7,#97 // < a ?
cinc x3,x3,lt
blt 1b
cmp x7,#122 //> z
cinc x3,x3,gt
bgt 1b
sub x7,x7,#32 // convert minuscul to majuscule
2:
ldr x11,qAdrtabiposX
mov x6,#0
mov x9,#5
3: // loop to search char in polybe square
ldrb w8,[x1,x6] // load byte polybe
cmp x8,x7
cinc x6,x6,ne
bne 3b
udiv x10,x6,x9
msub x8,x10,x9,x6
strb w10,[x11,x5]
add x5,x5,#1
strb w8,[x11,x5]
add x5,x5,#1
add x3,x3,#1
b 1b
4:
mov x6,#0 // start indice first line
lsr x8,x5,#1
mov x10,x8 // start indice second line
mov x5,#0
mov x3,#5
5:
ldrb w9,[x11,x6] // load position
ldrb w7,[x11,x10]
mul x9,x3,x9 // compute rank
add x9,x9,x7
ldrb w9,[x1,x9] // load polybe byte
strb w9,[x2,x5] // and store to result
add x5,x5,#1
add x10,x10,#1
add x6,x6,#1
cmp x6,x8 // end ?
blt 5b
mov x9,#0 // 0 final
strb w9,[x2,x5]
mov x0,x5
100:
ldp x10,x11,[sp],16 // restaur registers
ldp x8,x9,[sp],16 //
ldp x6,x7,[sp],16 //
ldp x4,x5,[sp],16 //
ldp x2,x3,[sp],16 //
ldp x1,lr,[sp],16 //
ret
/***************************************************/
/* ROUTINES INCLUDE */
/***************************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeARM64.inc"- Output:
Program 64 bits start. String : ATTACKATDAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN String : FLEEATONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE String : ATTACKATDAWN Encrypted : EYFENGIWDILA Decrypted : ATTACKATDAWN String : The invasion will start on the first of January Encrypted : RBPDHPHOQTNRBITMFODYPSAOSIAOBTOPDHTDCVI Decrypted : THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY Program normal end.
Ada
-- Bifid cipher
-- J. Carter 2023 May
-- The Bifid cipher is included as part of the PragmAda Reusable Components (https://github.com/jrcarter/PragmARC)
with Ada.Text_IO;
with PragmARC.Encryption.Bifid;
procedure Bifid_Test is
package Bifid renames PragmARC.Encryption.Bifid;
Key_1 : constant Bifid.Square_Layout := ("ABCDE", "FGHIK", "LMNOP", "QRSTU", "VWXYZ");
Key_2 : constant Bifid.Square_Layout := ("BGWKZ", "QPNDS", "IOAXE", "FCLUM", "THYVR");
Msg_1 : constant String := "ATTACKATDAWN";
Msg_2 : constant String := "FLEEATONCE";
Msg_3 : constant String := "THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY";
Crypt_1 : String (Msg_1'Range);
Crypt_2 : String (Msg_2'Range);
Crypt_3 : String (Msg_3'Range);
begin -- Bifid_Test
Crypt_1 := Bifid.Encrypt (Msg_1, Key_1);
Ada.Text_IO.Put_Line (Item => Msg_1 & " => " & Crypt_1 & " => " & Bifid.Decrypt (Crypt_1, Key_1) );
Crypt_2 := Bifid.Encrypt (Msg_2, Key_2);
Ada.Text_IO.Put_Line (Item => Msg_2 & " => " & Crypt_2 & " => " & Bifid.Decrypt (Crypt_2, Key_2) );
Crypt_1 := Bifid.Encrypt (Msg_1, Key_2);
Ada.Text_IO.Put_Line (Item => Msg_1 & " => " & Crypt_1 & " => " & Bifid.Decrypt (Crypt_1, Key_2) );
Crypt_3 := Bifid.Encrypt (Msg_3, Key_2);
Ada.Text_IO.Put_Line (Item => Msg_3 & " => " & Crypt_3 & " => " & Bifid.Decrypt (Crypt_3, Key_2) );
end Bifid_Test;
- Output:
ATTACKATDAWN => DQBDAXDQPDQH => ATTACKATDAWN FLEEATONCE => UAEOLWRINS => FLEEATONCE ATTACKATDAWN => EYFENGIWDILA => ATTACKATDAWN THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY => RASOAQXCYRORXESXADETSWLTNIATEGISBRGBALY => THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
ALGOL 68
Using additional test cases and 5x5 squares from the EasyLang and other samples, plus using 6x6 and 8x8 squares for the bonus.
BEGIN # Bifid cipher #
# mode to hold the details of a Bifid cipher #
MODE BIFID = STRUCT( STRING key # the Polybius square, linearised #
, STRING pre from # pre-translation, "from" string #
, STRING pre to # pre-tramslatiion "to" string #
);
# string utilities #
# returns the length of s #
OP LENGTH = ( STRING s )INT: ( UPB s - LWB s ) + 1;
# returns the index of c in s, or LWB s - 1 if it is not present #
PRIO INDEXOF = 1;
OP INDEXOF = ( STRING s, CHAR c )INT:
BEGIN
INT index := LWB s - 1;
VOID( char in string( c, index, s ) ); # discard the result #
index
END # INDEXOF # ;
# returns text with the characters in from chars replaced with the #
# corresponding characters in to chars #
PROC translate = ( STRING text, from chars, to chars )STRING:
IF LWB from chars /= LWB to chars OR UPB from chars /= UPB to chars
THEN """from"" and ""to"" have different bounds (translate)"
ELIF from chars = ""
THEN text
ELSE # the from and to strings have the same bounds #
STRING result := text;
FOR r pos FROM LWB result TO UPB result DO
INT t pos = from chars INDEXOF result[ r pos ];
IF t pos >= LWB from chars THEN result[ r pos ] := to chars[ t pos ] FI
OD;
result
FI # translate # ;
# end string utilities #
# returns text encrypted according to cipher #
PRIO ENCRYPT = 9;
OP ENCRYPT = ( STRING text, BIFID cipher )STRING:
IF STRING key = ( key OF cipher )[ AT 1 ];
INT key length = LENGTH key;
INT sq width = ENTIER sqrt( key length );
sq width * sq width /= key length
THEN "**** Bifid key is not a square"
ELSE # the key is a square #
STRING msg1 = translate( text, pre from OF cipher, pre to OF cipher )[ AT 1 ];
STRING msg := "";
FOR m pos FROM LWB msg1 TO UPB msg1 DO
IF msg1[ m pos ] /= " " THEN msg +:= msg1[ m pos ] FI
OD;
INT m max = LENGTH msg;
[ 1 : 2 * m max ]INT coordinates;
FOR m pos TO m max DO
INT c index := key INDEXOF msg[ m pos ];
IF c index >= LWB key THEN c index -:= 1 FI;
coordinates[ m pos ] := c index OVER sq width;
coordinates[ m pos + m max ] := c index MOD sq width
OD;
STRING result := "";
FOR c pos BY 2 TO UPB coordinates DO
result +:= key[ ( coordinates[ c pos ] * sq width )
+ coordinates[ c pos + 1 ]
+ 1
]
OD;
result
FI # ENCRYPT # ;
# returns text decrypted according to cipher #
PRIO DECRYPT = 9;
OP DECRYPT = ( STRING text, BIFID cipher )STRING:
IF STRING key = ( key OF cipher )[ AT 1 ];
INT key length = LENGTH key;
INT sq width = ENTIER sqrt( key length );
sq width * sq width /= key length
THEN "**** Bifid key is not a square"
ELSE # the key is a square #
STRING msg = text[ AT 1 ];
INT m max = LENGTH msg;
[ 1 : 2 * m max ]INT coordinates;
INT c pos := 0;
FOR m pos TO m max DO
INT c index := key INDEXOF msg[ m pos ];
IF c index >= LWB key THEN c index -:= 1 FI;
coordinates[ c pos +:= 1 ] := c index OVER sq width;
coordinates[ c pos +:= 1 ] := c index MOD sq width
OD;
STRING result := "";
FOR i TO m max DO
result +:= key[ ( coordinates[ i ] * sq width )
+ coordinates[ i + m max ]
+ 1
]
OD;
result
FI # DECRYPT # ;
# tests the ENCRYPT and DECRYPT operators #
PROC test bifid = ( BIFID cipher, STRING text )VOID:
BEGIN
STRING code = text ENCRYPT cipher;
print( ( text, " -> ", code, newline ) );
print( ( code, " -> ", code DECRYPT cipher, newline ) )
END # text bifid # ;
# Bifid ciphers for tests #
BIFID bifid 5 abc = ( "ABCDEFGHIKLMNOPQRSTUVWXYZ"
, "Jabcdefghijklmnopqrstuvwxyz"
, "IABCDEFGHIIKLMNOPQRSTUVWXYZ"
);
BIFID bifid 5 bgw = ( "BGWKZQPNDSIOAXEFCLUMTHYVR"
, "Jabcdefghijklmnopqrstuvwxyz"
, "IABCDEFGHIIKLMNOPQRSTUVWXYZ"
);
BIFID bifid 6 abc = ( "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
, "abcdefghijklmnopqrstuvwxyz"
, "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
);
BIFID bifid 8 abc = ( "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789\/"
, " "
, "/"
);
# basic task - using 5x5 Polybius squares #
test bifid( bifid 5 abc, "ATTACKATDAWN" );
print( ( newline ) );
test bifid( bifid 5 bgw, "FLEEATONCE" );
test bifid( bifid 5 bgw, "ATTACKATDAWN" );
test bifid( bifid 5 bgw, "The invasion will begin on the first of January" );
print( ( newline ) );
# bonus - using a 6x6 square #
test bifid( bifid 6 abc, "The invasion will begin on the first of January" );
print( ( newline ) );
# bonus - using an 8x8 square #
test bifid( bifid 8 abc, "The invasion will begin on the first of January" )
END- Output:
ATTACKATDAWN -> DQBDAXDQPDQH DQBDAXDQPDQH -> ATTACKATDAWN FLEEATONCE -> UAEOLWRINS UAEOLWRINS -> FLEEATONCE ATTACKATDAWN -> EYFENGIWDILA EYFENGIWDILA -> ATTACKATDAWN The invasion will begin on the first of January -> RASOAQXFIOORXESXADETSWLTNIAZQOISBRGBALY RASOAQXFIOORXESXADETSWLTNIAZQOISBRGBALY -> THEINVASIONWILLBEGINONTHEFIRSTOFIANUARY The invasion will begin on the first of January -> TBPDIPHGBIOTAIVMGPCZKNSCN09KCIHK64I7BM4 TBPDIPHGBIOTAIVMGPCZKNSCN09KCIHK64I7BM4 -> THEINVASIONWILLBEGINONTHEFIRSTOFJANUARY The invasion will begin on the first of January -> Ufkrss\knbkns9j7lt9fLldzO6/UQ/Ct7wX4/p36cvH5Xya Ufkrss\knbkns9j7lt9fLldzO6/UQ/Ct7wX4/p36cvH5Xya -> The/invasion/will/begin/on/the/first/of/January
AppleScript
(* The "square" here is only notional, the characters' coordinates being calculated
from their offsets in a linear text key. But a square key is accepted if the
signaller's careless enough to keep or transmit one in this form. *)
on bifidEncipher(message, square)
return transcipher(message, square, 1)
end bifidEncipher
on bifidDecipher(message, square)
return transcipher(message, square, 2)
end bifidDecipher
on transcipher(message, square, code) -- code: 1 = encipher, 2 = decipher.
