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Crypt::Mode::CTR(3)   User Contributed Perl Documentation  Crypt::Mode::CTR(3)

NAME
       Crypt::Mode::CTR	- Block	cipher mode CTR	[Counter mode]

SYNOPSIS
	  use Crypt::Mode::CTR;
	  my $m	= Crypt::Mode::CTR->new('AES');

	  #(en|de)crypt	at once
	  my $ciphertext = $m->encrypt($plaintext, $key, $iv);
	  my $plaintext	= $m->decrypt($ciphertext, $key, $iv);

	  #encrypt more	chunks
	  $m->start_encrypt($key, $iv);
	  my $ciphertext = $m->add('some data');
	  $ciphertext .= $m->add('more data');

	  #decrypt more	chunks
	  $m->start_decrypt($key, $iv);
	  my $plaintext	= $m->add($some_ciphertext);
	  $plaintext .=	$m->add($more_ciphertext);

DESCRIPTION
       This module implements CTR cipher mode. NOTE: it	works only with
       ciphers from CryptX (Crypt::Cipher::NNNN).

METHODS
   new
	my $m =	Crypt::Mode::CTR->new($cipher_name);
	#or
	my $m =	Crypt::Mode::CTR->new($cipher_name, $ctr_mode, $ctr_width);
	#or
	my $m =	Crypt::Mode::CTR->new($cipher_name, $ctr_mode, $ctr_width, $cipher_rounds);

	# $cipher_name .. one of 'AES',	'Anubis', 'Blowfish', 'CAST5', 'Camellia', 'DES', 'DES_EDE',
	#		  'KASUMI', 'Khazad', 'MULTI2',	'Noekeon', 'RC2', 'RC5', 'RC6',
	#		  'SAFERP', 'SAFER_K128', 'SAFER_K64', 'SAFER_SK128', 'SAFER_SK64',
	#		  'SEED', 'Skipjack', 'Twofish', 'XTEA', 'IDEA', 'Serpent'
	#		  simply any <NAME> for	which there exists Crypt::Cipher::<NAME>
	# $ctr_mode ..... 0 little-endian counter (DEFAULT)
	#		  1 big-endian counter
	#		  2 little-endian + RFC3686 incrementing
	#		  3 big-endian + RFC3686 incrementing
	# $ctr_width .... counter width	in bytes (DEFAULT = full block width)
	# $cipher_rounds ... optional num of rounds for	given cipher

   encrypt
	  my $ciphertext = $m->encrypt($plaintext, $key, $iv);

   decrypt
	  my $plaintext	= $m->decrypt($ciphertext, $key, $iv);

   start_encrypt
	  $m->start_encrypt($key, $iv);

   start_decrypt
	  $m->start_decrypt($key, $iv);

   add
	  # in encrypt mode
	  my $plaintext	= $m->add($ciphertext);

	  # in decrypt mode
	  my $ciphertext = $m->add($plaintext);

SEE ALSO
       o   CryptX, Crypt::Cipher

       o   Crypt::Cipher::AES, Crypt::Cipher::Blowfish,	...

       o   <https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Counter_.28CTR.29>

perl v5.32.0			  2020-08-25		   Crypt::Mode::CTR(3)

NAME | SYNOPSIS | DESCRIPTION | METHODS | SEE ALSO

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<https://www.freebsd.org/cgi/man.cgi?query=Crypt::Mode::CTR&sektion=3&manpath=FreeBSD+12.2-RELEASE+and+Ports>

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