Playfair cipher: Difference between revisions
(+ Python entry) |
(Better Python entry) |
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<lang python>from string import uppercase |
<lang python>from string import uppercase |
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from itertools import product |
from itertools import product |
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from re import findall |
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def uniq(seq): |
def uniq(seq): |
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seen = {} |
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for |
return [seen.setdefault(e, e) for e in seq if e not in seen] |
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if x not in checked: |
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checked.append(x) |
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return checked |
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def partition(seq, n): |
def partition(seq, n): |
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for row in m: |
for row in m: |
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for i, j in product(r5, repeat=2): |
for i, j in product(r5, repeat=2): |
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if i |
if i != j: |
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enc[row[i] + row[j]] = row[(i + 1) % 5] + row[(j + 1) % 5] |
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⚫ | |||
# Map pairs in same column. |
# Map pairs in same column. |
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for |
for c in zip(*m): |
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c = [row[r] for row in m] |
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for i, j in product(r5, repeat=2): |
for i, j in product(r5, repeat=2): |
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if i |
if i != j: |
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enc[c[i] + c[j]] = c[(i + 1) % 5] + c[(j + 1) % 5] |
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enc[c[i] + c[j]] = c[(i + 1) % 5] + c[(j + 1) % 5] |
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# Map pairs with cross-connections. |
# Map pairs with cross-connections. |
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for i1, j1, i2, j2 in product(r5, repeat=4): |
for i1, j1, i2, j2 in product(r5, repeat=4): |
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if i1 |
if i1 != i2 and j1 != j2: |
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continue |
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enc[m[i1][j1] + m[i2][j2]] = m[i1][j2] + m[i2][j1] |
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# Generate reverse translations. |
# Generate reverse translations. |
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def sub_enc(txt): |
def sub_enc(txt): |
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def splitter(seq): |
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return " ".join(enc[a + b if b else a + 'X'] for a, b in lst) |
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while True: |
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if i == len(seq) - 1: |
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yield seq[i] + "X" |
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break |
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if i >= len(seq): |
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break |
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if seq[i] == seq[i + 1]: |
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yield seq[i] + "X" |
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i += 1 |
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else: |
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yield seq[i : i + 2] |
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i += 2 |
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return " ".join(enc[p if len(p) == 2 else p + 'X'] for p in lst) |
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def sub_dec(encoded): |
def sub_dec(encoded): |
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def main(): |
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print "Encoded:", enc |
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main()</lang> |
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{{out}} |
{{out}} |
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<pre>Original: Hide the gold in...the TREESTUMP!!! |
<pre>Original: Hide the gold in...the TREESTUMP!!! |
Revision as of 16:48, 21 May 2013
Implement a Playfair cipher encryption and decryption.
The user must be able to choose J = I or no Q in the alphabet. The output of the encrypted and decrypted message must be in capitalized digraphs, separated by spaces.
Output example: HI DE TH EG OL DI NT HE TR EX ES TU MP.
C++
<lang cpp>#include <iostream>
- include <string>
using namespace std;
class playfair { public:
void doIt( string k, string t, bool ij, bool e ) {
createGrid( k, ij ); getTextReady( t, ij, e ); if( e ) doIt( 1 ); else doIt( -1 ); display();
}
private:
void doIt( int dir ) {
int a, b, c, d; string ntxt; for( string::const_iterator ti = _txt.begin(); ti != _txt.end(); ti++ ) { if( getCharPos( *ti++, a, b ) ) if( getCharPos( *ti, c, d ) ) { if( a == c ) { ntxt += getChar( a, b + dir ); ntxt += getChar( c, d + dir ); } else if( b == d ){ ntxt += getChar( a + dir, b ); ntxt += getChar( c + dir, d ); } else { ntxt += getChar( c, b ); ntxt += getChar( a, d ); } } } _txt = ntxt;
}
void display() {
cout << "\n\n OUTPUT:\n=========" << endl; string::iterator si = _txt.begin(); int cnt = 0; while( si != _txt.end() ) { cout << *si; si++; cout << *si << " "; si++; if( ++cnt >= 26 ) cout << endl, cnt = 0; } cout << endl << endl;
}
char getChar( int a, int b ) {
return _m[b % 5][a % 5];
}
bool getCharPos( char l, int &a, int &b ) {
for( int y = 0; y < 5; y++ ) for( int x = 0; x < 5; x++ ) if( _m[y][x] == l ) { a = x; b = y; return true; }
return false;
}
void getTextReady( string t, bool ij, bool e ) {
for( string::iterator si = t.begin(); si != t.end(); si++ ) { *si = toupper( *si ); if( *si < 65 || *si > 90 ) continue; if( *si == 'J' && ij ) *si = 'I'; else if( *si == 'Q' && !ij ) continue; _txt += *si; } if( e ) { string ntxt = ""; size_t len = _txt.length(); for( size_t x = 0; x < len; x += 2 ) { ntxt += _txt[x]; if( x + 1 < len ) { if( _txt[x] == _txt[x + 1] ) ntxt += 'X'; ntxt += _txt[x + 1]; } } _txt = ntxt; } if( _txt.length() & 1 ) _txt += 'X';
}
void createGrid( string k, bool ij ) {
if( k.length() < 1 ) k = "KEYWORD"; k += "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; string nk = ""; for( string::iterator si = k.begin(); si != k.end(); si++ ) { *si = toupper( *si ); if( *si < 65 || *si > 90 ) continue; if( ( *si == 'J' && ij ) || ( *si == 'Q' && !ij ) )continue; if( nk.find( *si ) == -1 ) nk += *si; } copy( nk.begin(), nk.end(), &_m[0][0] );
}
string _txt; char _m[5][5];
};
int main( int argc, char* argv[] ) {
string key, i, txt; bool ij, e; cout << "(E)ncode or (D)ecode? "; getline( cin, i ); e = ( i[0] == 'e' || i[0] == 'E' ); cout << "Enter a en/decryption key: "; getline( cin, key ); cout << "I <-> J (Y/N): "; getline( cin, i ); ij = ( i[0] == 'y' || i[0] == 'Y' ); cout << "Enter the text: "; getline( cin, txt ); playfair pf; pf.doIt( key, txt, ij, e ); return system( "pause" );
}</lang>
- Output:
(E)ncode or (D)ecode? e Enter a en/decryption key: playfair example I <-> J (Y/N): y Enter the text: Hide the gold in the tree stump
OUTPUT: ========= BM OD ZB XD NA BE KU DM UI XM MO UV IF
(E)ncode or (D)ecode? d Enter a en/decryption key: playfair example I <-> J (Y/N): y Enter the text: BMODZBXDNABEKUDMUIXMMOUVIFOUTPUT: ========= HI DE TH EG OL DI NT HE TR EX ES TU MP
Perl 6
<lang perl6># Instantiate a specific encoder/decoder.