-- Check and massage the input.
set message to join(message's words, "")
if (message contains ".") then set message to replaceText(".", "", message)
set square to join(join(square, "")'s words, "")
set squarea to (count square)
set sqrt to (squarea ^ 0.5) as integer
if (sqrt * sqrt ≠ squarea) then error "Invalid key."
ignoring case
if ((sqrt < 6) and (message contains "J")) then ¬
set message to replaceText("J", "I", message)
end ignoring
-- Calculate coordinates from the message characters' offsets in the "square" text
-- and either split and recombine them (when enciphering) or not (deciphering).
set list1 to {}
set list2 to {{}, list1}'s item code
set astid to AppleScript's text item delimiters
ignoring case and diacriticals
repeat with chr in message
set AppleScript's text item delimiters to chr
set |offset - 1| to (count square's first text item)
set list1's end to |offset - 1| div sqrt + 1
set list2's end to |offset - 1| mod sqrt + 1
end repeat
end ignoring
set AppleScript's text item delimiters to astid
set coords to {list1 & list2, list1}'s item code
-- Calculate new offsets from the appropriate numbers in the coords list
-- and get the characters offset by those amounts in the "square" text.
set chrs to {}
set nCoords to (count coords)
set indexDifference to {1, nCoords div 2}'s item code
repeat with i from 1 to (nCoords div code) by (3 - code)
set |offset| to ((coords's item i) - 1) * sqrt + (coords's item (i + indexDifference))
set chrs's end to square's character |offset|
end repeat
return join(chrs, "")
end transcipher
on join(lst, delim)
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to delim
set txt to lst as text
set AppleScript's text item delimiters to astid
return txt
end join
on replaceText(searchText, replacement, mainText)
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to searchText
set textItems to mainText's text items
set AppleScript's text item delimiters to replacement
set mainText to textItems as text
set AppleScript's text item delimiters to astid
return mainText
end replaceText
on task()
set output to {}
repeat with this in {{"Given example:", "ATTACKATDAWN", "ABCDEFGHIKLMNOPQRSTUVWXYZ"}, ¬
{"Wikipedia example:", "FLEEATONCE", {"BGWKZ", "QPNDS", "IOAXE", "FCLUM", "THYVR"}}, ¬
{"A 6 x 6 square allows all 36 letters & digits to be encoded:", ¬
"The invasion will start on the 1st of January", ¬
"THEQUI
9CKBR0
1OWNF8
7XJMP2
3SVLA6
5ZYDG4"}}
set {heading, message, square} to this
set encrypted to bifidEncipher(message, square)
set decrypted to bifidDecipher(encrypted, square)
set output's end to heading
set output's end to message & " --> " & encrypted & " --> " & decrypted
end repeat
return join(output, linefeed)
end task
task()
- Output:
"Given example:
ATTACKATDAWN --> DQBDAXDQPDQH --> ATTACKATDAWN
Wikipedia example:
FLEEATONCE --> UAEOLWRINS --> FLEEATONCE
A 6 x 6 square allows all 36 letters & digits to be encoded:
The invasion will start on the 1st of January --> TTFAEWUAU9WTE3WP1S5KDF0B8M9AH7KHHVLAV --> THEINVASIONWILLSTARTONTHE1STOFJANUARY"
ARM Assembly
/* ARM assembly Raspberry PI */
/* program bifid.s */
/* REMARK 1 : this program use routines in a include file
see task Include a file language arm assembly
for the routine affichageMess conversion10
see at end of this program the instruction include */
/*******************************************/
/* Constantes */
/*******************************************/
.include "../constantes.inc"
.equ MESSSIZE, 2000
.equ BUFFERSIZE, 2000
/*******************************************/
/* Macros */
/*******************************************/
//.include "../../ficmacros32.inc" @ for developer debugging
/*******************************************/
/* Initialized data */
/*******************************************/
.data
szMessDebutPgm: .asciz "Program 32 bits start. \n"
szCarriageReturn: .asciz "\n"
szMessFinOK: .asciz "Program normal end. \n"
szMessError: .asciz "\nError Buffer too small!!!\n"
szMessString: .asciz "String :\n"
szMessEncrip: .asciz "\nEncrypted :\n"
szMessDecrip: .asciz "\nDecrypted :\n"
//szString1: .asciz "ABCDEFGHIJKLMNOPQRSTUVWXYZ!.?abcdefghijklmnopqrstuvwxyz"
//szString1: .asciz "attackatdawn"
szString1: .asciz "ATTACKATDAWN"
//szString1: .asciz "ABCD"
szString2: .asciz "FLEEATONCE"
szString3: .asciz "L'invasion commencera le premier janvier"
szPolybe1: .ascii "ABCDE"
.ascii "FGHIK"
.ascii "LMNOP"
.ascii "QRSTU"
.asciz "VWXYZ"
szPolybe2: .ascii "BGWKZ"
.ascii "QPNDS"
.ascii "IOAXE"
.ascii "FCLUM"
.asciz "THYVR"
/*******************************************/
/* UnInitialized data */
/*******************************************/
.bss
.align 4
tabiposX: .skip 4 * MESSSIZE
tabiposY: .skip 4 * MESSSIZE
sBuffer1: .skip BUFFERSIZE
sBuffer2: .skip BUFFERSIZE
/*******************************************/
/* code section */
/*******************************************/
.text
.global main
main:
ldr r0,iAdrszMessDebutPgm
bl affichageMess
ldr r0,iAdrszMessString @ display message
bl affichageMess
ldr r0,iAdrszString1 @ display string
bl affichageMess
ldr r0,iAdrszString1 @ string address
ldr r1,iAdrszPolybe1 @ Polybe key
ldr r2,iAdrsBuffer1 @ encrypted buffer result
bl encrypt
cmp r0,#0
ble 99f
ldr r0,iAdrszMessEncrip
bl affichageMess
ldr r0,iAdrsBuffer1 @ display encrypted buffer
bl affichageMess
ldr r0,iAdrsBuffer1 @ encrypted buffer
ldr r1,iAdrszPolybe1 @ Polybe key
ldr r2,iAdrsBuffer2 @ decrypted buffer
bl decrypt
ldr r0,iAdrszMessDecrip
bl affichageMess
ldr r0,iAdrsBuffer2 @ display decrypted buffer
bl affichageMess
ldr r0,iAdrszCarriageReturn
bl affichageMess
ldr r0,iAdrszMessString @ display message
bl affichageMess
ldr r0,iAdrszString2 @ display string
bl affichageMess
ldr r0,iAdrszString2 @ string address
ldr r1,iAdrszPolybe2 @ Polybe key
ldr r2,iAdrsBuffer1 @ encrypted buffer result
bl encrypt
cmp r0,#0
ble 99f
ldr r0,iAdrszMessEncrip
bl affichageMess
ldr r0,iAdrsBuffer1 @ display encrypted buffer
bl affichageMess
ldr r0,iAdrsBuffer1 @ encrypted buffer
ldr r1,iAdrszPolybe2 @ Polybe key
ldr r2,iAdrsBuffer2 @ decrypted buffer
bl decrypt
ldr r0,iAdrszMessDecrip
bl affichageMess
ldr r0,iAdrsBuffer2 @ display decrypted buffer
bl affichageMess
ldr r0,iAdrszCarriageReturn
bl affichageMess
ldr r0,iAdrszMessString @ display message
bl affichageMess
ldr r0,iAdrszString1 @ display string
bl affichageMess
ldr r0,iAdrszString1 @ string address
ldr r1,iAdrszPolybe2 @ Polybe key
ldr r2,iAdrsBuffer1 @ encrypted buffer result
bl encrypt
cmp r0,#0
ble 99f
ldr r0,iAdrszMessEncrip
bl affichageMess
ldr r0,iAdrsBuffer1 @ display encrypted buffer
bl affichageMess
ldr r0,iAdrsBuffer1 @ encrypted buffer
ldr r1,iAdrszPolybe2 @ Polybe key
ldr r2,iAdrsBuffer2 @ decrypted buffer
bl decrypt
ldr r0,iAdrszMessDecrip
bl affichageMess
ldr r0,iAdrsBuffer2 @ display decrypted buffer
bl affichageMess
ldr r0,iAdrszCarriageReturn
bl affichageMess
ldr r0,iAdrszMessString @ display message
bl affichageMess
ldr r0,iAdrszString3 @ display string
bl affichageMess
ldr r0,iAdrszString3 @ string address
ldr r1,iAdrszPolybe1 @ Polybe key
ldr r2,iAdrsBuffer1 @ encrypted buffer result
bl encrypt
cmp r0,#0
ble 99f
ldr r0,iAdrszMessEncrip
bl affichageMess
ldr r0,iAdrsBuffer1 @ display encrypted buffer
bl affichageMess
ldr r0,iAdrsBuffer1 @ encrypted buffer
ldr r1,iAdrszPolybe1 @ Polybe key
ldr r2,iAdrsBuffer2 @ decrypted buffer
bl decrypt
ldr r0,iAdrszMessDecrip
bl affichageMess
ldr r0,iAdrsBuffer2 @ display decrypted buffer
bl affichageMess
ldr r0,iAdrszCarriageReturn
bl affichageMess
ldr r0,iAdrszMessFinOK
bl affichageMess
b 100f
99:
ldr r0,iAdrszMessError @ error
bl affichageMess
mov r0, #1
100: @ standard end of the program
mov r0, #0 @ return code
mov r7, #EXIT @ request to exit program
svc 0 @ perform system call
iAdrszMessString: .int szMessString
iAdrszMessDecrip: .int szMessDecrip
iAdrszMessEncrip: .int szMessEncrip
iAdrszString1: .int szString1
iAdrszPolybe1: .int szPolybe1
iAdrszString2: .int szString2
iAdrszString3: .int szString3
iAdrszPolybe2: .int szPolybe2
iAdrsBuffer1: .int sBuffer1
iAdrsBuffer2: .int sBuffer2
iAdrszMessDebutPgm: .int szMessDebutPgm
iAdrszMessFinOK: .int szMessFinOK
iAdrszCarriageReturn: .int szCarriageReturn
iAdrszMessError: .int szMessError
/******************************************************************/
/* encrypt strings */
/******************************************************************/
/* r0 contains the address of the string1 */
/* r1 contains Polybe area address
/* r2 contains the address of the encrypted string */
/* r0 return buffer lenght */
encrypt:
push {r3-r12,lr} @ save registers
mov r3,#0 @ counter byte string 1
mov r5,#0 @ counter byte buffer
1:
ldrb r7,[r0,r3] @ load byte string 1
cmp r7,#0 @ zero final ?
beq 4f
cmp r7,#65 @ < A ?
addlt r3,#1
blt 1b
cmp r7,#90 @ > Z
ble 2f
cmp r7,#97 @ < a ?
addlt r3,#1
blt 1b
cmp r7,#122 @> z
addgt r3,#1
bgt 1b
sub r7,#32 @ convert minuscul to majuscule
2:
cmp r7,#'J' @ change J to I
moveq r7,#'I'
ldr r11,iAdrtabiposX
ldr r12,iAdrtabiposY
mov r6,#0
mov r9,#5
3: @ loop to search char in polybe square
ldrb r8,[r1,r6] @ load byte polybe
cmp r8,r7 @ equal ?
addne r6,#1
bne 3b
udiv r10,r6,r9 @ compute coordonnés
mls r8,r10,r9,r6
strb r10,[r11,r5] @ save X position
strb r8,[r12,r5] @ save Y position
add r5,r5,#1 @ increment indice
add r3,r3,#1
b 1b @ and loop
4:
mov r6,#0
mov r8,r5
mov r5,#0
mov r3,#5
5: @ convert position line 1 in char
ldrb r9,[r11,r6]
add r6,r6,#1
cmp r6,r8 @ first line end ?
movge r6,#0
bge 7f @ jmp for second line
ldrb r7,[r11,r6] @ compute rank with position X and Y
mul r9,r3,r9
add r9,r9,r7
ldrb r9,[r1,r9] @ load polybe char
strb r9,[r2,r5]
add r5,r5,#1
add r6,r6,#1
cmp r6,r8
blt 5b
mov r6,#0
6: @ convert position line 2 in char
ldrb r9,[r12,r6]
add r6,r6,#1
7:
ldrb r7,[r12,r6] @ compute rank with position X and Y
mul r9,r3,r9
add r9,r9,r7
ldrb r9,[r1,r9] @ load polybe char
strb r9,[r2,r5]
add r5,r5,#1
add r6,r6,#1
cmp r6,r8
blt 6b
mov r9,#0 @ zero final
strb r9,[r2,r5]
mov r0,r5
100:
pop {r3-r12,pc} @ restaur registers
iAdrtabiposX: .int tabiposX
iAdrtabiposY: .int tabiposY
/******************************************************************/
/* decrypt strings */
/******************************************************************/
/* r0 contains the address of the encrypted string1 */
/* r1 contains Polybe area address
/* r2 contains the address of the decrypted string */
/* r0 return buffer lenght */
decrypt:
push {r3-r11,lr} @ save registers
mov r3,#0 @ counter byte string 1
mov r5,#0 @ counter byte result buffer
1:
ldrb r7,[r0,r3] @ load byte string 1
cmp r7,#0 @ zero final ?
moveq r0,r5
beq 4f
cmp r7,#65 @ < A ?
addlt r3,#1
blt 1b
cmp r7,#90 @ > Z
ble 2f
cmp r7,#97 @ < a ?
addlt r3,#1
blt 1b
cmp r7,#122 @> z
addgt r3,#1
bgt 1b
sub r7,#32 @ convert minuscul to majuscule
2:
ldr r11,iAdrtabiposX
mov r6,#0
mov r9,#5
3: @ loop to search char in polybe square
ldrb r8,[r1,r6] @ load byte polybe
cmp r8,r7
addne r6,#1
bne 3b
udiv r10,r6,r9
mls r8,r10,r9,r6
strb r10,[r11,r5]
add r5,r5,#1
strb r8,[r11,r5]
add r5,r5,#1
add r3,#1
b 1b
4:
mov r6,#0 @ start indice first line
lsr r8,r5,#1
mov r10,r8 @ start indice second line
mov r5,#0
mov r3,#5
5:
ldrb r9,[r11,r6] @ load position
ldrb r7,[r11,r10]
mul r9,r3,r9 @ compute rank
add r9,r9,r7
ldrb r9,[r1,r9] @ load polybe byte
strb r9,[r2,r5] @ and store to result
add r5,r5,#1
add r10,r10,#1
add r6,r6,#1
cmp r6,r8 @ end ?
blt 5b
mov r9,#0 @ 0 final
strb r9,[r2,r5]
mov r0,r5
100:
pop {r3-r11,pc} @ restaur registers
/***************************************************/
/* ROUTINES INCLUDE */
/***************************************************/
.include "../affichage.inc"- Output:
Program 32 bits start. String : ATTACKATDAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN String : FLEEATONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE String : ATTACKATDAWN Encrypted : EYFENGIWDILA Decrypted : ATTACKATDAWN String : L'invasion commencera le premier janvier Encrypted : MPDHLNLLDCCQMDFPFQSAOSOGXPFEWWUICDW Decrypted : LINVASIONCOMMENCERALEPREMIERIANVIER Program normal end.
