Bacon cipher
Bacon's cipher is a method of steganography created by Francis Bacon. This task is to implement a program for encryption and decryption of plaintext using the simple alphabet of the Baconian cipher or some other kind of representation of this alphabet (make anything signify anything).
The Baconian alphabet:
a AAAAA g AABBA n ABBAA t BAABA b AAAAB h AABBB o ABBAB u-v BAABB c AAABA i-j ABAAA p ABBBA w BABAA d AAABB k ABAAB q ABBBB x BABAB e AABAA l ABABA r BAAAA y BABBA f AABAB m ABABB s BAAAB z BABBB
C++
Bacon cipher implementation
<lang cpp>
- include <iostream>
- include <algorithm>
- include <vector>
- include <bitset>
- include <string>
class bacon { public:
bacon() {
int x = 0;
for( ; x < 9; x++ )
bAlphabet.push_back( std::bitset<5>( x ).to_string() );
bAlphabet.push_back( bAlphabet.back() );
for( ; x < 20; x++ )
bAlphabet.push_back( std::bitset<5>( x ).to_string() );
bAlphabet.push_back( bAlphabet.back() );
for( ; x < 24; x++ )
bAlphabet.push_back( std::bitset<5>( x ).to_string() );
}
std::string encode( std::string txt ) {
std::string r;
size_t z;
for( std::string::iterator i = txt.begin(); i != txt.end(); i++ ) {
z = toupper( *i );
if( z < 'A' || z > 'Z' ) continue;
r.append( bAlphabet.at( ( *i & 31 ) - 1 ) );
}
return r;
}
std::string decode( std::string txt ) {
size_t len = txt.length();
while( len % 5 != 0 ) len--;
if( len != txt.length() ) txt = txt.substr( 0, len );
std::string r;
for( size_t i = 0; i < len; i += 5 ) {
r.append( 1, 'A' + std::distance( bAlphabet.begin(), std::find( bAlphabet.begin(), bAlphabet.end(), txt.substr( i, 5 ) ) ) );
}
return r;
}
private:
std::vector<std::string> bAlphabet;
}; </lang>
These next 2 classes use the 0's & 1's generated by the 'Bacon encryption' to create different the outputs. One could go wild here... <lang cpp> class cipherI { public:
std::string encode( std::string txt ) {
txt = b.encode( txt );
std::string e, d = "one morning, when gregor samsa woke from troubled dreams, he found himself transformed "
"in his bed into a horrible vermin. he lay on his armour-like back, and if he lifted his head a little he "
"could see his brown belly, slightly domed and divided by arches into stiff sections.";
size_t r = 0;
char t;
for( std::string::iterator i = txt.begin(); i != txt.end(); i++ ) {
t = d.at( r );
while( t < 'a' || t > 'z' ) {
e.append( 1, t );
r++;
t = d.at( r );
}
r++;
e.append( 1, *i == '1' ? t - 32 : t );
}
return e; }
std::string decode( std::string txt ) {
std::string h;
for( std::string::iterator i = txt.begin(); i != txt.end(); i++ ) {
if( *i < 'a' && ( *i < 'A' || *i > 'Z' ) || *i > 'z' ) continue;
h.append( 1, *i & 32 ? '0' : '1' );
}
return b.decode( h );
}
private:
bacon b;
};
class cipherII { public:
std::string encode( std::string txt ) {
txt = b.encode( txt );
std::string e;
for( std::string::iterator i = txt.begin(); i != txt.end(); i++ )
e.append( 1, *i == '0' ? 0xf9 : 0xfa );
return e;
}
std::string decode( std::string txt ) {
std::string h;
for( std::string::iterator i = txt.begin(); i != txt.end(); i++ ) {
h.append( 1, *i == ( char )0xf9 ? '0' : '1' );
}
return b.decode( h );
}
private:
bacon b;
};
int main( int argc, char* argv[] ) {
