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1 | # -*-perl-*- |
2 | # |
3 | # $Id$ |
4 | # |
5 | # Field abstraction |
6 | # |
7 | # (c) 2004 Straylight/Edgeware |
8 | # |
9 | |
10 | #----- Licensing notice ----------------------------------------------------- |
11 | # |
12 | # This file is part of the Perl interface to Catacomb. |
13 | # |
14 | # Catacomb/Perl is free software; you can redistribute it and/or modify |
15 | # it under the terms of the GNU General Public License as published by |
16 | # the Free Software Foundation; either version 2 of the License, or |
17 | # (at your option) any later version. |
18 | # |
19 | # Catacomb/Perl is distributed in the hope that it will be useful, |
20 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | # GNU General Public License for more details. |
23 | # |
24 | # You should have received a copy of the GNU General Public License |
25 | # along with Catacomb/Perl; if not, write to the Free Software Foundation, |
26 | # Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | |
28 | #----- Abstract fields ------------------------------------------------------ |
29 | |
30 | package Catacomb::Field; |
31 | use Carp; |
32 | use Catacomb::Base; |
33 | use Catacomb::Cache; |
34 | |
35 | $cache = Catacomb::Cache->new(); |
36 | |
37 | sub intern { |
38 | croak("USage: Catacomb::Field::intern(f)") unless @_ == 1; |
39 | my ($f) = @_; |
40 | return $cache->intern($f); |
41 | } |
42 | |
43 | sub elt { |
44 | croak("Usage: Catacomb::Field::elt(f, x)") unless @_ == 2; |
45 | my ($f, $x) = @_; |
46 | return Catacomb::Field::Elt->new($f, $x); |
47 | } |
48 | |
49 | sub zero { |
50 | croak("Usage: Catacomb::Field::zero(f)") unless @_ == 1; |
51 | my ($f) = @_; |
52 | return Catacomb::Field::Elt->new($f, $f->_zero()); |
53 | } |
54 | |
55 | sub one { |
56 | croak("Usage: Catacomb::Field::one(f)") unless @_ == 1; |
57 | my ($f) = @_; |
58 | return Catacomb::Field::Elt->new($f, $f->_one()); |
59 | } |
60 | |
61 | sub rand { |
62 | croak("Usage: Catacomb::Field::rand(f, [rng])") |
63 | unless @_ >= 1 && @_ <= 2; |
64 | my ($f, $rng) = @_; |
65 | $rng ||= $Catacomb::random; |
66 | return Catacomb::Field::Elt->new($f, $f->_one($rng)); |
67 | } |
68 | |
69 | sub div { |
70 | croak("Usage: Catacomb::Field::div(f, x, y)") unless @_ == 3; |
71 | my ($f, $x, $y) = @_; |
72 | return $f->mul($x, $f->inv($y)); |
73 | } |
74 | |
75 | sub primecurve { |
76 | croak("Usage: Catacomb::Field::primecurve(f, a, b)") unless @_ == 3; |
77 | my ($f, $a, $b) = @_; |
78 | croak("not a prime field") unless $f->type == Catacomb::FTY_PRIME; |
79 | return Catacomb::EC::Curve->prime($f, $a, $b); |
80 | } |
81 | |
82 | sub primeprojcurve { |
83 | croak("Usage: Catacomb::Field::primeprojcurve(f, a, b)") unless @_ == 3; |
84 | my ($f, $a, $b) = @_; |
85 | croak("not a prime field") unless $f->type == Catacomb::FTY_PRIME; |
86 | return Catacomb::EC::Curve->primeproj($f, $a, $b); |
87 | } |
88 | |
89 | sub bincurve { |
90 | croak("Usage: Catacomb::Field::bincurve(f, a, b)") unless @_ == 3; |
91 | my ($f, $a, $b) = @_; |
92 | croak("not a prime field") unless $f->type == Catacomb::FTY_BINARY; |
93 | return Catacomb::EC::Curve->bincurve($f, $a, $b); |
94 | } |
95 | |
96 | sub binprojcurve { |
97 | croak("Usage: Catacomb::Field::binprojcurve(f, a, b)") unless @_ == 3; |
98 | my ($f, $a, $b) = @_; |
99 | croak("not a prime field") unless $f->type == Catacomb::FTY_BINARY; |
100 | return Catacomb::EC::Curve->binproj($f, $a, $b); |
101 | } |
102 | |
103 | #----- Field elements ------------------------------------------------------- |
104 | |