BASIC
Applesoft BASIC
100 A$ = "ATTACKATDAWN": GOSUB 160"REPORT
110 K$ = "BGWKZQPNDSIOAXEFCLUMTHYVR"
120 A$ = "FLEEATONCE": GOSUB 160"REPORT
130 K$ = " .'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123"
140 A$ = "THE INVASION WILL START ON THE FIRST OF JANUARY 2023.": GOSUB 160"REPORT
150 END
REM REPORT
160 GOSUB 200"ENCRYPT
165 PRINT M$M$"FOR "W" X "W" POLYBIUS:":M$ = CHR$ (13): FOR I = 1 TO W: PRINT , MID$ (K$,(I - 1) * W + 1,W): NEXT
170 PRINT "ENCRYPTED: "E$
180 GOSUB 300"DECRYPT
190 PRINT "DECRYPTED: "U$;: RETURN
REM ENCRYPT A$ RETURNS E$
200 GOSUB 400:L = LEN (A$):E$ = "":U$ = "": IF NOT L THEN RETURN
210 FOR I = 1 TO L
220 C = ASC ( MID$ (A$,I,1)): IF X(C) AND Y(C) THEN U$ = U$ + CHR$ (C)
230 NEXT I
240 L = LEN (U$): IF NOT L THEN RETURN
250 FOR I = 1 TO L:C = ASC ( MID$ (U$,I,1)):A(I) = X(C):A(I + L) = Y(C): NEXT I
260 FOR I = 1 TO L * 2 STEP 2:E$ = E$ + MID$ (K$,(A(I) - 1) * W + A(I + 1),1): NEXT I
270 RETURN
REM DECRYPT E$ RETURNS U$
300 GOSUB 400:L = LEN (E$):U$ = "": IF NOT L THEN RETURN
310 FOR I = 1 TO L:C = ASC ( MID$ (E$,I)):B(I * 2 - 1) = X(C):B(I * 2) = Y(C): NEXT I
320 FOR I = 1 TO L:U$ = U$ + MID$ (K$,(B(I) - 1) * W + B(L + I),1): NEXT I
330 RETURN
REM POLYBIUS K$ RETURNS X(255),Y(255)
400 IF K$ = P$ AND LEN (K$) THEN RETURN
410 IF XY THEN FOR I = 0 TO 255:X(I) = 0:Y(I) = 0: NEXT I
420 IF NOT XY THEN DIM X(255),Y(255),A(512),B(512):XY = 1
430 IF K$ = "" THEN FOR I = 1 TO 25:K$ = K$ + CHR$ (I + 64 + (I > 9)): NEXT I
440 L = LEN (K$):W = INT ( SQR (L - 1) + 1):I = 1:N = 1:K = ASC ("0")
450 FOR X = 1 TO W
460 FOR Y = 1 TO W
470 C$ = MID$ (K$,I,1): IF C$ = "" THEN FOR C = K TO 255: IF X(C) THEN NEXT C: STOP
480 IF C$ = "" THEN C$ = CHR$ (C):K$ = K$ + C$:K = C + 1
490 C = ASC (C$):Y(C) = Y:X(C) = X:I = I + 1: IF C$ = "J" THEN N = 0
500 NEXT Y,X
510 IF N THEN Y( ASC ("J")) = Y( ASC ("I")):X( ASC ("J")) = X( ASC ("I"))
520 P$ = K$
530 RETURN
- Output:
FOR 5 X 5 POLYBIUS:
ABCDE
FGHIK
LMNOP
QRSTU
VWXYZ
ENCRYPTED: DQBDAXDQPDQH
DECRYPTED: ATTACKATDAWN
FOR 5 X 5 POLYBIUS:
BGWKZ
QPNDS
IOAXE
FCLUM
THYVR
ENCRYPTED: UAEOLWRINS
DECRYPTED: FLEEATONCE
FOR 6 X 6 POLYBIUS:
.'ABC
DEFGHI
JKLMNO
PQRSTU
VWXYZ0
123456
ENCRYPTED: QDFVQLBFJSAPLAE.GS'DJMAV56BWCVS6VILAYNCVZDOMV3 T4M.2K
DECRYPTED: THE INVASION WILL START ON THE FIRST OF JANUARY 2023.
C#
using System;
using System.Collections.Generic;
using System.Drawing;
public class BifidCipher
{
public static void Main(string[] args)
{
string message1 = "ATTACKATDAWN";
string message2 = "FLEEATONCE";
string message3 = "The invasion will start on the first of January".ToUpper().Replace(" ", "");
Bifid bifid1 = new Bifid(5, "ABCDEFGHIKLMNOPQRSTUVWXYZ");
Bifid bifid2 = new Bifid(5, "BGWKZQPNDSIOAXEFCLUMTHYVR");
RunTest(bifid1, message1);
RunTest(bifid2, message2);
RunTest(bifid2, message1);
RunTest(bifid1, message2);
Bifid bifid3 = new Bifid(6, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789");
RunTest(bifid3, message3);
}
private static void RunTest(Bifid bifid, string message)
{
Console.WriteLine("Using Polybius square:");
bifid.Display();
Console.WriteLine("Message: " + message);
string encrypted = bifid.Encrypt(message);
Console.WriteLine("Encrypted: " + encrypted);
string decrypted = bifid.Decrypt(encrypted);
Console.WriteLine("Decrypted: " + decrypted);
Console.WriteLine();
}
}
public class Bifid
{
private char[,] grid;
private Dictionary<char, Point> coordinates = new Dictionary<char, Point>();
public Bifid(int n, string text)
{
if (text.Length != n * n)
{
throw new ArgumentException("Incorrect length of text");
}
grid = new char[n, n];
int row = 0;
int col = 0;
foreach (char ch in text)
{
grid[row, col] = ch;
coordinates[ch] = new Point(row, col);
col += 1;
if (col == n)
{
col = 0;
row += 1;
}
}
if (n == 5)
{
coordinates['J'] = coordinates['I'];
}
}
public string Encrypt(string text)
{
List<int> rowOne = new List<int>();
List<int> rowTwo = new List<int>();
foreach (char ch in text)
{
Point coordinate = coordinates[ch];
rowOne.Add(coordinate.X);
rowTwo.Add(coordinate.Y);
}
rowOne.AddRange(rowTwo);
var result = new System.Text.StringBuilder();
for (int i = 0; i < rowOne.Count - 1; i += 2)
{
result.Append(grid[rowOne[i], rowOne[i + 1]]);
}
return result.ToString();
}
public string Decrypt(string text)
{
List<int> row = new List<int>();
foreach (char ch in text)
{
Point coordinate = coordinates[ch];
row.Add(coordinate.X);
row.Add(coordinate.Y);
}
int middle = row.Count / 2;
List<int> rowOne = row.GetRange(0, middle);
List<int> rowTwo = row.GetRange(middle, row.Count - middle);
var result = new System.Text.StringBuilder();
for (int i = 0; i < middle; i++)
{
result.Append(grid[rowOne[i], rowTwo[i]]);
}
return result.ToString();
}
public void Display()
{
for (int i = 0; i < grid.GetLength(0); i++)
{
for (int j = 0; j < grid.GetLength(1); j++)
{
Console.Write(grid[i, j] + " ");
}
Console.WriteLine();
}
}
}
- Output:
Using Polybius square: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message: ATTACKATDAWN Encrypted: DQBDAXDQPDQH Decrypted: ATTACKATDAWN Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message: FLEEATONCE Encrypted: UAEOLWRINS Decrypted: FLEEATONCE Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message: ATTACKATDAWN Encrypted: EYFENGIWDILA Decrypted: ATTACKATDAWN Using Polybius square: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message: FLEEATONCE Encrypted: HADNAAZDSP Decrypted: FLEEATONCE Using Polybius square: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 Message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY Encrypted: TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4 Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
C++
#include <cstdint>
#include <iostream>
#include <stdexcept>
#include <string_view>
#include <unordered_map>
#include <vector>
typedef std::pair<int32_t, int32_t> point;
class Bifid {
public:
Bifid(const int32_t n, std::string_view text) {
if ( text.length() != n * n ) {
throw std::invalid_argument("Incorrect length of text");
}
grid.resize(n);
for ( uint64_t i = 0; i < grid.size(); i++ ) {
grid[i].resize(n);
}
int32_t row = 0;
int32_t col = 0;
for ( const char& ch : text ) {
grid[row][col] = ch;
coordinates[ch] = point(row, col);
col += 1;
if ( col == n ) {
col = 0;
row += 1;
}
}
if ( n == 5 ) {
coordinates['J'] = coordinates['I'];
}
}
std::string encrypt(std::string_view text) {
std::vector<int32_t> row_one, row_two;
for ( const char& ch : text ) {
point coordinate = coordinates[ch];
row_one.push_back(coordinate.first);
row_two.push_back(coordinate.second);
}
row_one.insert(row_one.end(), row_two.begin(), row_two.end());
std::string result;
for ( uint64_t i = 0; i < row_one.size() - 1; i += 2 ) {
result += grid[row_one[i]][row_one[i + 1]];
}
return result;
}
std::string decrypt(std::string_view text) {
std::vector<int32_t> row;
for ( const char& ch : text ) {
point coordinate = coordinates[ch];
row.push_back(coordinate.first);
row.push_back(coordinate.second);
}
const int middle = row.size() / 2;
std::vector<int32_t> row_one = { row.begin(), row.begin() + middle };
std::vector<int32_t> row_two = { row.begin() + middle, row.end() };
std::string result;
for ( int32_t i = 0; i < middle; i++ ) {
result += grid[row_one[i]][row_two[i]];
}
return result;
}
void display() const {
for ( const std::vector<char>& row : grid ) {
for ( const char& ch : row ) {
std::cout << ch << " ";
}
std::cout << std::endl;
}
}
private:
std::vector<std::vector<char>> grid;
std::unordered_map<char, point> coordinates;
};
void runTest(Bifid& bifid, std::string_view message) {
std::cout << "Using Polybius square:" << std::endl;
bifid.display();
std::cout << "Message: " << message << std::endl;
std::string encrypted = bifid.encrypt(message);
std::cout << "Encrypted: " << encrypted << std::endl;
std::string decrypted = bifid.decrypt(encrypted);
std::cout << "Decrypted: " << decrypted << std::endl;
std::cout << std::endl;
}
int main() {
const std::string_view message1 = "ATTACKATDAWN";
const std::string_view message2 = "FLEEATONCE";
const std::string_view message3 = "THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY";
Bifid bifid1(5, "ABCDEFGHIKLMNOPQRSTUVWXYZ");
Bifid bifid2(5, "BGWKZQPNDSIOAXEFCLUMTHYVR");
runTest(bifid1, message1);
runTest(bifid2, message2);
runTest(bifid2, message1);
runTest(bifid1, message2);
Bifid bifid3(6, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789");
runTest(bifid3, message3);
}
- Output:
Using Polybius square: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message: ATTACKATDAWN Encrypted: DQBDAXDQPDQH Decrypted: ATTACKATDAWN Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message: FLEEATONCE Encrypted: UAEOLWRINS Decrypted: FLEEATONCE Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message: ATTACKATDAWN Encrypted: EYFENGIWDILA Decrypted: ATTACKATDAWN Using Polybius square: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message: FLEEATONCE Encrypted: HADNAAZDSP Decrypted: FLEEATONCE Using Polybius square: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 Message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY Encrypted: TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4 Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
EasyLang
proc prepare . s$ .
for e$ in strchars s$
h = strcode e$
if h >= 97
h -= 32
.
if h >= 65 and h <= 91
if h = 74
h = 73
.
r$ &= strchar h
.
