NAME

Crypt::ECDSA::Curve::Koblitz -- binary (F(2**N)) curves for EC cryptography

DESCRIPTION

These are for use with Crypt::ECDSA, a Math::GMPz based cryptography module.

METHODS

new

Delegated to base class Crypt::ECDSA::Curve

reduce_F2m

Special binary field function--reduce the result of addition or multiplication on
the curve by the 'irreducible' basis polynomial.  Akin to modular addition, but slower :(.

multiply_F2m

Binary field multiplication

invert_F2m

Binary field inversion: used for binary field division, so that
  $x * $y             becomes 
  $x * invert_F2m($y)

is_on_curve

return 1 if (x, y) is on the curve, otherwise undef.

add_on_curve

Add a point on the curve to itself or another

subtract_on_curve

Subtract a point on the curve.  Same as addition.

double_on_curve

Double a point on the curve.   
Returns a new point, does NOT change the original.

inverse_on_curve

get a point's additive inverse

multiply_on_curve

my $Q = $G * n;

Multiply a curve point by a scalar.  
Note this should always be Point * scalar, not scalar * Point.

is_weak_curve

tests for known weak curve parameters

tau_point_multiply

Koblitz curve binary field point multiply algorithm from draft FIPS 186-3, pages 111-114  

FUNCTIONS

equation

Return ascii string representation of the field equation

BUGS

Windows compatibility needs work. Some of this is the GMP library.

AUTHOR

William Herrera B<wherrera@skylightview.com>. 

SUPPORT

Questions, feature requests and bug reports should go to <wherrera@skylightview.com>.

COPYRIGHT

Copyright (c) 2007 William Herrera. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.