Is there an easy/straightforward way to extend the file upload class to encrypt files that are being uploaded? Not just encrypting the filename, but rather the data in the file itself.
I'm using mcrypt for db encryption, and would prefer to use the same for file encryption.
Looking through the Upload.php library, I don't see an obvious place where the uploaded file is read which is where I assume I'd shim in the encryption.
Any help/advice would be appreciated.
edit:
What I'm thinking is that somewhere in do_upload() (I'm thinking file_temp) the file gets encrypted before being moved (not copied!) into its final destination. However, I don't see anywhere in Upload.php where the code is working with any of the files' data outside of filename, size, type, etc. Does this approach make sense?
Rather than encrypting just the upload, use HTTPS/SSL to encrypt the entire connection between the client and server.
I decided to forgo modifying the upload class. What I did was after the file was uploaded, open the file, encrypt it, and write it out again.
$f=file_get_contents(BASE_PATH.$fileFullPath) or die ('<script>window.parent.transUpdateFail(\'no gfc'.$fileFullPath.'\');</script>');
$encf=$this->encrypt->encode($f,$this->e_key) or die ('<script>window.parent.transUpdateFail(\'no encrypt\');</script>');
$nf=fopen(BASE_PATH.$fileFullPath,"r+") or die ('<script>window.parent.transUpdateFail(\'no open '.$fileFullPath.'\');</script>');
$fw=fwrite($nf,$encf) or die ('<script>window.parent.transUpdateFail(\'no fwrite\');</script>');
fclose($nf);
Related
I need to store encrypted files into GridFS using PHP.
So far I've found the following way:
Open the file (fopen)
Apply a encryption filter (stream_filter_append)
Write the encrypted data in a new temporary file (fwrite)
Use MongoGridFS::put() to store the encrypted file into GridFS.
Remove the temporary file
This approach as the inconvenient to go with a temporary file which can lead to a big lack of performance when dealing with huge files.
Is there any way to get a “writeable” stream in gridFS in order to merge step 3 and 4 of my above scenario and avoid the temporary file?
In another words, is there any equivalent to MongoGridFSFile::getResource but for “write” purpose?
I have mp3 players set up on my site to play mp3s. At the moment, users can easily look through the source, run a search for "mp3" and download all of the music on my site. I know it's virtually impossible to completely prevent a determined user from downloading the music but I want to make it harder for the average user. Is there any way I can obfuscate the links to the mp3s?
Relevant site: http://boyceavenue.com/music
You did not specify the language you are using. To expand upon what Marc B wrote, I would recommend using the PHP http_send_file command along with the checksum of the file.
To send the file, use the following:
$filename = "/absolute/or/relative/path/to/file.ext";
$mime_type = "audio/mpeg"; // See note below
http_send_content_disposition($filename, true);
http_send_content_type($mime_type);
http_throttle(0.1, 2048);
http_send_file($filename);
If you are serving up multiple types of files using PHP 5.3.0 or later, you could determine the mimetype this way:
$filename = "/absolute/or/relative/path/to/file.ext";
$finfo = finfo_open(FILEINFO_MIME_TYPE);
$mime_type = finfo_file($finfo, $filename);
finfo_close($finfo);
Calculating the checksum is simple enough. Just use md5_file.
So, what can you do with the checksum?
Well, you could create an array of checksums and filenames that cross-reference each other. That is, you include the checksum in the links to the file, but have a little routine that looks up the checksum and delivers the mp3 file. You also could do this in a database. You also could do like some apps that store files in a directory structure based on their checksums (music/3/3a/song.mp3 with a checksum of 3a62f6 or whatever).
If you don't care about the filenames being mangled, you could save the files with a checksum for the filename. That could be done at upload time (if your files are being uploaded) or through a batch script (using the CLI).
Another thing you should do is to put a default document (index.php or whatever) that tells people to look elsewhere. Also disable browsing the directory. If only a very small number of people will need access, you could also throw a password on the directory, thus requiring a login to access the files.
I am new to cryptography, hence I want to ask about my company's requirements.
We are using eToken with RSA support.
I have developed a code that encrypt file with public key and stored it in another file.
Now I want to pass the encrypted file to eToken, and here is my issue.
How can I access the eToken from a Java applet?
Is it right that I have to pass encrypted file to eToken and it will decrypt file for me?
How can I do this?
1.
I have created a audio player in silverlight.
within that player user is able to select a portion of song to save as ringtone.
but i got the time duration from .. but I have to cut the partial portion of stream or audio stream and save it to the server dick.
Plz suggest me how I can convert the selected audio time duration into the stream or byte array..?
-- Additional information on this question:
2.
I have created a ringtone audio player in silverlight. Within that user can select a portion which can be cut and save as a audio file.
I am unable to save the stream to the disk.. it is giving following errors:
Error 1. Attempt to access the method failed System IO FileInfo OpenWrite
Plz help
-- Additional information on this question:
3.
What are the use of MediaStreamSample & MediaStreamSource class in silverlight with respect to MediaElement?
Will it help in cutting a portion of audio file in order to create the ringtone out of a song?
If you need to save to the server, then you need to get that data to the server.
Just saving it (as answered) will try to save to the client's machine. What you need to do is upload the data to the server either via a WCF service or an ASHX handler or such. I've done something similar -- uploading MP3 files from a Silverlight client to a WCF service via a Stream, works well.
Next: You need to make sure that whatever splitting process you use accommodates the audio format-- ie you probably just can't split the binary file. What format are you using, mp3?
I've used something called mp3plt, before to split mp3s. You may be able to recompile the source into a Silverlight-compatible library, assuming it's written in something you can use, source here.
Or you can look into the mp3 specs to see if it is possible to just split the binary file, in which case taking the duration to cut (the one the user chose), and multiplying by the bitrate, (kb/s * seconds = kb) will give you the place in the file byte[] you can cut at.
Error 1. Attempt to access the method failed System IO FileInfo OpenWrit, you getting this error coz of security reasons. Before saving to disk you should promt SaveFileDialog to user, and then only save file to disk.
I'm writing an application with a dBASE database file in Borland Delphi 7.
Note: I think this question is file-security related and you can forget the dBASE thing (consider it as a TXT file) in this question.
The database must be accessed just by the application. Then it must be encrypted. Unfortunately dBASE doesn't support any password mechanism and i had to encrypt the file by myself (and i also HAVE to use dBASE)
What approach do you suggest to secure the database file?
The simple one is:
Encrypting the database file and placing it near beside the application EXE file.
When the application runs, it should decrypt the file (with a hard-coded password) and copy the result to a temporary file that has DeleteOnClose and NoSharingPermission flags.
When Closing, application should encrypt the temp dBASE file and replaces the old encrypted file with the new one.
I think this is a fair secure approach. But it have two big problems:
With an undelete tool the user can restore and access to the deleted temp file.
Worse: When application is running, if the system rebooted suddenly the DeleteOnClose flag fails and the temp file remains on hard disk and user can access it.
Is there any solution for, at least, the second part?
Is there any other solution?
You could also try to create a TrueCrypt file-based containter, mount it, and then put the dBase file inside the mounted encrypted volume. TrueCrypt is free (in both senses) and it's accessible via command line parameters from your application (mount before start, unmount before quit).
Depending on what you're doing with the database, you may be able to get away with just decrypting the records you actually need. For example, you could build indexes based on hash codes (rather than real data); this would reduce seeks into the database to a smaller set of data. Each record in the subset would have to be decrypted, but this could be a lot better than decrypting the entire database.