.
swap s$ r$
.
func$ encr msg$ key$ .
prepare msg$
len h[] len msg$ * 2
for i to len msg$
c$ = substr msg$ i 1
j = strpos key$ c$ - 1
h[i] = j div 5
h[len msg$ + i] = j mod 5
.
for i = 1 step 2 to len h[] - 1
j = h[i] * 5 + h[i + 1] + 1
r$ &= substr key$ j 1
.
return r$
.
func$ decr msg$ key$ .
for i to len msg$
c$ = substr msg$ i 1
j = strpos key$ c$ - 1
h[] &= j div 5
h[] &= j mod 5
.
mid = len h[] div 2
for i = 1 to mid
j = h[i] * 5 + h[i + mid] + 1
r$ &= substr key$ j 1
.
return r$
.
key$ = "ABCDEFGHIKLMNOPQRSTUVWXYZ"
h$ = encr "ATTACKATDAWN" key$
print h$
print decr h$ key$
print ""
#
key$ = "BGWKZQPNDSIOAXEFCLUMTHYVR"
h$ = encr "FLEEATONCE" key$
print h$
print decr h$ key$
print ""
h$ = encr "ATTACKATDAWN" key$
print h$
print decr h$ key$
print ""
h$ = encr "The invasion will start on the first of January" key$
print h$
print decr h$ key$
- Output:
DQBDAXDQPDQH ATTACKATDAWN UAEOLWRINS FLEEATONCE EYFENGIWDILA ATTACKATDAWN RASOAQXCYRORXESXADETSWLTNIATEGISBRGBALY THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
EMal
type PolybiusSquare
model
Map map
List grid
new by int side, text symbols
me.map ← text%Pair[]
me.grid ← List[].with(side, <int y|text[].with(side, <int x|""))
int y, x ← 0
for each text symbol in symbols
me.grid[y][x] ← symbol
me.map[symbol] ← int%int(y => x).named("y", "x")
x++
if x æ side
x ← 0
y++
end
end
end
fun asText = text by block
text result = ""
for int y ← 0; y < me.grid.length; y++
for int x ← 0; x < me.grid[y].length; x++
result.append(" " + me.grid[y][x])
end
result.appendLine()
end
return result
end
end
type BifidCipher
model
PolybiusSquare square
new by PolybiusSquare ←square do end
fun encrypt ← text by text value
List row ← int[].with(value.length * 2)
int y ← 0
int x ← value.length
for each text char in value
Pair p ← me.square.map[char]
row[y++] ← p.y
row[x++] ← p.x
end
text encrypted
for int i ← 0; i < row.length; i += 2
encrypted.append(me.square.grid[row[i]][row[i + 1]])
end
return encrypted
end
fun decrypt ← text by text value
List row ← int[]
for each text char in value
Pair p ← me.square.map[char]
row.append(p.y)
row.append(p.x)
end
int y ← 0
int x ← value.length
text decrypted
for int i ← 0; i < value.length; i++
decrypted.append(me.square.grid[row[y++]][row[x++]])
end
return decrypted
end
end
type Main
List pairs ← Pair[
text%PolybiusSquare("ATTACKATDAWN" => PolybiusSquare(5, "ABCDEFGHIKLMNOPQRSTUVWXYZ")).named("sample", "square"),
text%PolybiusSquare("FLEEATONCE" => PolybiusSquare(5, "BGWKZQPNDSIOAXEFCLUMTHYVR")).named("sample", "square"),
text%PolybiusSquare("ATTACKATDAWN" => PolybiusSquare(5, "BGWKZQPNDSIOAXEFCLUMTHYVR")).named("sample", "square"),
text%PolybiusSquare("The invasion will start on the first of January".upper().replace(" ", "") =>
PolybiusSquare(6, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")).named("sample", "square")]
for each Pair pair in pairs
writeLine("Using Polybius square:")
write(pair.square)
BifidCipher cipher ← BifidCipher(pair.square)
write("Encrypting '" + pair.sample + "'")
text encrypted ← cipher.encrypt(pair.sample)
write(" => '" + encrypted + "'")
text decrypted ← cipher.decrypt(encrypted)
writeLine(" => '" + decrypted + "'")
writeLine()
end- Output:
Using Polybius square: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Encrypting 'ATTACKATDAWN' => 'DQBDAXDQPDQH' => 'ATTACKATDAWN' Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Encrypting 'FLEEATONCE' => 'UAEOLWRINS' => 'FLEEATONCE' Using Polybius square: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Encrypting 'ATTACKATDAWN' => 'EYFENGIWDILA' => 'ATTACKATDAWN' Using Polybius square: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9 Encrypting 'THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY' => 'TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4' => 'THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY'
F#
// Bifid cipher. Nigel Galloway: September 17th., 2024
let polybius alphabet n g=let ng=Seq.allPairs [1..n] [1..g] in (Seq.zip ng alphabet|>Map.ofSeq,Seq.zip alphabet ng|>Map.ofSeq)
let fN (i,g) (e:Map<(int*int),char>)=i@g|>List.chunkBySize 2|>List.map(fun n->e[(n[0],n[1])])|>Array.ofList|>System.String
let fG (n:Map<char,int*int>) g=g|>Seq.map(fun g->n[g])|>List.ofSeq|>List.unzip
let encrypt (n:Map<(int * int),char>,g:Map<char,(int * int)>) text=fN (fG g text) n
let decrypt (n:Map<(int * int),char>,g:Map<char,(int * int)>) text=
let p,q=let p,q=fG g text in List.map2(fun p q->[p;q]) p q|>List.concat|>List.splitAt p.Length
List.zip p q |>List.map(fun g->n[g])|>Array.ofList|>System.String
let p1=polybius "abcdefghiklmnopqrstuvwxyz" 5 5
let s="attackatdawn" in let e=encrypt p1 s in printfn $"%s{s} -> %s{e} -> %s{decrypt p1 e}"
let s="fleeatonce" in let e=encrypt p1 s in printfn $"%s{s} -> %s{e} -> %s{decrypt p1 e}"
let p2=polybius "bgwkzqpndsioaxefclumthyvr" 5 5
let s="attackatdawn" in let e=encrypt p2 s in printfn $"%s{s} -> %s{e} -> %s{decrypt p2 e}"
let s="fleeatonce" in let e=encrypt p2 s in printfn $"%s{s} -> %s{e} -> %s{decrypt p2 e}"
let p3=polybius "abcdefghijklmnopqrstuvwxyz0123456789" 6 6
let s="theinvasionwillstarton1january2025" in let e=encrypt p3 s in printfn $"%s{s} -> %s{e} -> %s{decrypt p3 e}"
- Output:
attackatdawn -> dqbdaxdqpdqh -> attackatdawn fleeatonce -> hadnaazdsp -> fleeatonce attackatdawn -> eyfengiwdila -> attackatdawn fleeatonce -> uaeolwrins -> fleeatonce theinvasionwillstarton1january2025 -> tbpdiphjspozcsq23h0jaokr4g5nvbm40z -> theinvasionwillstarton1january2025
FutureBasic
clear local fn recode( t as CFStringRef, code as CFStringRef ) as CFStringRef
CFStringRef s = @""
Short i, k, w = sqr( len( code ) )
for i = 0 to len( t ) - 1 step 2
k = intval( mid( t, i, 2 ) ) // Get ‘coordinates’ of char in code string
k = w * ( k / 10 ) + k mod 10
s = fn StringByAppendingString( s, mid( code, k, 1 ) )
next
end fn = s
//
clear local fn encode( s as CFStringRef, code as CFStringRef ) as CFStringRef
CFStringRef a = @"", b = @"", c
Short i, k, w = sqr( len( code ) )
if w == 5 then s = fn StringByReplacingOccurrencesOfString( s, @"J", @"I" )
print s
for i = 0 to len( s ) - 1
c = mid( s, i, 1 )
k = instr( 0, code, c ) // Put row in one string, column in the other
a = fn StringByAppendingString( a, fn StringWithFormat( @"%d", k / w ) )
b = fn StringByAppendingString( b, fn StringWithFormat( @"%d", k mod w ) )
next
a = fn StringByAppendingString( a, b ) // Combine the two strings, and recode
end fn = fn recode( a, code )
//
clear local fn decode( s as CFStringRef, code as CFStringRef ) as CFStringRef
CFStringRef a = @"", b = @"", c
Short i, k, w = sqr( len( code ) )
for i = 0 to ( len( s ) - 1 )
c = mid( s, i, 1 )
k = instr( 0, code, c ) // Put row and columm in one long string
a = fn StringByAppendingString( a, fn StringWithFormat( @"%d%d", k / w, k mod w ) )
next
for i = 0 to len( a ) / 2 - 1 // Take row from first half of string, column from second
c = fn StringByAppendingString( mid( a, i, 1 ), mid( a, i + len( a ) / 2 , 1 ) )
b = fn StringByAppendingString( b , c ) // Combine, and recode
next
end fn = fn recode( b, code )
//
print fn encode( @"ATTACKATDAWN", @"ABCDEFGHIKLMNOPQRSTUVWXYZ" )
print fn decode( @"DQBDAXDQPDQH", @"ABCDEFGHIKLMNOPQRSTUVWXYZ" )
print
print fn encode( @"FLEEATONCE", @"BGWKZQPDNSIOAXEFCLUMTHYVR" )
print fn decode( @"UAEOLWRINS", @"BGWKZQPDNSIOAXEFCLUMTHYVR" )
print
print fn encode( @"HAPPY40THDAD", @"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" )
print fn decode( @"GO31GAGVANJD", @"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" )
handleevents- Output:
ATTACKATDAWN DQBDAXDQPDQH ATTACKATDAWN FLEEATONCE UAEOLWRINS FLEEATONCE HAPPY40THDAD GO31GAGVANJD HAPPY40THDAD
J
Implementation:
alpha=: a.{~65+i.26
normalize=: {{ rplc&'JI'(toupper y)([-.-.)alpha }}
bifid=: {{ m{~_2 (t&#.)\,|:(t,t=.%:#m)#:m i.y([-.-.)m }}
difib=: {{ m{~t#.|:(|.@$$,)(t,t=.%:#m)#:m i.y([-.-.)m }}
This is pretty much a literal implementation of the algorithm, except that our indices range from 0..4 instead of 1..5 (or, for letter indices, they range from 0..24 instead of 1..25).
Much of the implementation is about converting between a two digit base 5 representation and a single digit numeric representation. The rest is simple array manipulations to make the rest come out right.
