Crypt::Checksum::CRC32(3) User Contributed Perl Documentation
NAME
Crypt::Checksum::CRC32 - Compute CRC32 checksum
SYNOPSIS
### Functional interface:
use Crypt::Checksum::CRC32 ':all';
# calculate CRC32 checksum from string/buffer
my $data = 'data string';
my $checksum_raw = crc32_data($data);
my $checksum_hex = crc32_data_hex($data);
my $checksum_int = crc32_data_int($data);
# or from file
my $checksum_file_raw = crc32_file('filename.dat');
my $checksum_file_hex = crc32_file_hex('filename.dat');
my $checksum_file_int = crc32_file_int('filename.dat');
# or from filehandle
my $filehandle = ...; # existing binary-mode filehandle
my $checksum_fh_raw = crc32_file($filehandle);
my $checksum_fh_hex = crc32_file_hex($filehandle);
my $checksum_fh_int = crc32_file_int($filehandle);
### OO interface:
use Crypt::Checksum::CRC32;
my $d = Crypt::Checksum::CRC32->new;
$d->add('any data');
$d->add('another data');
my $checksum_raw = $d->digest; # raw 4 bytes
my $checksum_hex = $d->hexdigest; # hexadecimal form
my $checksum_int = $d->intdigest; # 32-bit unsigned integer
# or checksum a file instead
my $checksum_file_raw = Crypt::Checksum::CRC32->new->addfile('filename.dat')->digest;
DESCRIPTION
Computes CRC-32 checksums using the ISO 3309 / ITU-T V.42 polynomial
(0xEDB88320, also known as CRC-32/ISO-HDLC). This is the same variant
used by Ethernet (IEEE 802.3), PKZIP, gzip, and PNG.
Updated: v0.057
EXPORT
Nothing is exported by default.
You can export selected functions:
use Crypt::Checksum::CRC32 qw(crc32_data crc32_data_hex crc32_data_int crc32_file crc32_file_hex crc32_file_int);
Or all of them at once:
use Crypt::Checksum::CRC32 ':all';
FUNCTIONS
crc32_data
Returns the checksum as raw octets.
my $checksum_raw = crc32_data('data string');
#or
my $checksum_raw = crc32_data('any data', 'more data', 'even more data');
crc32_data_hex
Returns checksum as a hexadecimal string.
my $checksum_hex = crc32_data_hex('data string');
#or
my $checksum_hex = crc32_data_hex('any data', 'more data', 'even more data');
crc32_data_int
Returns checksum as unsigned 32-bit integer.
my $checksum_int = crc32_data_int('data string');
#or
my $checksum_int = crc32_data_int('any data', 'more data', 'even more data');
Each "crc32_data*" function converts its data arguments to bytes using
Perl's usual scalar stringification. Defined scalars, including numbers
and string-overloaded objects, are accepted. "undef" is treated as an
empty string and may emit Perl's usual "uninitialized value" warning.
crc32_file
Returns the checksum as raw octets.
my $checksum_raw = crc32_file('filename.dat');
#or
my $filehandle = ...; # existing binary-mode filehandle
my $checksum_raw = crc32_file($filehandle);
crc32_file_hex
Returns checksum as a hexadecimal string.
my $checksum_hex = crc32_file_hex('filename.dat');
#or
my $filehandle = ...; # existing binary-mode filehandle
my $checksum_hex = crc32_file_hex($filehandle);
crc32_file_int
Returns checksum as unsigned 32-bit integer.
my $checksum_int = crc32_file_int('filename.dat');
#or
my $filehandle = ...; # existing binary-mode filehandle
my $checksum_int = crc32_file_int($filehandle);
METHODS
Unless noted otherwise, assume $d is an existing checksum object
created via "new".
new
Constructor, returns a reference to the checksum object.
my $d = Crypt::Checksum::CRC32->new;
clone
Creates a copy of the checksum object state and returns a reference to
the copy.
$d->clone();
reset
Reinitialize the checksum object state and returns a reference to the
checksum object.
$d->reset();
add
All arguments are appended to the message we calculate checksum for.
The return value is the checksum object itself.
Each argument is converted to bytes using Perl's usual scalar
stringification. Defined scalars, including numbers and
string-overloaded objects, are accepted. "undef" is treated as an
empty string and may emit Perl's usual "uninitialized value" warning.
$d->add('any data');
#or
$d->add('any data', 'more data', 'even more data');
addfile
The content of the file (or filehandle) is appended to the message we
calculate checksum for. The return value is the checksum object
itself.
$d->addfile('filename.dat');
#or
my $filehandle = ...; # existing binary-mode filehandle
$d->addfile($filehandle);
Note: The filehandle must be in binary mode before you pass it to
addfile().
digest
Returns the binary checksum (raw bytes). This method does not alter
the object state, so you can call it repeatedly and continue with add()
or addfile() afterwards.
my $result_raw = $d->digest();
hexdigest
Returns the checksum encoded as a hexadecimal string. Like digest(),
this method does not alter the object state.
my $result_hex = $d->hexdigest();
intdigest
Returns the checksum encoded as unsigned 32-bit integer. Like
digest(), this method does not alter the object state.
my $result_int = $d->intdigest();
SEE ALSO
o CryptX(3)
o <https://en.wikipedia.org/wiki/Cyclic_redundancy_check>
perl v5.34.3 2026-05-11 Crypt::Checksum::CRC32(3)
cryptx 0.89.0 - Generated Mon May 11 08:06:01 CDT 2026