Are you sure the file was created using my write_str? The point of this thread was to create an appendable encrypted file format. I proposed such a file format, my encrypter produces it, and my decrypter decrypts it (and only it). 
>perl 700015.pl
Hello World
foo bar

>debug data.enc
-rcx
CX 0040
:
-d100 l40
0100  00 00 00 20 53 61 6C 74-65 64 5F 5F 90 66 5E D2 ... Salted__.f^.
      ^^^^^^^^^^^
0110  88 43 CE 87 E6 FE 44 DA-2C E8 84 FF 2B 2B A1 84 .C....D.,...++..
0120  FD BB 96 89 00 00 00 18-53 61 6C 74 65 64 5F 5F ........Salted__
                  ^^^^^^^^^^^
0130  1F 12 77 C8 38 9A 4B 69-A2 33 51 9D 03 60 50 27 ..w.8.Ki.3Q..`P'
-q

[download]

You seem to be missing the higlighted parts.

700015.pl: 

use strict;
use warnings;


use Crypt::CBC qw( );


my $qfn = 'data.enc';


sub read_bytes {
   my ($fh, $to_read) = @_;
   my $buf = '';
   while ($to_read) {
      my $bytes_read = read($fh, $buf, $to_read, length($buf));
      die("$!\n") if !defined($bytes_read);
      die("Unexpected end of file\n") if !$bytes_read;
      $to_read -= $bytes_read;
   }
   return $buf;
}

sub read_uint32 {
   my ($fh) = @_;
   return (unpack('N', read_bytes($fh, 4)));
}

sub read_str {
   my ($fh) = @_;
   my $length = read_uint32($fh);
   return read_bytes($fh, $length);
}

sub write_uint32 {
   my ($fh, $n) = @_;
   print $fh (pack('N', $n));
}

sub write_str {
   my ($fh, $str) = @_;
   print $fh (pack('N', length($str)), $str);
}


{
   my $key = Crypt::CBC->random_bytes(8);

   my $cipher = Crypt::CBC->new({ key => $key, cipher => 'Blowfish' })
+;

   {
      open(my $fh, '>', $qfn) or die;
      binmode($fh);
      write_str($fh, $cipher->encrypt("Hello World"));
      write_str($fh, $cipher->encrypt("foo bar"));
   }

   {
      open(my $fh, '<', $qfn) or die;
      binmode($fh);
      while (!eof($fh)) {
         print($cipher->decrypt(read_str($fh)), "\n");
      }
   }
}

[download]

(Blowfish was used since I'm having a linking problem with Rjindael. You should get similar results with both)

In reply to Re^5: line by line Encryption fun with Crypt::CBC and Rijndael? File Ownership issues? (code) by ikegami
in thread line by line Encryption fun with Crypt::CBC and Rijndael? File Ownership issues? by hmbscully

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