Task examples:
ref1=: ~.normalize alpha
ref2=: 'BGWKZQPNDSIOAXEFCLUMTHYVR'
ref3=: 'PLAYFIREXMBCDGHKNOQSTUVWZ'
ref1 bifid normalize 'attack at dawn'
DQBDAXDQPDQH
ref1 difib ref1 bifid normalize 'attack at dawn'
ATTACKATDAWN
ref2 bifid normalize 'flee at once'
UAEOLWRINS
ref2 difib ref2 bifid normalize 'flee at once'
FLEEATONCE
ref2 bifid normalize 'attack at dawn'
EYFENGIWDILA
ref2 difib ref2 bifid normalize 'attack at dawn'
ATTACKATDAWN
ref3 bifid normalize 'The invasion will start on the first of January'
VRSYXSIYTMQVIRSKISLPVLDTCKRTCAIVTMATCEX
ref3 difib ref3 bifid normalize 'The invasion will start on the first of January'
THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
(_81{.123{.a.)bifid 'The invasion will start on the first of January'
TgqhpqpqxzpxfqzoKqhxw/O3eWH53BYw`+Be8F1
(_81{.123{.a.)difib(_81{.123{.a.)bifid 'The invasion will start on the first of January'
TheinvasionwillstartonthefirstofJanuary
Java
import java.awt.Point;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public final class BifidCipher {
public static void main(String[] aArgs) {
final String message1 = "ATTACKATDAWN";
final String message2 = "FLEEATONCE";
final String message3 = "The invasion will start on the first of January".toUpperCase().replace(" ", "");
Bifid bifid1 = new Bifid(5, "ABCDEFGHIKLMNOPQRSTUVWXYZ");
Bifid bifid2 = new Bifid(5, "BGWKZQPNDSIOAXEFCLUMTHYVR");
runTest(bifid1, message1);
runTest(bifid2, message2);
runTest(bifid2, message1);
runTest(bifid1, message2);
Bifid bifid3 = new Bifid(6, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789");
runTest(bifid3, message3);
}
private static void runTest(Bifid aBifid, String aMessage) {
System.out.println("Using Polybius square:");
aBifid.display();
System.out.println("Message: " + aMessage);
String encrypted = aBifid.encrypt(aMessage);
System.out.println("Encrypted: " + encrypted);
String decrypted = aBifid.decrypt(encrypted);
System.out.println("Decrypted: " + decrypted);
System.out.println();
}
}
final class Bifid {
public Bifid(int aN, String aText) {
if ( aText.length() != aN * aN ) {
throw new IllegalArgumentException("Incorrect length of text");
}
grid = new char[aN][aN];
int row = 0;
int col = 0;
for ( char ch : aText.toCharArray() ) {
grid[row][col] = ch;
coordinates.put(ch, new Point(row, col) );
col += 1;
if ( col == aN ) {
col = 0;
row += 1;
}
}
if ( aN == 5 ) {
coordinates.put('J', coordinates.get('I'));
}
}
public String encrypt(String aText) {
List<Integer> rowOne = new ArrayList<Integer>();
List<Integer> rowTwo = new ArrayList<Integer>();
for ( char ch : aText.toCharArray() ) {
Point coordinate = coordinates.get(ch);
rowOne.add(coordinate.x);
rowTwo.add(coordinate.y);
}
rowOne.addAll(rowTwo);
StringBuilder result = new StringBuilder();
for ( int i = 0; i < rowOne.size() - 1; i += 2 ) {
result.append(grid[rowOne.get(i)][rowOne.get(i + 1)]);
}
return result.toString();
}
public String decrypt(String aText) {
List<Integer> row = new ArrayList<Integer>();
for ( char ch : aText.toCharArray() ) {
Point coordinate = coordinates.get(ch);
row.add(coordinate.x);
row.add(coordinate.y);
}
final int middle = row.size() / 2;
List<Integer> rowOne = row.subList(0, middle);
List<Integer> rowTwo = row.subList(middle, row.size());
StringBuilder result = new StringBuilder();
for ( int i = 0; i < middle; i++ ) {
result.append(grid[rowOne.get(i)][rowTwo.get(i)]);
}
return result.toString();
}
public void display() {
Arrays.stream(grid).forEach( row -> System.out.println(Arrays.toString(row)) );
}
private char[][] grid;
private Map<Character, Point> coordinates = new HashMap<Character, Point>();
}
- Output:
Using Polybius square: [A, B, C, D, E] [F, G, H, I, K] [L, M, N, O, P] [Q, R, S, T, U] [V, W, X, Y, Z] Message: ATTACKATDAWN Encrypted: DQBDAXDQPDQH Decrypted: ATTACKATDAWN Using Polybius square: [B, G, W, K, Z] [Q, P, N, D, S] [I, O, A, X, E] [F, C, L, U, M] [T, H, Y, V, R] Message: FLEEATONCE Encrypted: UAEOLWRINS Decrypted: FLEEATONCE Using Polybius square: [B, G, W, K, Z] [Q, P, N, D, S] [I, O, A, X, E] [F, C, L, U, M] [T, H, Y, V, R] Message: ATTACKATDAWN Encrypted: EYFENGIWDILA Decrypted: ATTACKATDAWN Using Polybius square: [A, B, C, D, E] [F, G, H, I, K] [L, M, N, O, P] [Q, R, S, T, U] [V, W, X, Y, Z] Message: FLEEATONCE Encrypted: HADNAAZDSP Decrypted: FLEEATONCE Using Polybius square: [A, B, C, D, E, F] [G, H, I, J, K, L] [M, N, O, P, Q, R] [S, T, U, V, W, X] [Y, Z, 0, 1, 2, 3] [4, 5, 6, 7, 8, 9] Message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY Encrypted: TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4 Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
jq
Adapted from Wren
Also works with gojq, the Go implementation of jq.
Preliminaries
# _nwise is for gojq
def _nwise($n):
def n: if length <= $n then . else .[0:$n] , (.[$n:] | n) end;
n;
# Input: a string
# Output: a stream of strings
def chars: explode[] | [.] | implode;Bifid
# Input: the message to be encrypted
def encrypt($polybius):
(ascii_upcase | gsub("J"; "I") ) as $m
| {rows: [], cols : [] }
| reduce ($m|chars) as $c (.;
($polybius|index($c)) as $ix
| if $ix
then .rows += [($ix/5)|floor + 1]
| .cols += [($ix%5) + 1]
else .
end )
| reduce (.rows + .cols | _nwise(2)) as $pair ("";
(($pair[0] - 1) * 5 + $pair[1] - 1) as $ix
| . + $polybius[$ix:$ix+1] ) ;
# Input: the message to be decrypted
def decrypt($polybius):
reduce chars as $c ( {rows: [], cols : [] };
($polybius|index($c)) as $ix
| .rows += [($ix/5)|floor + 1]
| .cols += [($ix%5) + 1] )
| ([.rows, .cols] | transpose | flatten) as $lines
| ($lines|length/2) as $count
| $lines[:$count] as $rows
| $lines[$count:] as $cols
| [$rows, $cols] as $d
| reduce range(0; $count) as $i ("";
(($rows[$i] - 1) * 5 + $cols[$i] - 1) as $ix
| . + $polybius[$ix:$ix+1] ) ;
def polys:
def p1: "ABCDEFGHIKLMNOPQRSTUVWXYZ";
def p2: "BGWKZQPNDSIOAXEFCLUMTHYVR";
def p3: "PLAYFIREXMBCDGHKNOQSTUVWZ";
[p1, p2, p2, p3];
def messages: [
"ATTACKATDAWN",
"FLEEATONCE",
"ATTACKATDAWN",
"The invasion will start on the first of January"
];
def task:
range(0; messages|length) as $i
| messages[$i]
| encrypt(polys[$i]) as $encrypted
| ($encrypted | decrypt(polys[$i] )) as $decrypted
| "Message : \(.)",
"Encrypted : \($encrypted)",
"Decrypted : \($decrypted)"
"" ;
task- Output:
Same as for #Wren.
Julia
Using the Raku example's test messages.
polybius(text) = Char.(reshape(Int.(collect(text)), isqrt(length(text)), :)')
function encrypt(message, poly)
positions = [findall(==(c), poly)[1] for c in message]
numbers = vcat([c[1] for c in positions], [c[2] for c in positions])
return String([poly[numbers[i], numbers[i+1]] for i in 1:2:length(numbers)-1])
end
function decrypt(message, poly)
n = length(message)
positions = [findall(==(c), poly)[1] for c in message]
numbers = reduce(vcat, [[c[1], c[2]] for c in positions])
return String([poly[numbers[i], numbers[i+n]] for i in 1:n])
end
for (key, text) in [("ABCDEFGHIKLMNOPQRSTUVWXYZ", "ATTACKATDAWN"), ("BGWKZQPNDSIOAXEFCLUMTHYVR", "FLEEATONCE"),
([' '; '.'; 'A':'Z'; 'a':'z'; '0':'9'], "The invasion will start on the first of January 2023.")]
poly = polybius(key)
encrypted = encrypt(text, poly)
decrypted = decrypt(encrypted, poly)
println("Using polybius:")
display(poly)
println("\n Message: $text\n Encrypted: $encrypted\n Decrypted: $decrypted\n\n")
end
- Output:
Using polybius:
5×5 Matrix{Char}:
'A' 'B' 'C' 'D' 'E'
'F' 'G' 'H' 'I' 'K'
'L' 'M' 'N' 'O' 'P'
'Q' 'R' 'S' 'T' 'U'
'V' 'W' 'X' 'Y' 'Z'
Message: ATTACKATDAWN
Encrypted: DQBDAXDQPDQH
Decrypted: ATTACKATDAWN
Using polybius:
5×5 Matrix{Char}:
'B' 'G' 'W' 'K' 'Z'
'Q' 'P' 'N' 'D' 'S'
'I' 'O' 'A' 'X' 'E'
'F' 'C' 'L' 'U' 'M'
'T' 'H' 'Y' 'V' 'R'
Message: FLEEATONCE
Encrypted: UAEOLWRINS
Decrypted: FLEEATONCE
Using polybius:
8×8 Matrix{Char}:
' ' '.' 'A' 'B' 'C' 'D' 'E' 'F'
'G' 'H' 'I' 'J' 'K' 'L' 'M' 'N'
'O' 'P' 'Q' 'R' 'S' 'T' 'U' 'V'
'W' 'X' 'Y' 'Z' 'a' 'b' 'c' 'd'
'e' 'f' 'g' 'h' 'i' 'j' 'k' 'l'
'm' 'n' 'o' 'p' 'q' 'r' 's' 't'
'u' 'v' 'w' 'x' 'y' 'z' '0' '1'
'2' '3' '4' '5' '6' '7' '8' '9'
Message: The invasion will start on the first of January 2023.
Encrypted: SejxqrEierbmrDiCjrDeJsbu89DWCHkgGS9E6tAG5 Ks2PBfCq uH
Decrypted: The invasion will start on the first of January 2023.
Kotlin
import kotlin.math.sqrt
data class Square(private val square: String) {
private val dim: Int =
sqrt(square.length.toDouble()).toInt()
fun encode(ch: Char): Pair<Int, Int> =
square.indexOf(ch).let { idx -> Pair(idx / dim, idx.mod(dim)) }
fun decode(pair: List<Int>): Char =
square[pair[0] * dim + pair[1]]
fun decode(row: Int, col: Int): Char =
square[row * dim + col]
}
class Bifid(private val square: Square) {
fun encrypt(str: String): String {
fun expandAndScatter(str: String): IntArray {
val buffer = IntArray(str.length * 2)
str.forEachIndexed { i, ch ->
with(square.encode(ch)) {
buffer[i] = first
buffer[str.length + i] = second
}
}
return buffer
}
val buffer = expandAndScatter(str)
val characters: List<Char> = buffer.asIterable()
.windowed(size = 2, step = 2)
.map { square.decode(it) }
return String(characters.toCharArray())
}
fun decrypt(str: String): String {
fun expand(str: String): IntArray {
val buffer = IntArray(str.length * 2)
for (i in buffer.indices step 2) {
with(square.encode(str[i / 2])) {
buffer[i] = first
buffer[1 + i] = second
}
}
return buffer
}
val buffer = expand(str)
val characters = str.toCharArray()
for (i in characters.indices) {
characters[i] = square.decode(buffer[i], buffer[characters.size + i])
}
return String(characters)
}
}
fun main() {
with (Bifid(Square("ABCDEFGHIKLMNOPQRSTUVWXYZ"))) {
println("\n### ABC... 5x5")
encrypt("ATTACKATDAWN").also { println("ATTACKATDAWN -> $it") }
decrypt("DQBDAXDQPDQH").also { println("DQBDAXDQPDQH -> $it") }
}
with(Bifid(Square("BGWKZQPNDSIOAXEFCLUMTHYVR"))) {
println("\n### BGW... 5x5")
encrypt("FLEEATONCE").also { println("FLEEATONCE -> $it") }
decrypt("UAEOLWRINS").also { println("UAEOLWRINS -> $it") }
encrypt("ATTACKATDAWN").also { println("ATTACKATDAWN -> $it") }
decrypt("EYFENGIWDILA").also { println("EYFENGIWDILA -> $it") }
}
with(Bifid(Square("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"))) {
println("\n### ABC... 6x6")
encrypt("THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY").also { println("$it") }
decrypt("TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4").also { println("$it") }
}
}
- Output:
### ABC... 5x5 ATTACKATDAWN -> DQBDAXDQPDQH DQBDAXDQPDQH -> ATTACKATDAWN ### BGW... 5x5 FLEEATONCE -> UAEOLWRINS UAEOLWRINS -> FLEEATONCE ATTACKATDAWN -> EYFENGIWDILA EYFENGIWDILA -> ATTACKATDAWN ### ABC... 6x6 TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4 THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
Lua
The "In addition" task and the bonus task are both solved using a 6x6 Polybius square containing every captial letter and all ten digits.