105 | package Catacomb::Field::Elt; |
106 | use Carp; |
107 | use Catacomb::Base; |
108 | |
109 | sub _elt { bless [@_], Catacomb::Field::Elt; } |
110 | |
111 | sub new { |
112 | croak("Usage: Catacomb::Field::Elt::new(me, f, x)"), unless @_ == 3; |
113 | my ($me, $f, $x) = @_; |
114 | my $r; |
115 | ($f, $r) = $f->intern(); |
116 | return _elt($f->in($x), $f, $r); |
117 | } |
118 | |
119 | sub field { |
120 | croak("Usage: Catacomb::Field::Elt::field(e)") unless @_ == 1; |
121 | return $_[0][1]; |
122 | } |
123 | |
124 | sub value { |
125 | croak("Usage: Catacomb::Field::Elt::value(e)") unless @_ == 1; |
126 | return $_[0][1]->out($_[0][0]); |
127 | } |
128 | |
129 | sub elt { |
130 | croak("Usage: Catacomb::Field::Elt::elt(e, x)") unless @_ == 2; |
131 | my ($e, $x) = @_; |
132 | my $f = $e->[1]; |
133 | return _elt($f->in($x), $f, $e->[2]); |
134 | } |
135 | |
136 | sub tostring { |
137 | croak("Usage: Catacomb::Field::Elt::tostring(e, [radix])") |
138 | unless @_ >= 1 && @_ <= 2; |
139 | my ($e, $radix) = @_; |
140 | $radix = 16 unless defined($radix); |
141 | return $e->value()->tostring($radix); |
142 | } |
143 | |
144 | sub _convert { |
145 | my ($x, $f, $r) = @_; |
146 | if (UNIVERSAL::isa($x, Catacomb::Field::Elt)) { |
147 | croak("field mismatch") unless $f == $x->[1]; |
148 | return $x; |
149 | } |
150 | if ($x == 0) { |
151 | return _elt($f->_zero(), $f, $r); |
152 | } |
153 | if ($x == 1) { |
154 | return _elt($f, $f->_one(), $f, $r); |
155 | } |
156 | croak("can't convert to field element"); |
157 | } |
158 | |
159 | sub _binop { |
160 | my ($op, $x, $y, $swap) = @_; |
161 | my $f = $x->[1]; |
162 | my $r = $x->[2]; |
163 | $y = _convert($y, $f, $r); |
164 | my $z = $swap ? |
165 | &$op($f, $x->[0], $y->[0]) : |
166 | &$op($f, $y->[0], $x->[0]); |
167 | return _elt($z, $f, $r); |
168 | } |
169 | |
170 | sub _unop { |
171 | my ($op, $x) = @_; |
172 | my $f = $x->[1]; |
173 | my $r = $x->[2]; |
174 | my $z = &$op($f, $x->[0]); |
175 | return _elt($z, $f, $r); |
176 | } |
177 | |
178 | sub exp { |
179 | croak("Usage: Catacomb::Field::Elt::exp(x, n)") unless @_ == 2; |
180 | my ($x, $n) = @_; |
181 | my ($xx, $f, $fr) = @$x; |
182 | return _elt($f->exp($xx, $n), $f, $fr); |
183 | } |
184 | |
185 | sub sqrt { |
186 | croak("Usage: Catacomb::Field::Elt::sqrt(x)") unless @_ == 1; |
187 | my ($x) = @_; |
188 | my ($xx, $f, $fr) = @$x; |
189 | return _elt($f->sqrt($xx), $f, $fr); |
190 | } |
191 | |
192 | sub zerop { |
193 | croak("Usage: Catacomb::Field::Elt::zerop(x)") unless @_ == 1; |
194 | my ($x) = @_; |
195 | my ($xx, $f, $fr) = @$x; |
196 | return $f->zero($xx); |
197 | } |
198 | |
199 | sub _eq { |
200 | my ($x, $y) = @_; |
201 | $y = _convert($y, $x->[1], $x->[2]); |
202 | return Catacomb::MP::eq($x->[0], $y->[0]); |
203 | } |
204 | |
205 | use overload |
206 | '+' => sub { _binop(\&Catacomb::Field::add, @_); }, |
207 | '-' => sub { _binop(\&Catacomb::Field::sub, @_); }, |
208 | '*' => sub { _binop(\&Catacomb::Field::mul, @_); }, |
209 | '/' => sub { _binop(\&Catacomb::Field::div, @_); }, |
210 | '**' => sub { &exp($_[0], $_[1]); }, |
211 | '==' => sub { _eq(@_); }, |
212 | '!=' => sub { !_eq(@_); }, |
213 | 'eq' => sub { _eq(@_); }, |
214 | 'ne' => sub { !_eq(@_); }, |
215 | '""' => sub { "0x" . $_[0]->tostring(16); }, |
216 | '0+' => sub { $_[0][1]->toint(); }, |
217 | 'sqrt' => sub { _unop(\&Catacomb::Field::sqrt, @_); }, |
218 | 'neg' => sub { _unop(\&Catacomb::Field::neg, @_); }; |
219 | |
220 | sub inv { _unop(\&Catacomb::Field::inv, @_); } |
221 | |
222 | #----- That's all, folks ---------------------------------------------------- |