cipherI c1; cipherII c2; std::string s = "lets have some fun with bacon cipher";
std::string h1 = c1.encode( s ),
h2 = c2.encode( s );
std::cout << h1 << std::endl << std::endl << c1.decode( h1 ) << std::endl << std::endl; std::cout << h2 << std::endl << std::endl << c2.decode( h2 ) << std::endl << std::endl;
return 0;
} </lang>
- Output:
oNe MornIng, WheN gRegoR saMSA woke fRom TRouBleD dreAmS, He FoUnD HimSelf tRaNS foRMeD In hIs Bed iNto a HorRiblE VErmin. He lay on hiS arMOuR-lIKe back, And If he lIFTed hIS HeaD a lIttle LETSHAUESOMEFUNWITHBACONCIPHER ¨·¨·¨¨¨·¨¨·¨¨·¨·¨¨¨·¨¨···¨¨¨¨¨·¨¨··¨¨·¨¨·¨¨¨·¨··¨·¨·¨··¨¨·¨¨¨¨·¨··¨¨··¨··¨¨·¨·¨¨ ¨·¨¨¨·¨¨·¨¨¨···¨¨¨¨·¨¨¨¨¨¨¨¨·¨¨··¨·¨··¨¨¨¨¨·¨¨·¨¨¨¨···¨¨¨···¨¨·¨¨·¨¨¨¨ LETSHAUESOMEFUNWITHBACONCIPHER
J
Implementation:
<lang J>alfa=: 'ABCDEFGHIKLMNOPQRSTUWXYZ' beta=: 26{.(}.~i.&'A')a. norm=: ([ -. -.)&alfa@(rplc&('JIVU'))@toupper enca=:(5#2),@:#:alfa i. norm gena=: ]`((,:tolower)@(beta {~ 26 ?@#~ #))}
encrypt=: gena@enca@norm decrypt=: alfa {~ _5 #.\ 90 < a.&i.</lang>
We use random letters as the basis for our steganography and we use case to represent "font".
Example use:
<lang J> encrypt 'this is a test' nWVkJAPkamEuUJIeTGKnUsTVRfAWWuNBIIHdEIcOAPuTBeXKQduQAdU
encrypt 'this is a test'
sFLkBQKqqaQsGGXzAXQsKlZFBcILRlUIRAQaEQoNUBcHIhFTWbeRAlM
decrypt encrypt 'this is a test'
THISISATEST</lang>
Python
This deviates from the Bacon method as it encodes to different capitalisation of text rather than differences in font.
<lang python>import string
sometext = """All children, except one, grow up. They soon know that they will grow up, and the way Wendy knew was this. One day when she was two years old she was playing in a garden, and she plucked another flower and ran with it to her mother. I suppose she must have looked rather delightful, for Mrs. Darling put her hand to her heart and cried, "Oh, why can't you remain like this for ever!" This was all that passed between them on the subject, but henceforth Wendy knew that she must grow up. You always know after you are two. Two is the beginning of the end.
Of course they lived at 14 [their house number on their street], and until Wendy came her mother was the chief one. She was a lovely lady, with a romantic mind and such a sweet mocking mouth. Her romantic mind was like the tiny boxes, one within the other, that come from the puzzling East, however many you discover there is always one more; and her sweet mocking mouth had one kiss on it that Wendy could never get, though there it was, perfectly conspicuous in the right-hand corner.""".lower()
lc2bin = {ch: '{:05b}'.format(i)
for i, ch in enumerate(string.ascii_lowercase + ' .')}
bin2lc = {val: key for key, val in lc2bin.items()}
phrase = 'Rosetta code Bacon cipher example secret phrase to encode in the capitalisation of peter pan'.lower()
def to_5binary(msg):
return ( ch == '1' for ch in .join(lc2bin.get(ch, ) for ch in msg.lower()))
def encrypt(message, text):
bin5 = to_5binary(message)
textlist = list(text.lower())
out = []
for capitalise in bin5:
while textlist:
ch = textlist.pop(0)
if ch.isalpha():
if capitalise:
ch = ch.upper()
out.append(ch)
break
else:
out.append(ch)
else:
raise Exception('ERROR: Ran out of characters in sometext')
return .join(out) + '...'