I refer to this combined solution as 'Task 4'.
function transcipher (cipher, message, decipher)
local message = message:gsub("%s+", ""):upper()
local xStr, yStr, s, char = "", "", ""
for pos = 1, #message do
char = message:sub(pos, pos)
for x = 1, #cipher do
for y = 1, #cipher[x] do
if cipher[x][y] == char then
s = s .. x .. y
xStr = xStr .. x
yStr = yStr .. y
end
end
end
end
if decipher then
xStr, yStr = s:sub(1, #s/2), s:sub(#s/2 + 1, #s)
else
s = xStr .. yStr
end
local result, x, y = ""
local limit = decipher and #s/2 or #s
local step = decipher and 1 or 2
for pos = 1, limit, step do
x = tonumber(s:sub(pos, pos))
y = decipher and
tonumber(s:sub(pos + #s/2, pos + #s/2)) or
tonumber(s:sub(pos + 1, pos + 1))
result = result .. cipher[x][y]
end
return result
end
local RCbifid = {
{"A", "B", "C", "D", "E"},
{"F", "G", "H", "I", "K"},
{"L", "M", "N", "O", "P"},
{"Q", "R", "S", "T", "U"},
{"V", "W", "X", "Y", "Z"}
}
local wikibifid = {
{"B", "G", "W", "K", "Z"},
{"Q", "P", "N", "D", "S"},
{"I", "O", "A", "X", "E"},
{"F", "C", "L", "U", "M"},
{"T", "H", "Y", "V", "R"}
}
local mybifid = {
{"A", "B", "C", "D", "E", "F"},
{"G", "H", "I", "J", "K", "L"},
{"M", "N", "O", "P", "Q", "R"},
{"S", "T", "U", "V", "W", "X"},
{"Y", "Z", "1", "2", "3", "4"},
{"5", "6", "7", "8", "9", "0"}
}
local testCases = {
{RCbifid, "ATTACKATDAWN"},
{wikibifid, "FLEEATONCE"},
{wikibifid, "ATTACKATDAWN",},
{mybifid, "The invasion will start on the first of January"}
}
local msg
for task, case in pairs(testCases) do
print("\nTask " .. task)
msg = transcipher(case[1], case[2])
print("Encoded message: " .. msg)
msg = transcipher(case[1], msg, true)
print("Decoded message: " .. msg)
end
- Output:
Task 1 Encoded message: DQBDAXDQPDQH Decoded message: ATTACKATDAWN Task 2 Encoded message: UAEOLWRINS Decoded message: FLEEATONCE Task 3 Encoded message: EYFENGIWDILA Decoded message: ATTACKATDAWN Task 4 Encoded message: TBPDIPHJSPOTAIVMGPCZKNSCN10BFIHK75I8BM5 Decoded message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
Nim
To add the letter J, we use a 6x6 Polybius square containing the 26 letters and the 10 digits. To build the square, we use a generic type parameterized with the side length.
import std/[sequtils, strutils, tables]
# Description of a Bifid cipher.
type Bifid[N: static Positive] = object
grid: array[1..N, array[1..N, char]]
coords: Table[char, (int, int)]
proc initBifid(N: static Positive; text: string): Bifid[N] =
# Initialize a Bifid cipher.
assert text.len == N * N
var row, col = 1
for c in text:
result.grid[row][col] = c
result.coords[c] = (row, col)
inc col
if col > N:
col = 1
inc row
if N == 5:
result.coords['J'] = result.coords['I']
func encrypt(bifid: Bifid; text: string): string =
## Encrypt "text" using the given cipher.
var row1, row2: seq[int]
for ch in text:
let coords = bifid.coords[ch]
row1.add coords[0]
row2.add coords[1]
let row = row1 & row2
for i in countup(0, row.high, 2):
result.add bifid.grid[row[i]][row[i+1]]
func decrypt(bifid: Bifid; text: string): string =
## Decrypt "text" using the given cipher.
var row: seq[int]
for ch in text:
let coords = bifid.coords[ch]
row.add [coords[0], coords[1]]
let m = row.len shr 1
let row1 = row[0..<m]
let row2 = row[m..^1]
for i in 0..<m:
result.add bifid.grid[row1[i]][row2[i]]
func `$`(bifid: Bifid): string =
## Display the Polybius square of a Bifid cipher.
result = " " & toSeq(1..bifid.N).join(" ") & '\n'
for row in 1..bifid.N:
result.add alignLeft($row, 2) & bifid.grid[row].join(" ") & '\n'
proc runTest(bifid: Bifid; message: string) =
## Run the test with given cipher and message.
echo "Using Polybius square:"
echo bifid
echo "Message: ", message
let encrypted = bifid.encrypt(message)
echo "Encrypted: ", encrypted
let decrypted = bifid.decrypt(encrypted)
echo "Decrypted: ", decrypted
echo("\n─────────────────────────")
const
Message1 = "ATTACKATDAWN"
Message2 = "FLEEATONCE"
Message3 = "The invasion will start on the first of January".toUpperAscii.replace(" ")
# Using 5x5 Polybius squares.
const
Bifid1 = initBifid(5, "ABCDEFGHIKLMNOPQRSTUVWXYZ")
Bifid2 = initBifid(5, "BGWKZQPNDSIOAXEFCLUMTHYVR")
for (bifid, message) in [(Bifid1, Message1), (Bifid2, Message2),
(Bifid2, Message1), (Bifid1, Message3)]:
runTest(bifid, message)
# Using a 6x6 Polybius square with 26 letters and 10 digits.
const Bifid3 = initBifid(6, "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789")
runTest(Bifid3, Message3)
- Output:
Using Polybius square: 1 2 3 4 5 1 A B C D E 2 F G H I K 3 L M N O P 4 Q R S T U 5 V W X Y Z Message: ATTACKATDAWN Encrypted: DQBDAXDQPDQH Decrypted: ATTACKATDAWN ───────────────────────── Using Polybius square: 1 2 3 4 5 1 B G W K Z 2 Q P N D S 3 I O A X E 4 F C L U M 5 T H Y V R Message: FLEEATONCE Encrypted: UAEOLWRINS Decrypted: FLEEATONCE ───────────────────────── Using Polybius square: 1 2 3 4 5 1 B G W K Z 2 Q P N D S 3 I O A X E 4 F C L U M 5 T H Y V R Message: ATTACKATDAWN Encrypted: EYFENGIWDILA Decrypted: ATTACKATDAWN ───────────────────────── Using Polybius square: 1 2 3 4 5 1 A B C D E 2 F G H I K 3 L M N O P 4 Q R S T U 5 V W X Y Z Message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY Encrypted: RBPDHPHOQTNRBITMFODYPSAOSIAOBTOPDHTDCVI Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY ───────────────────────── Using Polybius square: 1 2 3 4 5 6 1 A B C D E F 2 G H I J K L 3 M N O P Q R 4 S T U V W X 5 Y Z 0 1 2 3 6 4 5 6 7 8 9 Message: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY Encrypted: TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4 Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY ─────────────────────────
PascalABC.NET
// Bifid cipher. Nigel Galloway: September 18th., 2024
function polybius(alphabet:string;n,g:integer):(Dictionary<char,(integer,integer)>,Dictionary<(integer,integer),char>);
begin
var ng:=Cartesian(1..n,1..g);
Result:=(Dict(Zip(alphabet,ng)),Dict(Zip(ng,alphabet)));
end;
function fN(e:Dictionary<char,(integer,integer)>;n:string):(sequence of integer,sequence of integer):=(n.Substring(1).Scan(e[n[1]],(n,g)->e[g])).UnZipTuple;
function encrypt(e:(Dictionary<char,(integer,integer)>,Dictionary<(integer,integer),char>);text:string):string;
begin
var fG:((sequence of integer,sequence of integer),Dictionary<(integer,integer),char>)->string:=(n,e)->(n[0]+n[1]).Batch(2).Aggregate('',(n,g)->n+e[(g[0],g[1])]);
Result:=fG(fN(e[0],text),e[1]);
end;
function decrypt(e:(Dictionary<char,(integer,integer)>,Dictionary<(integer,integer),char>);text:string):string;
begin
var fG:(sequence of (integer,integer),Dictionary<(integer,integer),char>)->string:=(n,e)->n.Aggregate('',(n,g)->n+e[(g[0],g[1])]);
var t:=fN(e[0],text); var z:=t[0].Interleave(t[1]).SplitAt(t[0].count);
Result:=fG(z[0].ZipTuple(z[1]),e[1]);
end;
begin
var p:=polybius('abcdefghiklmnopqrstuvwxyz',5,5); var s,e:string;
s:='fleeatonce'; e:=encrypt(p,s); println($'{s} -> {e} -> {decrypt(p,e)}');
s:='attackatdawn'; e:=encrypt(p,s); println($'{s} -> {e} -> {decrypt(p,e)}');
p:=polybius('bgwkzqpndsioaxefclumthyvr',5,5);
e:=encrypt(p,s); println($'{s} -> {e} -> {decrypt(p,e)}');
s:='fleeatonce'; e:=encrypt(p,s); println($'{s} -> {e} -> {decrypt(p,e)}');
p:=polybius('abcdefghijklmnopqrstuvwxyz0123456789',6,6);
s:='theinvasionwillstarton1january2025'; e:=encrypt(p,s); println($'{s} -> {e} -> {decrypt(p,e)}');
end.
- Output:
fleeatonce -> hadnaazdsp -> fleeatonce attackatdawn -> dqbdaxdqpdqh -> attackatdawn attackatdawn -> eyfengiwdila -> attackatdawn fleeatonce -> uaeolwrins -> fleeatonce theinvasionwillstarton1january2025 -> tbpdiphjspozcsq23h0jaokr4g5nvbm40z -> theinvasionwillstarton1january2025
Perl
use v5.36;
use builtin <indexed floor>;
use experimental qw(builtin for_list);
use List::Util 'max';
sub table ($c, @V) { my $t = $c * (my $w = 2 + length max map { length } @V); ( sprintf( ('%'.$w.'s')x@V, @V) ) =~ s/.{1,$t}\K/\n/gr }
sub polybius ($text) {
my %p;
my $n = floor sqrt length $text;
for my($k,$v) (indexed split '', $text) {
$p{$v} = join ' ', $k%$n, int $k/$n
}
%p;
}
sub encrypt ($text, %P) {
my(%I, @c, $encrypted);
for my($k,$v) (%P) { $I{$v} = $k }
for my ($n,$char) (indexed split '', ($text =~ s/\s//gr)) {
for my($m,$i) (indexed split ' ', $P{$char}) { $c[$m][$n] = $i }
}
for my($i,$j) ($c[1]->@*, $c[0]->@*) { $encrypted .= $I{"$j $i"} }
$encrypted
}
sub decrypt ($text, %P) {
my($decrypted, $l, %I, @c) = ('', length($text));
for my($k,$v) (%P) { $I{$v} = $k }
for (split '', $text) {
for my($i,$j) (split ' ', $P{$_}) { unshift @c, $i, $j }
}
substr $decrypted, 0, 0, $I{ "$c[$_] $c[$_+$l]" } for 0 .. $l-1;
$decrypted;
}
for my($polybius,$message) (
join('','A'..'Z') =~ s/J//r, 'ATTACK AT DAWN',
'BGWKZQPNDSIOAXEFCLUMTHYVR', 'FLEE AT ONCE',
join('','_.', 'A'..'Z', 'a'..'z', '0'..'9'), 'The_invasion_will_start_on_the_first_of_January_2023.',
) {
my %Ptable = polybius $polybius;
say "\nUsing polybius:\n" . table sqrt length $polybius, split '', $polybius;
say 'Message : ' . $message;
say 'Encrypted : ' . (my $encrypted = encrypt $message, %Ptable);
say 'Decrypted : ' . decrypt $encrypted, %Ptable;
}
- Output:
Using polybius: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message : ATTACK AT DAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN Using polybius: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message : FLEE AT ONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE Using polybius: _ . A B C D E F G H I J K L M N O P Q R S T U V W X Y Z a b c d e f g h i j k l m n o p q r s t u v w x y z 0 1 2 3 4 5 6 7 8 9 Message : The_invasion_will_start_on_the_first_of_January_2023. Encrypted : SejxqrEierbmrDiCjrDeJsbu89DWCHkgGS9E6tAG5_Ks2PBfCq_uH Decrypted : The_invasion_will_start_on_the_first_of_January_2023.