sub playfair( $key,
$from = 'J',
$to = $from eq 'J' ?? 'I' !! ) {
sub canon($str) { $str.subst(/<-alpha>/,, :g).uc.subst(/$from/,$to,:g) }
# Build 5x5 matrix. my @m = canon($key ~ ('A'..'Z').join).comb.uniq.map:
-> $a,$b,$c,$d,$e { [$a,$b,$c,$d,$e] }
# Pregenerate all forward translations. my %ENC = gather {
# Map pairs in same row. for @m -> @r { for ^@r X ^@r -> \i,\j { next if i == j; take @r[i] ~ @r[j] => @r[(i+1)%5] ~ @r[(j+1)%5]; } }
# Map pairs in same column. for ^5 -> $c { my @c = @m.map: *.[$c]; for ^@c X ^@c -> \i,\j { next if i == j; take @c[i] ~ @c[j] => @c[(i+1)%5] ~ @c[(j+1)%5]; } }
# Map pairs with cross-connections. for ^5 X ^5 X ^5 X ^5 -> \i1,\j1,\i2,\j2 { next if i1 == i2 or j1 == j2; take @m[i1][j1] ~ @m[i2][j2] => @m[i1][j2] ~ @m[i2][j1]; }
}
# Generate reverse translations. my %DEC = %ENC.invert;
return
anon sub enc($red) { my @list = canon($red).comb(/(.) (.?) <?{ $1 ne $0 }>/); ~@list.map: { .chars == 1 ?? %ENC{$_~'X'} !! %ENC{$_} } }, anon sub dec($black) { my @list = canon($black).comb(/../); ~@list.map: { %DEC{$_} } } }
my (&encode,&decode) = playfair 'Playfair example';
my $orig = "Hide the gold in...the TREESTUMP!!!"; say " orig:\t$orig";
my $black = encode $orig; say "black:\t$black";
my $red = decode $black; say " red:\t$red";</lang>
- Output:
orig: Hide the gold in...the TREESTUMP!!! black: BM OD ZB XD NA BE KU DM UI XM MO UV IF red: HI DE TH EG OL DI NT HE TR EX ES TU MP
Python
<lang python>from string import uppercase from itertools import product from re import findall
def uniq(seq):
seen = {} return [seen.setdefault(e, e) for e in seq if e not in seen]
def partition(seq, n):
return [seq[i : i + n] for i in xrange(0, len(seq), n)]
"""Instantiate a specific encoder/decoder."""
def playfair(key, from_ = 'J', to = None):
if to is None: to = 'I' if from_ == 'J' else
def canonicalize(s): return filter(lambda c: c in uppercase, s.upper()).replace(from_, to)
# Build 5x5 matrix. m = partition(uniq(canonicalize(key + uppercase)), 5)
# Pregenerate all forward translations. r5 = xrange(5) enc = {}
# Map pairs in same row. for row in m: for i, j in product(r5, repeat=2): if i != j: enc[row[i] + row[j]] = row[(i + 1) % 5] + row[(j + 1) % 5]
# Map pairs in same column. for c in zip(*m): for i, j in product(r5, repeat=2): if i != j: enc[c[i] + c[j]] = c[(i + 1) % 5] + c[(j + 1) % 5]
# Map pairs with cross-connections. for i1, j1, i2, j2 in product(r5, repeat=4): if i1 != i2 and j1 != j2: enc[m[i1][j1] + m[i2][j2]] = m[i1][j2] + m[i2][j1]
# Generate reverse translations. dec = dict((v, k) for k, v in enc.iteritems())
def sub_enc(txt): lst = findall(r"(.)(?:(?!\1)(.))?", canonicalize(txt)) return " ".join(enc[a + b if b else a + 'X'] for a, b in lst)
def sub_dec(encoded): return " ".join(dec[p] for p in partition(canonicalize(encoded), 2))
return sub_enc, sub_dec
(encode, decode) = playfair("Playfair example")
orig = "Hide the gold in...the TREESTUMP!!!"
print "Original:", orig
enc = encode(orig)
print "Encoded:", enc
print "Decoded:", decode(enc)</lang>
- Output:
Original: Hide the gold in...the TREESTUMP!!! Encoded: BM OD ZB XD NA BE KU DM UI XM MO UV IF Decoded: HI DE TH EG OL DI NT HE TR EX ES TU MP