Bacon cipher: Difference between revisions
Added XPL0 example.
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System.print("\nHidden text ->\n\n%(decodedText)")</syntaxhighlight>
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<pre>
Cipher text ->
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 An
Hidden text ->
the quick brown fox jumps over the lazy dog
</pre>
=={{header|XPL0}}==
{{trans|C}}
Works on Raspberry Pi. (MAlloc works differently in other versions.)
<syntaxhighlight lang "XPL0">include xpllib; \for StrCmp, StrLen, Print, ToLower, StrNCopy
int Codes;
func GetCode(C);
char C;
[if C >= 97 and C <= 122 then return Codes(C-97);
return Codes(26);
];
func GetChar(Code);
char Code;
int I;
[if StrCmp(Codes(26), Code) = 0 then return ^ ;
for I:= 0 to 26-1 do
if StrCmp(Codes(I), Code) = 0 then return 97+I;
Print("\nCode ^"%s^" is invalid\n", Code);
exit(1);
];
proc StrToLower(S);
char S;
int I;
for I:= 0 to StrLen(S)-1 do S(I):= ToLower(S(I));
func BaconEncode(PlainText, Message);
char PlainText, Message;
int I, Count;
int PLen, MLen, ELen;
char C, P, Et, Mt;
[PLen:= StrLen(PlainText);
MLen:= StrLen(Message);
ELen:= 5 * PLen;
Et:= MAlloc(ELen+1);
StrToLower(PlainText);
P:= Et;
for I:= 0 to PLen-1 do
[C:= PlainText(I);
StrNCopy(P, GetCode(C), 5);
P:= P+5;
];
P:= P+1; P(0):= 0;
\'A's to be in lowercase, 'B's in uppercase
StrToLower(Message);
Mt:= MAlloc(MLen+1);
Count:= 0;
for I:= 0 to MLen-1 do
[C:= Message(I);
if C >= ^a and C <= ^z then
[if Et(Count) = ^A then Mt(I):= C
else Mt(I):= C-32; \uppercase equivalent
Count:= Count+1;
if Count = ELen then I:= MLen;
]
else Mt(I):= C;
];
Release(Et);
return Mt;
];
func BaconDecode(CipherText);
char CipherText;
int I, Count, CLen, PLen;
char P, Ct, Pt, C, Quintet(6);
[CLen:= StrLen(CipherText);
Ct:= MAlloc(CLen+1);
Count:= 0;
for I:= 0 to CLen-1 do
[C:= CipherText(I);
if C >= ^a and C <= ^z then
[Ct(Count):= ^A; Count:= Count+1]
else if C >= ^A and C <= ^Z then
[Ct(Count):= ^B; Count:= Count+1];
];
PLen:= StrLen(Ct) / 5;
Pt:= MAlloc(PLen+1);
P:= Ct;
for I:= 0 to PLen-1 do
[StrNCopy(Quintet, P, 5);
Quintet(5):= 0;
Pt(I):= GetChar(Quintet);
P:= P+5;
];
Pt(PLen):= 0;
Release(Ct);
return Pt;
];
char PlainText, Message, CipherText, HiddenText;
[\Maps successively from 'a' to 'z' plus ' ' to denote any non-letter
Codes:= ["AAAAA", "AAAAB", "AAABA", "AAABB", "AABAA",
"AABAB", "AABBA", "AABBB", "ABAAA", "ABAAB",
"ABABA", "ABABB", "ABBAA", "ABBAB", "ABBBA",
"ABBBB", "BAAAA", "BAAAB", "BAABA", "BAABB",
"BABAA", "BABAB", "BABBA", "BABBB", "BBAAA",
"BBAAB", "BBBAA"];
PlainText:= "the quick brown fox jumps over the lazy dog";
Message:= "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 may optionally be extended to encode all lower
case characters individually and/or adding a few punctuation characters
such as the space.";
CipherText:= BaconEncode(PlainText, Message);
Print("Cipher text ->\n\n%s\n", CipherText);
HiddenText:= BaconDecode(CipherText);
Print("\nHidden text ->\n\n%s\n", HiddenText);
Release(CipherText);
Release(HiddenText);
]</syntaxhighlight>
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<pre>
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