First, could you confirm that you really need to ability to append record to an existing encrypted file?

Using my appendable format (which means you undid the Base64 encoding before storing the data):

utf8::decode( my $s = $cipher->decrypt( read_str($fh) ) );
[download]

Using my appendable format, but left the data Base64-endoded:

utf8::decode( my $s = $cipher->decrypt( decode_base64 ( read_str($fh) 
+) ) );
[download]

If you just dumped the return value of your encrypter to a file:

local $/;
utf8::decode( my $s = $cipher->decrypt( decode_base64 ( <$fh> ) ) );
[download]

Thank you for your help.

First, could you confirm that you really need to ability to append record to an existing encrypted file? If I understand the question correctly; not always, but maybe at times and therefore I have to code that in.

I still cannot get it to decrypt the file that is encrypted using BlowfishNET 2.1.2. Here is the code that includes your most recent updates as well. Pardon the long variable names.

sub encryptData {
    my ( $cObject ) = @_;
    my $buffer;

    open(PLAINTEXT, "<", $plaintextReadFileName) || die("Cannot open f
+ile $plaintextReadFileName");
    binmode PLAINTEXT;
    flock PLAINTEXT, LOCK_SH;

    open(my $fhENCRYPTEDFILE, ">", $encryptedFileName) || die("Cannot 
+open file $encryptedFileName");
    binmode $fhENCRYPTEDFILE;
    flock $fhENCRYPTEDFILE, LOCK_EX;

    while (read(PLAINTEXT,$buffer,4)) {
        utf8::encode($buffer) if ($type eq "utf8base64");
        $buffer = $cObject->encrypt($buffer);
        print $fhENCRYPTEDFILE (pack('N', length($buffer)), $buffer);
    }
    close PLAINTEXT;
    close $fhENCRYPTEDFILE;

    print "Encrypted $plaintextReadFileName to $encryptedFileName.";
}

sub encodeData {
    open(my $fhENCRYPTEDFILE, "<", $encryptedFileName) || die("Cannot 
+open file $encryptedFileName");
    binmode $fhENCRYPTEDFILE;
    flock $fhENCRYPTEDFILE, LOCK_EX;

    open(my $fhENCODEDnENCRYPTEDFILE, ">", $encodedFileName) || die("C
+annot open file $encodedFileName");
    binmode $fhENCODEDnENCRYPTEDFILE;
    flock $fhENCODEDnENCRYPTEDFILE, LOCK_EX;

    if ($type eq "utf8base64") {
        $utf8base64EncryptedFile = do { local( $/ ) ; <$fhENCRYPTEDFIL
+E> } ;
        print $fhENCODEDnENCRYPTEDFILE encode_base64($utf8base64Encryp
+tedFile);
    }

    close $fhENCRYPTEDFILE;
    close $fhENCODEDnENCRYPTEDFILE;

    print "Encoded $encryptedFileName to $encodedFileName.";
}

sub decodeData {
    open(my $fhENCODEDFILE, "<", $encodedFileName) || die("Cannot open
+ file $encodedFileName");
    binmode $fhENCODEDFILE;
    flock $fhENCODEDFILE, LOCK_EX;

    open(my $fhDECODEDFILE, ">", $decodedFileName) || die("Cannot open
+ file $decodedFileName");
    binmode $fhDECODEDFILE;
    flock $fhDECODEDFILE, LOCK_EX;

    $utf8base64EncodedFile = do { local( $/ ) ; <$fhENCODEDFILE> } ;
    print $fhDECODEDFILE decode_base64($utf8base64EncodedFile);

    close $fhENCODEDFILE;
    close $fhDECODEDFILE;

    print "Decoded $encodedFileName to $decodedFileName.";
}

sub decryptData {
    my $cObject = shift;
    my ( $length, $buffer );

    open( my $fhREADFROM, "<", $decodedFileName ) || die("Cannot open 
+encrypted file $decodedFileName");
    binmode $fhREADFROM;
    flock $fhREADFROM, LOCK_SH;

    open( finalFile, ">", $decryptedFileName ) || die("Cannot open fil
+e $decryptedFileName to write decrypted contents");
    binmode finalFile;
    flock finalFile, LOCK_EX;

    while (!eof($fhREADFROM)) {
        $length = unpack('N', read_bytes($fhREADFROM, 4));
        $buffer = read_bytes($fhREADFROM, $length);
        utf8::decode( my $str = $cObject->decrypt( $buffer ) );
        print finalFile $str;
    }

    close $fhREADFROM;
    close finalFile;
    print "Decrypted $decodedFileName to $decryptedFileName.";
}

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;
}

encryptData($cObject);
encodeData() if ($type eq "utf8base64");
decodeData() if ($type eq "utf8base64");
decryptData($cObject);
[download]

Just to clarify; the encrypt, encode, decode and decrypt functions do work if I do all the encryption, encoding, decoding and decryption on my end. However, I can't get it to decrypt the file that is encrypted using the BlowfishNET 2.1.2 library from http://www.hotpixel.net/software.html using the BlowfishSimple class. I'll paste the README here again:

"For efficiency the given string will be UTF-8 encoded and padded to the next 8byte block border. The CBC IV plus the encrypted data will then be BASE64 encoded and returned as the final encryption result."

I am confused and hope you can clarify.

I assume encryption is performed in the following order based upon what the README for the BlowfishNET 2.1.2 library says:

• UTF-8 encoded
• Encrypted
• Padded to next 8-byte block border
• BASE64 encoded (slurping)

Now, while decrypting, I was trying to go in the following order:

• BASE64 decoded (slurping)
• Unpack next 8-byte block border
• Decrypt
• UTF8 decoded

What am I missing here? Am I not using unpack correctly for my purpose? Could you please help me understand the following line: $length = unpack('N', read_bytes($fhREADFROM, 4)); What would the value of $buf be in the call to read_bytes here? Thanks again for your help.

First, could you confirm that you really need to ability to append record to an existing encrypted file?

If I understand the question correctly; not always, but maybe at times and therefore I have to code that in.

Sounds like you don't need the code from this thread at all, and I'm curious as to why you posted in this thread at all. Your problem has nothing to do with the OP's.

(If you ever do need to append to a file, just decrypt it, append, and encrypt the new contents.)

Even if you will be using this for log files where the append code would be useful, you should be concentrating on being able to decrypt the code from BlowfishNET. One problem at a time.

However, I can't get it to decrypt the file that is encrypted using the BlowfishNET 2.1.2

I don't feel like installing this, so I'll need the following:

• A runnable program that consists of your attempt at decrypting BlowfishNET files (and nothing else).
• A message encrypted using BlowfishNET.
• The key with which the message was encrypted.