There's no reason not to use Crypt::CBC.
Unless performance is important. 
use strict;
use warnings;

use Crypt::CBC;
use Crypt::Rijndael;
use Crypt::GCrypt;

my $cbc = Crypt::CBC->new(
    -key    => 'a' x 32,
    -cipher => 'Rijndael'
);
$cbc->start('encrypting');
my $rij = Crypt::Rijndael->new( 'a' x 32, Crypt::Rijndael::MODE_CBC );
my $gcry = Crypt::GCrypt->new(
    type      => 'cipher',
    algorithm => 'rijndael',
    mode      => 'cbc'
);
$gcry->start('encrypting');
$gcry->setkey( 'a' x 32 );
$gcry->setiv( 'b' x 16 );

my $plaintext = 'plain text' x 8192;

use Benchmark qw( cmpthese );

cmpthese - 10,
  {
    'Crypt::CBC'      => sub { $cbc->crypt($plaintext); },
    'Crypt::Rijndael' => sub { $rij->encrypt($plaintext); },
    'Crypt::GCrypt'   => sub { $gcry->encrypt($plaintext); },
  };

$cbc->finish;
$gcry->finish;
__END__
                  Rate      Crypt::CBC Crypt::Rijndael   Crypt::GCrypt
Crypt::CBC      74.2/s              --            -83%            -89%
Crypt::Rijndael  430/s            479%              --            -39%
Crypt::GCrypt    704/s            849%             64%              --

[download]

Upd: fix to improve Crypt::CBC performance

In reply to Re^3: Encrypting a Message in C# with Rijndael and Decrypting it on Perl by zwon
in thread Encrypting a Message in C# with Rijndael and Decrypting it on Perl by zeussn

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