def decrypt(bacontext):
binary = []
bin5 = []
out = []
for ch in bacontext:
if ch.isalpha():
binary.append('1' if ch.isupper() else '0')
if len(binary) == 5:
bin5 = .join(binary)
out.append(bin2lc[bin5])
binary = []
return .join(out)
print('PLAINTEXT = \n%s\n' % phrase) encrypted = encrypt(phrase, sometext) print('ENCRYPTED = \n%s\n' % encrypted) decrypted = decrypt(encrypted) print('DECRYPTED = \n%s\n' % decrypted) assert phrase == decrypted, 'Round-tripping error'</lang>
- Output:
PLAINTEXT = rosetta code bacon cipher example secret phrase to encode in the capitalisation of peter pan ENCRYPTED = All cHiLDReN, exCept One, GroW UP. thEY soon kNOw That tHey WILl groW Up, aNd tHE wAy wendY knew was tHis. ONE daY WhEN ShE was tWo yEars oLD SHe wAS PlaYinG in a GARdEn, anD shE pLUCked anoTHer fLOWEr AnD Ran WitH It To Her MothEr. i supPoSe shE muSt hAve LOOKeD raTHER deLIGHtfuL, for mrS. daRlinG puT HeR hAnd TO hER HeARt And cRied, "OH, wHy caN't yOU RemaiN LikE thIS fOr eVer!" thIS wAS AlL tHat PAssED BetWeeN ThEm on tHe subjecT, BUT hEnceForTH wendy kNeW ThAt shE muSt grow uP. yoU AlWays kNOW afTEr YOU aRe tWO. Two iS tHE BeGinNING of The End. OF coUrsE theY LIvEd aT 14 [THEir housE NuM... DECRYPTED = rosetta code bacon cipher example secret phrase to encode in the capitalisation of peter pan
REXX
This REXX version supports a full (26-letter) Roman (Latin) alphabet, plus a few punctuation symbols:
. (period),
, (comma),
? (question mark),
! (exclamation mark), and blanks.
All alphabetic letters are handled as if they were in uppercase (i.e., lowercase letters are uppercased). <lang rexx>/*REXX program implements and demonstrates a (full) "Bacon" cipher (cypher).*/ parse arg plain /*obtain optional arguments from the CL*/ if plain= then plain = "The quick brown fox jumped over the lazy dog."
/* [↓] code supports complete alphabet*/
@.=; @.a=11111; @.b=11110; @.c=11101; @.d=11100; @.e=11011; @.f=11010
@.g=11001; @.h=11000; @.i=10111; @.j=00111; @.k=10110; @.l=10101; @.m=10100
@.n=10011; @.o=10010; @.p=10001; @.q=10000; @.r=01111; @.s=01110; @.t=01101
@.u=01100; @.v=00100; @.w=01011; @.x=01010; @.y=01001; @.z=01000; @.?=00000
@.!=00101; @..=00110; _=',' ; @._=00001; _=' ' ; @._=00011
/* [↑] code supports some punctuation.*/
say ' plain text: ' plain /*display the original (plain) text. */
encoded=BaconEnc(plain) /*encode using a (full) Bacon cipher.*/
say 'cipher text: ' encoded /*display the ciphered (coded) text. */
decoded=BaconDec(encoded) /*decode ciphered text──►plain (almost)*/
say 'cycled text: ' decoded /*display the recycled text (~ plain),*/ exit /*stick a fork in it, we're all done. */ /*────────────────────────────────────────────────────────────────────────────*/ BaconEnc: procedure expose @.; arg x; $=; Lx=length(x)
do j=1 for Lx; _=substr(x,j,1); $=$ || @._; end
return $
/*────────────────────────────────────────────────────────────────────────────*/ BaconDec: procedure expose @.; parse arg x; $=; Lx=length(x)
do k=0 for 256; _=d2c(k); if @._== then iterate; q=@._; !.q=_; end
do j=1 to Lx by 5; y=substr(x,j,5); $=$ || !.y; end
return $</lang>
output when using the default input:
plain text: The quick brown fox jumped over the lazy dog. cipher text: 011011100011011000111000001100101111110110110000111111001111100100101110011000111101010010010100001100111011001010010001110111110000011100100010011011011110001101101110001101100011101011111101000010010001111100100101100100110 cycled text: THE QUICK BROWN FOX JUMPED OVER THE LAZY DOG.