If you use Blowfish directly you must also remember to supply data in the 8 byte chunks it wants. Here is another example of a working implementation:

# First encode $f2 into $f1 Encode data
my $cipher =  new Crypt::Blowfish $model_passphrase;

# Pad $f1 to the next 8 byte boundary
if((length($f2) % 8) != 0)
  {
    $f2 .= "\x00" x (8 - (length($f2) % 8));
  }

for(my $i=0;8*$i<length($f2);$i++)
  {
    $f1 .= $cipher->encrypt(substr($f2,8*$i,8));
  }

# Since we have to work on Windows don't forget
# the binmode() on the file handle

# Now to decode $f1 into $f2
if((length($f1) % 8) != 0)
  {
    $f1 .= "\x00" x (8 - (length($f1) % 8));
  }

my $cipher =  new Crypt::Blowfish $model_passphrase;
for(my $i=0;(8*$i)<length($f1);$i++)
  {
    $f2 .= $cipher->decrypt(substr($f1,8*$i,8));
  }
$f2 =~ s/\x00+$//s;
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