package Crypt::Perl::ECDSA::EncodedPoint;
use strict;
use warnings;
use Try::Tiny;
use Crypt::Perl::ECDSA::Utils ();
use Crypt::Perl::X ();
#input can be a string or BigInt,
#in any of “hybrid”, “uncompressed”, or “compressed” formats
sub new {
my ($class, $input) = @_;
my $bin;
my $input_is_obj;
if ( try { $input->isa('Crypt::Perl::BigInt') } ) {
$bin = $input->as_bytes();
$input_is_obj = 1;
}
else {
$input =~ s<\A\0+><>;
$bin = $input;
}
my $first_octet = ord substr( $bin, 0, 1 );
my $self = bless {}, $class;
#Accommodate “hybrid” points
if ($first_octet == 6 || $first_octet == 7) {
$self->{'_bin'} = "\x04" . substr( $bin, 1 );
}
elsif ($first_octet == 4) {
$self->{'_bin'} = $bin;
}
elsif ($first_octet == 2 || $first_octet == 3) {
$self->{'_compressed_bin'} = $bin;
}
else {
die Crypt::Perl::X::create('Generic', sprintf "Invalid leading octet in ECDSA point: %v02x", $bin);
}
return $self;
}
#returns a string
sub get_compressed {
my ($self) = @_;
return $self->{'_compressed_bin'} ||= do {
Crypt::Perl::ECDSA::Utils::compress_point( $self->{'_bin'} );
};
}
#returns a string
sub get_uncompressed {
my ($self, $curve_hr) = @_;
die "Need curve! (p, a, b)" if !$curve_hr;
return $self->{'_bin'} ||= do {
die "Need compressed bin!" if !$self->{'_compressed_bin'};
Crypt::Perl::ECDSA::Utils::decompress_point(
$self->{'_compressed_bin'},
@{$curve_hr}{ qw( p a b ) },
);
};
}
#If there’s ever a demand for “hybrid”:
#0x06 and 0x07 take the place of the uncompressed leading 0x04,
#analogous to 0x02 and 0x03 in the compressed form.
1;