Phix
with javascript_semantics enum encrypt,decrypt function bifid(string msg, polybius, sequence p, integer n, ed) string res = "" sequence dx = {}, dy = {}, dxy for i=1 to length(msg) do integer k = find(msg[i],polybius)-1 dx &= floor(k/n)+1 dy &= remainder(k,n)+1 end for if ed=encrypt then dxy = split_by(dx&dy,2) else -- "simply reversing these steps" - yeah, right... dxy = columnize(split_by(flatten(columnize({dx,dy})),length(dx))) end if for i=1 to length(dxy) do integer {x,y} = dxy[i] res &= p[x][y] end for return res end function procedure test(string msg, polybius) integer n = sqrt(length(polybius)) if n=5 then msg = substitute(upper(msg),"J","I") end if sequence p = split_by(polybius,n) string enc = bifid(msg,polybius,p,n,encrypt), dec = bifid(enc,polybius,p,n,decrypt) printf(1,"For %dx%d polybius %s\n\n",{n,n,join(p,"\n ")}) printf(1,"Message : %s\nEncrypted: %s\nDecrypted: %s\n\n",{msg,enc,dec}) end procedure constant polybii = {tagstart('A','J'-'A')&tagstart('K','Z'-'J'), "BGWKZQPNDSIOAXEFCLUMTHYVR", " ."&tagstart('A',26)&tagstart('a',26)&tagstart('0',10)}, messages = {"ATTACKATDAWN","FLEEATONCE", "The invasion will start on the first of January 2023."} for t=1 to 3 do test(messages[t],polybii[t]) end for
- Output:
For 5x5 polybius ABCDE
FGHIK
LMNOP
QRSTU
VWXYZ
Message : ATTACKATDAWN
Encrypted: DQBDAXDQPDQH
Decrypted: ATTACKATDAWN
For 5x5 polybius BGWKZ
QPNDS
IOAXE
FCLUM
THYVR
Message : FLEEATONCE
Encrypted: UAEOLWRINS
Decrypted: FLEEATONCE
For 8x8 polybius .ABCDEF
GHIJKLMN
OPQRSTUV
WXYZabcd
efghijkl
mnopqrst
uvwxyz01
23456789
Message : The invasion will start on the first of January 2023.
Encrypted: SejxqrEierbmrDiCjrDeJsbu89DWCHkgGS9E6tAG5 Ks2PBfCq uH
Decrypted: The invasion will start on the first of January 2023.
Python
"""Bifid cipher. Requires Python >=3.7."""
import math
import pprint
import string
from itertools import chain
from itertools import zip_longest
from typing import Dict
from typing import Iterable
from typing import Iterator
from typing import Tuple
from typing import TypeVar
T = TypeVar("T")
def group(it: Iterable[T], n: int) -> Iterator[Tuple[T, ...]]:
"""Return the input iterable split in to `n` equal chunks, padded with `None`."""
return zip_longest(*[iter(it)] * n)
Square = Tuple[Tuple[str, ...], ...]
def polybius_square(alphabet: str) -> Square:
"""Return the given alphabet as a tuple of tuples, representing a Polybius square."""
return tuple(group(alphabet, math.ceil(math.sqrt(len(alphabet)))))
def polybius_map(square: Square) -> Dict[str, Tuple[int, int]]:
"""Return a reverse lookup for the given Polybius square."""
return {
square[i][j]: (i + 1, j + 1)
for i in range(len(square))
for j in range(len(square))
}
def encrypt(message: str, square: Square) -> str:
"""Encrypt a plaintext message using a bifid cipher with the given Polybius square."""
_map = polybius_map(square)
return "".join(
square[x - 1][y - 1]
for x, y in group(
chain.from_iterable(zip(*(_map[c] for c in message if c in _map))),
2,
)
)
def decrypt(message: str, square: Square) -> str:
"""Decrypt a ciphertext message using a bifid cipher with the given Polybius square."""
_map = polybius_map(square)
return "".join(
square[x - 1][y - 1]
for x, y in zip(
*group(
chain.from_iterable((_map[c] for c in message if c in _map)),
len(message),
)
)
)
def normalize(message: str) -> str:
"""Normalize a message for the typical Polybius square."""
return message.upper().replace("J", "I")
TYPICAL_POLYBIUS_SQUARE = polybius_square(
alphabet="".join(c for c in string.ascii_uppercase if c != "J")
)
EXAMPLE_POLYBIUS_SQUARE = polybius_square(
alphabet="BGWKZQPNDSIOAXEFCLUMTHYVR",
)
def main() -> None:
test_cases = [
("ATTACKATDAWN", TYPICAL_POLYBIUS_SQUARE), # 1
("FLEEATONCE", EXAMPLE_POLYBIUS_SQUARE), # 2
("FLEEATONCE", TYPICAL_POLYBIUS_SQUARE), # 3
(
normalize("The invasion will start on the first of January"),
polybius_square(alphabet="PLAYFIREXMBCDGHKNOQSTUVWZ"),
),
(
"The invasion will start on the first of January".upper(),
polybius_square(alphabet=string.ascii_uppercase + string.digits),
),
]
for message, square in test_cases:
pprint.pprint(square)
print("Message :", message)
print("Encrypted:", encrypt(message, square))
print("Decrypted:", decrypt(encrypt(message, square), square))
print("")
if __name__ == "__main__":
main()
- Output:
(('A', 'B', 'C', 'D', 'E'),
('F', 'G', 'H', 'I', 'K'),
('L', 'M', 'N', 'O', 'P'),
('Q', 'R', 'S', 'T', 'U'),
('V', 'W', 'X', 'Y', 'Z'))
Message : ATTACKATDAWN
Encrypted: DQBDAXDQPDQH
Decrypted: ATTACKATDAWN
(('B', 'G', 'W', 'K', 'Z'),
('Q', 'P', 'N', 'D', 'S'),
('I', 'O', 'A', 'X', 'E'),
('F', 'C', 'L', 'U', 'M'),
('T', 'H', 'Y', 'V', 'R'))
Message : FLEEATONCE
Encrypted: UAEOLWRINS
Decrypted: FLEEATONCE
(('A', 'B', 'C', 'D', 'E'),
('F', 'G', 'H', 'I', 'K'),
('L', 'M', 'N', 'O', 'P'),
('Q', 'R', 'S', 'T', 'U'),
('V', 'W', 'X', 'Y', 'Z'))
Message : FLEEATONCE
Encrypted: HADNAAZDSP
Decrypted: FLEEATONCE
(('P', 'L', 'A', 'Y', 'F'),
('I', 'R', 'E', 'X', 'M'),
('B', 'C', 'D', 'G', 'H'),
('K', 'N', 'O', 'Q', 'S'),
('T', 'U', 'V', 'W', 'Z'))
Message : THE INVASION WILL START ON THE FIRST OF IANUARY
Encrypted: VRSYXSIYTMQVIRSKISLPVLDTCKRTCAIVTMATCEX
Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
(('A', 'B', 'C', 'D', 'E', 'F'),
('G', 'H', 'I', 'J', 'K', 'L'),
('M', 'N', 'O', 'P', 'Q', 'R'),
('S', 'T', 'U', 'V', 'W', 'X'),
('Y', 'Z', '0', '1', '2', '3'),
('4', '5', '6', '7', '8', '9'))
Message : THE INVASION WILL START ON THE FIRST OF JANUARY
Encrypted: TBPDIPHJSPOTAIVMGPCZKNSCN09BFIHK64I7BM4
Decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFJANUARY
Quackery
transpose is defined at Matrix transposition#Quackery.
[ $ "" swap
witheach
[ upper
dup char I > if [ 1 - ]
dup char A char Z
within iff
[ char A - join ]
else drop ] ] is ->0..24 ( $ --> [ )
[ $ "" swap
witheach
[ char A +
dup char I > if 1+
join ] ] is ->A..Z ( [ --> $ )
[ [] 5 times
[ dip ->0..24 join ] ] is makesquare ( $ $ $ $ $ --> [ )
[ dup witheach
[ i^ unrot poke ] ] is makeindex ( [ --> [ )
[ dup temp put
makeindex temp put
->0..24
[] swap witheach
[ temp share swap peek
5 /mod join
nested join ]
temp release
transpose
unpack join
[] swap
dup size 2 / times
[ 2 split dip
[ nested join ] ]
drop
$ "" swap
witheach
[ unpack swap 5 * +
temp share swap peek
join ]
->A..Z
temp release ] is encrypt ( $ [ --> $ )
[ dup temp put
makeindex temp put
->0..24
[] swap witheach
[ temp share swap peek
5 /mod join join ]
temp release
dup size 2 / split
2 pack
transpose
[] swap witheach
[ unpack swap 5 * +
temp share swap peek
join ]
->A..Z
temp release ] is decrypt ( $ [ --> $ )
[ $ "ABCDE"
$ "FGHIK"
$ "LMNOP"
$ "QRSTU"
$ "VWXYZ"
makesquare ] constant is tasksquare ( --> [ )
[ $ "BGWKZ"
$ "QPNDS"
$ "IOAXE"
$ "FCLUM"
$ "THYVR"
makesquare ] constant is wikisquare ( --> [ )
[ $ "QUACK"
$ "DEPTH"
$ "LYING"
$ "FORMS"
$ "BVWXZ"
makesquare ] constant is ducksquare ( --> [ )
say "Using tasksquare:" cr
$ "Attack at dawn." dup echo$ say " -> "
tasksquare encrypt dup echo$ say " -> "
tasksquare decrypt echo$
cr cr
say "Using wikisquare:" cr
$ "Flee at once." dup echo$ say " -> "
wikisquare encrypt dup echo$ say " -> "
wikisquare decrypt echo$
cr cr
say "Using ducksquare:" cr
$ "The invasion will start on the first of January." dup echo$ cr say " -> "
ducksquare encrypt dup echo$ cr say " -> "
ducksquare decrypt echo$- Output:
Using tasksquare: Attack at dawn. -> DQBDAXDQPDQH -> ATTACKATDAWN Using wikisquare: Flee at once. -> UAEOLWRINS -> FLEEATONCE Using ducksquare: The invasion will start on the first of January. -> EPGCNGINDORETNOMLLCNVNPWTIQXIOMVAGOANPY -> THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
Raku
Technically incorrect as the third part doesn't "Convert ... to upper case and ignore spaces".
sub polybius ($text) {
my $n = $text.chars.sqrt.narrow;
$text.comb.kv.map: { $^v => ($^k % $n, $k div $n).join: ' ' }
}
sub encrypt ($message, %poly) {
%poly.invert.hash{(flat reverse [Z] %poly{$message.comb}».words).batch(2)».reverse».join: ' '}.join
}
sub decrypt ($message, %poly) {
%poly.invert.hash{reverse [Z] (reverse flat %poly{$message.comb}».words».reverse).batch($message.chars)}.join
}
for 'ABCDEFGHIKLMNOPQRSTUVWXYZ', 'ATTACKATDAWN',
'BGWKZQPNDSIOAXEFCLUMTHYVR', 'FLEEATONCE',
(flat '_', '.', 'A'..'Z', 'a'..'z', 0..9).pick(*).join, 'The invasion will start on the first of January 2023.'.subst(/' '/, '_', :g)
-> $polybius, $message {
my %polybius = polybius $polybius;
say "\nUsing polybius:\n\t" ~ $polybius.comb.batch($polybius.chars.sqrt.narrow).join: "\n\t";
say "\n Message : $message";
say "Encrypted : " ~ my $encrypted = encrypt $message, %polybius;
say "Decrypted : " ~ decrypt $encrypted, %polybius;
}
- Output:
Using polybius: A B C D E F G H I K L M N O P Q R S T U V W X Y Z Message : ATTACKATDAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN Using polybius: B G W K Z Q P N D S I O A X E F C L U M T H Y V R Message : FLEEATONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE Using polybius: H c F T N 5 f i _ U k R B Z V W 3 G e v s w j x q S 2 8 y Q . O m 0 E d h D r u M p 7 Y 4 A 9 a t X l I 6 g b z J P n 1 K L C o Message : The_invasion_will_start_on_the_first_of_January_2023. Encrypted : NGiw3okfXj4XoVE_NjWcLK4Sy28EivKo3aeNiti3N3z6HCHno6Fkf Decrypted : The_invasion_will_start_on_the_first_of_January_2023.
