Playfair cipher: Difference between revisions
(Created page with "{{draft task}} 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 th...") |
(First blood! :)) |
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Output example: HI DE TH EG OL DI NT HE TR EX ES TU MP. |
Output example: HI DE TH EG OL DI NT HE TR EX ES TU MP. |
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=={{header|Perl 6}}== |
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<lang perl6># Instantiate a specific encoder/decoder. |
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sub playfair( $key, |
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$from = 'J', |
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$to = $from eq 'J' ?? 'I' !! '' |
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) { |
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sub canon($str) { $str.subst(/<-alpha>/,'', :g).uc.subst(/$from/,$to,:g) } |
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# Build 5x5 matrix. |
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my @m = canon($key ~ ('A'..'Z').join).comb.uniq.map: |
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-> $a,$b,$c,$d,$e { [$a,$b,$c,$d,$e] } |
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# Pregenerate all forward translations. |
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my %ENC = gather { |
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# Map pairs in same row. |
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for @m -> @r { |
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for ^@r X ^@r -> \i,\j { |
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next if i == j; |
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take @r[i] ~ @r[j] => @r[(i+1)%5] ~ @r[(j+1)%5]; |
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} |
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} |
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# Map pairs in same column. |
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for ^5 -> $c { |
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my @c = @m.map: *.[$c]; |
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for ^@c X ^@c -> \i,\j { |
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next if i == j; |
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take @c[i] ~ @c[j] => @c[(i+1)%5] ~ @c[(j+1)%5]; |
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} |
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} |
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# Map pairs with cross-connections. |
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for ^5 X ^5 X ^5 X ^5 -> \i1,\j1,\i2,\j2 { |
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next if i1 == i2 or j1 == j2; |
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take @m[i1][j1] ~ @m[i2][j2] => @m[i1][j2] ~ @m[i2][j1]; |
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} |
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} |
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# Generate reverse translations. |
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my %DEC = %ENC.invert; |
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return |
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anon sub enc($red) { |
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my @list = canon($red).comb(/(.) (.?) <?{ $1 ne $0 }>/); |
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~@list.map: { .chars == 1 ?? %ENC{$_~'X'} !! %ENC{$_} } |
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}, |
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anon sub dec($black) { |
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my @list = canon($black).comb(/../); |
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~@list.map: { %DEC{$_} } |
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} |
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} |
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my (&encode,&decode) = playfair 'Playfair example'; |
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my $orig = "Hide the gold in...the TREESTUMP!!!"; |
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say " orig:\t$orig"; |
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my $black = encode $orig; |
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say "black:\t$black"; |
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my $red = decode $black; |
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say " red:\t$red";</lang> |
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{{out}} |
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<pre> orig: Hide the gold in...the TREESTUMP!!! |
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black: BM OD ZB XD NA BE KU DM UI XM MO UV IF |
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red: HI DE TH EG OL DI NT HE TR EX ES TU MP</pre> |
Revision as of 22:38, 11 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 message must be in capitalized digraphs, separated by spaces.
Output example: 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