package Crypt::OpenSSL::Bignum; use 5.005; use strict; use Carp; use vars qw( $VERSION @ISA ); require DynaLoader; @ISA = qw(DynaLoader); $VERSION = '0.04'; bootstrap Crypt::OpenSSL::Bignum $VERSION; sub DESTROY { shift->_free_BN(); } sub bless_pointer { my( $proto, $p_pointer ) = @_; return bless( \$p_pointer, $proto ); } sub equals { my( $self, $a ) = @_; return ! $self->cmp( $a ); } 1; __END__ =head1 NAME Crypt::OpenSSL::Bignum - OpenSSL's multiprecision integer arithmetic =head1 SYNOPSIS use Crypt::OpenSSL::Bignum; my $bn = Crypt::OpenSSL::Bignum->new_from_decimal( "1000" ); # or my $bn = Crypt::OpenSSL::Bignum->new_from_word( 1000 ); # or my $bn = Crypt::OpenSSL::Bignum->new_from_hex("0x3e8"); # or my $bn = Crypt::OpenSSL::Bignum->new_from_bin(pack( "C*", 3, 232 )) use Crypt::OpenSSL::Bignum::CTX; sub print_factorial { my( $n ) = @_; my $fac = Crypt::OpenSSL::Bignum->one(); my $ctx = Crypt::OpenSSL::Bignum::CTX->new(); foreach my $i (1 .. $n) { $fac->mul( Crypt::OpenSSL::Bignum->new_from_word( $i ), $ctx, $fac ); } print "$n factorial is ", $fac->to_decimal(), "\n"; } =head1 DESCRIPTION Crypt::OpenSSL::Bignum provides access to OpenSSL multiprecision integer arithmetic libraries. Presently, many though not all of the arithmetic operations that OpenSSL provides are exposed to perl. In addition, this module can be used to provide access to bignum values produced by other OpenSSL modules, such as key parameters from Crypt::OpenSSL::RSA. I<NOTE>: Many of the methods in this package can croak, so use eval, or Error.pm's try/catch mechanism to capture errors. =head1 Class Methods =over =item new_from_word Create a new Crypt::OpenSSL::Bignum object whose value will be the word given. Note that numbers represneted by objects created using this method are necessarily between 0 and 2^32 - 1. =item new_from_decimal Create a new Crypt::OpenSSL::Bignum object whose value is specified by the given decimal representation. =item new_from_hex Create a new Crypt::OpenSSL::Bignum object whose value is specified by the given hexidecimal representation. =item new_from_bin Create a new Crypt::OpenSSL::Bignum object whose value is specified by the given packed binary string. Note that objects created using this method are necessarily nonnegative. =item zero Returns a new Crypt::OpenSSL::Bignum object representing 0 =item one Returns a new Crypt::OpenSSL::Bignum object representing 1 =item bless_pointer Given a pointer to a OpenSSL BIGNUM object in memory, construct and return Crypt::OpenSSL::Bignum object around this. Note that the underlying BIGNUM object will be destroyed (via BN_clear_free(3ssl)) when the returned Crypt::OpenSSL::Bignum object is no longer referenced, so the pointer passed to this method should only be referenced via the returned perl object after calling bless_pointer. This method is intended only for use by XSUB writers writing code that interfaces with OpenSSL library methods, and who wish to be able to return a BIGNUM structure to perl as a Crypt::OpenSSL::Bignum object. =back =head1 Instance Methods =over =item to_decimal Return a decimal string representation of this object. =item to_hex Return a hexidecimal string representation of this object. =item to_bin Return a packed binary string representation of this object. Note that sign is ignored, so that to bin called on a Crypt::OpenSSL::Bignum object representing a negative number returns the same value as it would called on an object representing that number's absolute value. =item get_word Return a scalar integer representation of this object, if it can be represented as an unsigned long. =item is_zero Returns true of this object represents 0. =item is_one Returns true of this object represents 1. =item is_odd Returns true of this object represents an odd number. =item copy Returns a copy of this object. =item add This method returns the sum of this object and the first argument. If only one argument is passed, a new Crypt::OpenSSL::Bignum object is created for the return value; otherwise, the value of second argument is set to the result and returned. =item sub This method returns the difference of this object and the first argument. If only one argument is passed, a new Crypt::OpenSSL::Bignum object is created for the return value; otherwise, the value of second argument is set to the result and returned. =item mul This method returns the product of this object and the first argument, using the second argument, a Crypt::OpenSSL::Bignum::CTX object, as a scratchpad. If only two arguments are passed, a new Crypt::OpenSSL::Bignum object is created for the return value; otherwise, the value of third argument is set to the result and returned. =item div This method returns a list consisting of quotient and the remainder obtained by dividing this object by the first argument, using the second argument, a Crypt::OpenSSL::Bignum::CTX object, as a scratchpad. If only two arguments are passed, new Crypt::OpenSSL::Bignum objects is created for both return values. If a third argument is passed, otherwise, the value of third argument is set to the quotient. If a fourth argument is passed, the value of the fourth argument is set to the remainder. =item exp This method returns the product of this object exponeniated by the first argument, using the second argument, a Crypt::OpenSSL::Bignum::CTX object, as a scratchpad. =item mod_exp This method returns the product of this object exponeniated by the first argument, modulo the second argument, using the third argument, a Crypt::OpenSSL::Bignum::CTX object, as a scratchpad. =item pointer_copy This method is intended only for use by XSUB writers wanting to have access to the underlying BIGNUM structure referenced by a Crypt::OpenSSL::Bignum perl object so that they can pass them to other routines in the OpenSSL library. It returns a perl scalar whose IV can be cast to a BIGNUM* value. This can then be passed to an XSUB which can work with the BIGNUM directly. Note that the BIGNUM object pointed to will be a copy of the BIGNUM object wrapped by the instance; it is thus the responsiblity of the client to free space allocated by this BIGNUM object if and when it is done with it. See also bless_pointer. =back =head1 AUTHOR Ian Robertson, iroberts@cpan.org =head1 SEE ALSO L<perl>, L<bn(3ssl)> =cut