Crypt::Digest::SHAKE(3)

NAME
Crypt::Digest::SHAKE - Hash functions SHAKE128, SHAKE256 from SHA3 family

SYNOPSIS
   use Crypt::Digest::SHAKE;

   my $d = Crypt::Digest::SHAKE->new(128);
   $d->add('any data');
   my $part1 = $d->done(100); # 100 raw bytes
   my $part2 = $d->done(100); # another 100 raw bytes
   #...

   # or absorb input from a file instead
   my $file_d = Crypt::Digest::SHAKE->new(128);
   $file_d->addfile('filename.dat');
   my $file_part1 = $file_d->done(100);

DESCRIPTION
Provides an interface to the SHA3's sponge function SHAKE.

This is an XOF (extendable output function). Feed input with "add()" / "addfile()", then read output with one or more "done($len)" calls. After the first "done()", treat the object as being in output mode: do not call "add()" again on that state. Use "reset()" or a new object to start hashing a new message.

METHODS
Unless noted otherwise, assume $d is an existing SHAKE object created via "new", for example:

 my $d = Crypt::Digest::SHAKE->new(128);

  new
 my $d = Crypt::Digest::SHAKE->new($num);
 # $num ... [integer] 128 or 256 (selects SHAKE128 or SHAKE256)

  clone
 my $d2 = $d->clone();

  reset
 $d->reset();

  add
Appends data to the message. Returns the object itself (for chaining).

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
Reads the file content and appends it to the message. Returns the object itself (for chaining).

 $d->addfile('filename.dat');
 #or
 my $filehandle = ...; # existing binary-mode filehandle
 $d->addfile($filehandle);

  done
Returns $len bytes of output as a binary string. Can be called repeatedly to stream an unlimited amount of output from the same absorbed input. The $len argument is required and must be a positive integer. Single "done()" calls are limited to 1,000,000,000 bytes, but the recommended way to read large output is to call "done()" repeatedly in 10 MB chunks.

After the first "done()" call the object is in output mode. Calling "add()" in this state croaks; use "reset()" or create a new object to hash a different message.

 my $result_raw = $d->done($len);
 # can be called multiple times; $len is the number of output bytes to read
 # after the first done(), add() croaks until you call reset()

SEE ALSO

•   CryptX, Crypt::Digest

•   <https://csrc.nist.gov/pubs/fips/202/final>