NAME¶
Crypt::OpenSSL::Bignum - OpenSSL's multiprecision integer arithmetic
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";
}
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.
NOTE: Many of the methods in this package can croak, so use eval, or
Error.pm's try/catch mechanism to capture errors.
Class Methods¶
- 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.
- new_from_decimal
- Create a new Crypt::OpenSSL::Bignum object whose value is
specified by the given decimal representation.
- new_from_hex
- Create a new Crypt::OpenSSL::Bignum object whose value is
specified by the given hexidecimal representation.
- 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.
- zero
- Returns a new Crypt::OpenSSL::Bignum object representing
0
- one
- Returns a new Crypt::OpenSSL::Bignum object representing
1
- 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.
Instance Methods¶
- to_decimal
- Return a decimal string representation of this object.
- to_hex
- Return a hexidecimal string representation of this
object.
- 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.
- get_word
- Return a scalar integer representation of this object, if
it can be represented as an unsigned long.
- is_zero
- Returns true of this object represents 0.
- is_one
- Returns true of this object represents 1.
- is_odd
- Returns true of this object represents an odd number.
- copy
- Returns a copy of this object.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
AUTHOR¶
Ian Robertson, iroberts@cpan.org
SEE ALSO¶
perl,
bn(3ssl)