RPL
« DUP SIZE √ "" → in key n out
« { } DUP
1 in SIZE FOR j
key in j DUP SUB
POS 1 - n MOD LASTARG / IP
SWAP ROT SWAP + ROT ROT + SWAP
NEXT
+ 'in' STO
1 in SIZE FOR j
'out' key
in j DUP 1 + SUB
OBJ→ DROP SWAP n * + 1 +
DUP SUB STO+
2 STEP
out
» » '→BIFCOD' STO
« DUP SIZE √ "" → in key n out
« { }
1 in SIZE FOR j
key in j DUP SUB POS
1 - n MOD LASTARG / IP
ROT SWAP + SWAP +
NEXT
DUP 'in' STO SIZE 2 /
1 OVER FOR j
'out' key
in j GET n * in 5 PICK j + GET + 1 +
DUP SUB STO+
NEXT
DROP out
» » '→BIFDEC' STO
« { "ATTACKATDAWN" "ABCDEFGHIKLMNOPQRSTUVWXYZ"
"FLEEATONCE" "BGWKZQPNDSIOAXEFCLUMTHYVR"
"ATTACKATDAWN" "BGWKZQPNDSIOAXEFCLUMTHYVR"
"THE INVASION WILL START ON THE FIRST OF JANUARY" "ABCDEFGHIJKLMNOPQRSTUVWXYZ 123456789" }
→ examples
« 1 examples SIZE FOR j
examples j GETI ROT ROT GET
→BIFCOD DUP examples j 1 + GET
→BIFDEC 2 →LIST
2 STEP
» » 'TASK' STO
- Output:
4: { "DQBDAXDQPDQH" "ATTACKATDAWN" }
3: { "UAEOLWRINS" "FLEEATONCE" }
2: { "EYFENGIWDILA" "ATTACKATDAWN" }
1: { "TEISTO1HKVCWO1GYIV EGPCZKOJAOI 9MG5OIH 64IRPBM4" "THE INVASION WILL START ON THE FIRST OF JANUARY" }
Ruby
def cleanMsg(msg, square)
msg.upcase!
msg.delete!(' ')
msg.delete!('J') if square.index('J') == nil
end
def encrypt(msg, square)
cleanMsg msg, square
sq_size = (square.length ** 0.5).to_i
rows = [0] * msg.length
cols = [0] * msg.length
(0...msg.length).each do |i|
p = square.index(msg[i])
rows[i], cols[i] = p / sq_size, p % sq_size
end
result = ""
rows.concat(cols).each_slice(2) do |coord|
result += square[coord[0]*sq_size + coord[1]]
end
return result
end
def decrypt(msg, square)
msg.upcase!; square.upcase!
sq_size = (square.length ** 0.5).to_i
coords = []
result = ""
(0...msg.length).each do |i|
p = square.index(msg[i])
coords << p / sq_size
coords << p % sq_size
end
for i in (0...coords.length/2) do
row, col = coords[i], coords[i+coords.length/2]
result += square[row*sq_size + col]
end
return result
end
def printSquare(square)
sq_size = (square.length ** 0.5).to_i
(0..square.length).step(sq_size).each do |i|
print square[i...(i+sq_size)], "\n"
end
end
tests = [["ATTACKATDAWN" , "ABCDEFGHIKLMNOPQRSTUVWXYZ"],
["FLEEATONCE" , "BGWKZQPNDSIOAXEFCLUMTHYVR"],
["ATTACKATDAWN" , "ABCDEFGHIKLMNOPQRSTUVWXYZ"],
["the invasion will start on the first of january", "BGWKZQPNDSIOAXEFCLUMTHYVR"],
["THIS MESSAGE HAS NUMBERS 2023", "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890"],
]
for test in tests
message = test[0]; square = test[1];
encrypted = encrypt(message, square)
decrypted = decrypt(encrypted, square)
puts "using the polybius:"
printSquare(square)
puts "the plain message:", message
puts "encrypted:", encrypted
puts "decrypted:", decrypted
puts "===================================================="
end
- Output:
using the polybius: ABCDE FGHIK LMNOP QRSTU VWXYZ the plain message: ATTACKATDAWN encrypted: DQBDAXDQPDQH decrypted: ATTACKATDAWN ==================================================== using the polybius: BGWKZ QPNDS IOAXE FCLUM THYVR the plain message: FLEEATONCE encrypted: UAEOLWRINS decrypted: FLEEATONCE ==================================================== using the polybius: ABCDE FGHIK LMNOP QRSTU VWXYZ the plain message: ATTACKATDAWN encrypted: DQBDAXDQPDQH decrypted: ATTACKATDAWN ==================================================== using the polybius: BGWKZ QPNDS IOAXE FCLUM THYVR the plain message: THEINVASIONWILLSTARTONTHEFIRSTOFANUARY encrypted: RASOAQXCYRORXESXOLRGTXEGAWEWTNGTZTQALY decrypted: THEINVASIONWILLSTARTONTHEFIRSTOFANUARY ==================================================== using the polybius: ABCDEF GHIJKL MNOPQR STUVWX YZ1234 567890 the plain message: THISMESSAGEHASNUMBERS2023 encrypted: TJMVBBDPMCW9ZIAYAEGBMK5XW decrypted: THISMESSAGEHASNUMBERS2023 ====================================================
Uiua
Standard
The following just uses the standard version of the cipher.
S ← "ABCDEFGHIKLMNOPQRSTUVWXYZ"
P ← ↯⊟.√⧻.S
Prep ← ▽∊:S.∧⍜⊡⋅@I⊚⌕@J.⌵
Bifid ← setinv(
⊡:⟜(↯∞_2/⊂⇌⍉≡(⊢⊚⌕)Prep:¤)P
| ⊡:⟜(⍉⇌↯2_∞/⊂≡(⊢⊚⌕):¤)P
)
°Bifid.Bifid. "This is it"
°Bifid.Bifid. "The invasion will start on the first of January"- Output:
"This is it" "SSSTRIII" "THISISIT" "The invasion will start on the first of January" "SYLCTMQCQISSVROQQPBTFHVRNWNTDSOFGTSGCQU" "THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY"
Extended
26 letters and 10 digits = 36 chars, so that's the obvious extension. Plus super-security is guaranteed by adding the use of a codeword in the grid :-)
S ← "GLYPHABCDEFIJKMNOQRSTUVWXZ0123456789"
P ← ↯⊟.√⧻.S
Prep ← ▽∊:S.⌵
Bifid ← setinv(
⊡:⟜(↯∞_2/⊂⇌⍉≡(⊢⊚⌕)Prep:¤)P
| ⊡:⟜(⍉⇌↯2_∞/⊂≡(⊢⊚⌕):¤)P
)
°Bifid.Bifid. "This is it"
°Bifid.Bifid. "The invasion will start at 0600 on the 1st of January"- Output:
"This is it" "O556REEE" "THISISIT" "The invasion will start at 0600 on the 1st of January" "OWV58W5CQY6MM1OUD2AU4NLDRSMSGUPRV80NL1TDYRR" "THEINVASIONWILLSTARTAT0600ONTHE1STOFJANUARY"
Wren
One way of enabling all 26 letters to be encrypted uniquely would be to use a 6 x 6 Polybius square including the 10 digits. We could then encrypt text using numerals as well.
However, the following just uses the standard version of the cipher.
import "./str" for Str
import "./seq" for Lst
class Bifid {
static encrypt(polybius, message) {
message = Str.upper(message).replace("J", "I")
var rows = []
var cols = []
for (c in message) {
var ix = polybius.indexOf(c)
if (ix == -1) continue
rows.add((ix/5).floor + 1)
cols.add((ix%5) + 1)
}
var s = ""
for (pair in Lst.chunks(rows + cols, 2)) {
var ix = (pair[0] - 1) * 5 + pair[1] - 1
s = s + polybius[ix]
}
return s
}
static decrypt(polybius, message) {
var rows = []
var cols = []
for (c in message) {
var ix = polybius.indexOf(c)
rows.add((ix/5).floor + 1)
cols.add((ix%5) + 1)
}
var lines = Lst.flatten(Lst.zip(rows, cols))
var count = lines.count/2
rows = lines[0...count]
cols = lines[count..-1]
var s = ""
for (i in 0...count) {
var ix = (rows[i] - 1) * 5 + cols[i] - 1
s = s + polybius[ix]
}
return s
}
}
var poly1 = "ABCDEFGHIKLMNOPQRSTUVWXYZ"
var poly2 = "BGWKZQPNDSIOAXEFCLUMTHYVR"
var poly3 = "PLAYFIREXMBCDGHKNOQSTUVWZ"
var polys = [poly1, poly2, poly2, poly3]
var msg1 = "ATTACKATDAWN"
var msg2 = "FLEEATONCE"
var msg3 = "The invasion will start on the first of January"
var msgs = [msg1, msg2, msg1, msg3]
for (i in 0...msgs.count) {
var encrypted = Bifid.encrypt(polys[i], msgs[i])
var decrypted = Bifid.decrypt(polys[i], encrypted)
System.print("Message : %(msgs[i])")
System.print("Encrypted : %(encrypted)")
System.print("Decrypted : %(decrypted)")
if (i < msgs.count-1) System.print()
}
- Output:
Message : ATTACKATDAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN Message : FLEEATONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE Message : ATTACKATDAWN Encrypted : EYFENGIWDILA Decrypted : ATTACKATDAWN Message : The invasion will start on the first of January Encrypted : VRSYXSIYTMQVIRSKISLPVLDTCKRTCAIVTMATCEX Decrypted : THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY
XPL0
string 0; \use zero-terminated strings
def MaxLen = 100; \more than length of longest message
func StrLen(A); \Return number of characters in an ASCIIZ string
char A;
int I;
for I:= 0 to MaxLen do
if A(I) = 0 then return I;
proc StrUpper(S); \In string S, convert lowercase characters to uppercase
char S;
int I;
for I:= 0 to StrLen(S)-1 do
if S(I)>=^a & S(I)<=^z then S(I):= S(I) & $DF;
proc StrReplace(S, C1, C2); \In string S, convert character C1 to C2
char S, C1, C2;
int I;
for I:= 0 to StrLen(S)-1 do
if S(I) = C1 then S(I):= C2;
func IndexOf(S, C); \Return offset of character C in string S
char S, C;
int I;
[for I:= 0 to StrLen(S)-1 do
if S(I) = C then return I;
return -1;
];
char Encrypted(MaxLen), Decrypted(MaxLen);
proc Encrypt(Polybius, Message); \Copy encrypted Message into Encrypted
char Polybius, Message;
char Rows(MaxLen*2), Cols(MaxLen);
int C, IX, I, J, Len;
[Len:= StrLen(Message);
for I:= 0 to Len do \copy Message into Encrypted
Encrypted(I):= Message(I);
StrUpper(Encrypted);
StrReplace(Encrypted, ^J, ^I);
I:= 0; J:= 0;
loop [C:= Encrypted(I);
I:= I+1;
if C = 0 then quit;
IX:= IndexOf(Polybius, C);
if IX >= 0 then \ignores spaces, etc.
[Rows(J):= IX/5;
Cols(J):= rem(0);
J:= J+1;
];
];
Len:= J; \length of encrypted message
for I:= 0 to Len-1 do \append Cols onto end of Rows
Rows(I+Len):= Cols(I);
for I:= 0 to Len-1 do
[IX:= Rows(I*2)*5 + Rows(I*2+1);
Encrypted(I):= Polybius(IX);
];
Encrypted(I):= 0; \terminate string
];
proc Decrypt(Polybius, Message); \Copy decrypted Message into Decrypted
char Polybius, Message;
char Rows(MaxLen*2), Cols(MaxLen);
int C, IX, I, J, Len;
[I:= 0; J:= 0;
loop [C:= Message(I);
if C = 0 then quit;
I:= I+1;
IX:= IndexOf(Polybius, C);
Rows(J):= IX/5;
Rows(J+1):= rem(0);
J:= J+2;
];
Len:= I;
Cols:= Rows + Len;
for I:= 0 to Len-1 do
[IX:= Rows(I)*5 + Cols(I);
Decrypted(I):= Polybius(IX);
];
Decrypted(I):= 0;
];
int Polys, Msgs, I;
[Polys:= ["ABCDEFGHIKLMNOPQRSTUVWXYZ",
"BGWKZQPNDSIOAXEFCLUMTHYVR",
"BGWKZQPNDSIOAXEFCLUMTHYVR",
"PLAYFIREXMBCDGHKNOQSTUVWZ"];
Msgs:= ["ATTACKATDAWN",
"FLEEATONCE",
"ATTACKATDAWN",
"The invasion will start on the first of January"];
for I:= 0 to 4-1 do
[Encrypt(Polys(I), Msgs(I));
Decrypt(Polys(I), Encrypted);
Text(0, "Message : "); Text(0, Msgs(I)); CrLf(0);
Text(0, "Encrypted : "); Text(0, Encrypted); CrLf(0);
Text(0, "Decrypted : "); Text(0, Decrypted); CrLf(0);
if I < 4-1 then CrLf(0);
];
]- Output:
Message : ATTACKATDAWN Encrypted : DQBDAXDQPDQH Decrypted : ATTACKATDAWN Message : FLEEATONCE Encrypted : UAEOLWRINS Decrypted : FLEEATONCE Message : ATTACKATDAWN Encrypted : EYFENGIWDILA Decrypted : ATTACKATDAWN Message : The invasion will start on the first of January Encrypted : VRSYXSIYTMQVIRSKISLPVLDTCKRTCAIVTMATCEX Decrypted : THEINVASIONWILLSTARTONTHEFIRSTOFIANUARY