PDA

View Full Version : How to encrypt files to be shared on Dropbox?



Andreapa
05-28-2015,
I frequently need to share files on Dropbox. These files often contain personal and private information. I would like to encrypt the files, but I do not want to burden the recipients by requiring that they install special software to be able to decrypt them.

My solution to date has been to put all of the files into an encrypted ZIP file. This works. Most people have an unzip program. The downside is that it is a hassle to add or remove files. The entire zip file, which can be quite large, must be replaced.

Is there a tool I can use to encrypt individual files that can easily be decrypted by anyone (on any system) who has the pass code?

Thanks

Andrescelo
05-29-2015,
Elsewhere, another tech indicated: one cannot encrpyt a file on C, send to Dropbox, with said file staying encrypted. Somehow, the encryption is lost during the transfer [copy operation]. I've never used either encryption or dropbox, so I do not know if that tech's info applies to what you're wanting to do.

AndreaTevy
05-29-2015,
I would use 7z, There is a download link for it on bleepingcomputer's downloads section, but it would need the other person to run 7z as well. Fortunately 7z is a pretty common program, sometimes it even comes bundled on computers which are new, but it isn't a standard built in function of most operating systems (windows cannot deal with 7z files itself, some linux types might be able to) so for those who haven't installed 7z themselves for some reason in the past they would need to install it before they could opne the encrypted files. One good thing is that being available on this site there is a safe download link you can provide to those people who don't have 7z already. 7z, atleast the version I use (same version as is available athttp://www.bleepingcomputer.com/download/7-zip-for-windows/ ), can also make self-extracting archives. But there are issues with these. Self-extracting archives are exe files, and if a user is cautious about installing 7z you can be sure they won't feel safe in running an exe file you just sent them.


7z won't free you of the compressing/extracting requirement, it is just like zip files for this, but a bit faster. 7z does however offer more powerful encryption (the type used as standard on zip files is apparently not that strong, whereas 7z uses AES 256) and will allow anyone to encrypt and decrypt files. On the latest versions of windows the built-in zip file processing systems let anyone open zip files if they have the password, but only users of particular (pro and enterprise I think) windows versions can make encrypted archives. With 7z anyone with it installed can make encrypted archives, anyone with 7z installed can open them with the password.

7z archives (especially if you first put the secret files into an ordinary zip file, then put this zip file into an encrypted 7z archive) also give greater protection to information such as the file names, there is an option during encryption to encrypt these so they cannot be seen without entering the password. If you put the secret files in a zip file and then the zip file into a 7z then eavesdroppers couldn't see the individual file sizes either (they might be able to see that the 7z archive held a zip file called secret-files.zip which was a particular number of megabytes in size, but they wouldn't know whether the zip file had one big file, many little ones or a mixture, and they wouldn't know the names of the files within it).

Andrewbax
05-30-2015,
RolandJS, on 09 May 2015 - 12:26 AM, said:http://www.bleepingcomputer.com/forums/public/style_images/master/snapback.png (http://www.bleepingcomputer.com/forums/index.php?app=forums&module=forums&section=findpost&pid=3701342)

Elsewhere, another tech indicated: one cannot encrpyt a file on C, send to Dropbox, with said file staying encrypted. Somehow, the encryption is lost during the transfer [copy operation]. I've never used either encryption or dropbox, so I do not know if that tech's info applies to what you're wanting to do.

As I said above, I upload encrypted ZIP files all the time. None of them have ever "lost" their encryption.

If you think about it, this makes no sense. If an encrypted file could be decrypted simply by uploading it to Dropbox, encryption wouldn't be worth much, would it?

AndrewHige
05-31-2015,
Guys, I have no worries or concerns http://www.bleepingcomputer.com/forums/public/style_emoticons/default/smile.png I was simply passing on what another tech elsewhere said about sending single encripted files such as TXTs, DOCs, etc., [not using any zip program] up into Dropbox. Elsewhere that OP mentioned any single file sent to Dropbox became readable in a viewer or MS Explorer PreView Panel, even though encrypted. Again, I have no worries or concerns; I use 7zip, making passworded and unpassworded zip files all the time. http://www.bleepingcomputer.com/forums/public/style_emoticons/default/smile.png

AndrewDito
06-01-2015,
RolandJS, on 09 May 2015 - 8:52 PM, said:http://www.bleepingcomputer.com/forums/public/style_images/master/snapback.png (http://www.bleepingcomputer.com/forums/index.php?app=forums&module=forums&section=findpost&pid=3701967)

Guys, I have no worries or concerns http://www.bleepingcomputer.com/forums/public/style_emoticons/default/smile.png I was simply passing on what another tech elsewhere said about sending single encripted files such as TXTs, DOCs, etc., [not using any zip program] up into Dropbox. Elsewhere that OP mentioned any single file sent to Dropbox became readable in a viewer or MS Explorer PreView Panel, even though encrypted. Again, I have no worries or concerns; I use 7zip, making passworded and unpassworded zip files all the time. http://www.bleepingcomputer.com/forums/public/style_emoticons/default/smile.png

I would be very interested to know if this is true and, if so, how it works. Maybe you can invite him to come here and enlighted us (me).