Lots off stuff to pass along about this. I'm on BlackBerry 6, but what I write here will probably coincide with your OS7 Bold. If not, hopefully somebody else will point out what's different.
Originally Posted by jinxednuance
To make it so others can't access the data you have on your micro sd card, in addition to setting a strong password, you'll need to turn on Encryption.
Go to Options>Security>Encryption. I'll skip over Device Memory Encryption for now, because that's a separate lesson, but you should encrypt that, too.
In the part for Media Card Encryption, put a check in the "Encrypt" box. Put a check in the "Include Media Files" box.
Then, it's time to select the mode. There are three: "Device Key," "Device Password," and "Device Password & Device Key." Which mode to use is an important decision. I'll explain why.
"Device Password" is the only mode that will allow you to decrypt your media card's encrypted files in a different BlackBerry (so long as you remember the password). It's a good setting, but there's a drawback: someone who wants to crack your BlackBerry's password can use special software to launch an attack against your media card and extrapolate the password. For average users, this probably isn't a major concern. It's unlikely that the opportunistic thief or finder of a Blackberry would bother doing this. But if you're worried that someone is after your data, don't use this mode.
The other two modes, "Device Key" and "Device Password & Device Key" are not vulnerable to this kind of attack, but if you use either of them, you won't be able to transfer the media card to a different Blackberry and decrypt the files nor will you be able to decrypt your files if your BlackBerry undergoes a security wipe. So, these modes offer superior security and protection, but don't use them if your files are important to you and you haven't backed them up elsewhere like on your computer. I use "Device Password & Device Key," but my encrypted media card files are also backed up on my password locked ThinkPad's hard drive.
There's more. There's the matter of which files are encrypted and how to transfer encrypted files between your Blackberry and your PC. Not all files are automatically encrypted. If encryption is properly on, files you receive over the air (network, wifi, or Bluetooth) and store on your media card will be automatically encrypted. Files you transfer from your pc to your BlackBerry by plugging in to the USB port will only be encrypted if you use the "Files" feature of BlackBerry Desktop Software Version 6. To use this feature, plug in your BlackBerry and select "Charge Only." Then open Desktop Software. When prompted by Desktop Software, enter your BlackBerry's password. Once it finishes loading, click on the "Files" tab on the left hand side. A window will open in Desktop Software which resembles an explorer window. You can now open other windows on your PC, find the files you want to transfer to your media card, and drag and drop them to Desktop Software's "explorer" window. You can even drag and drop entire folders or you can create folders in the Desktop Software "explorer" window itself. You can do the same thing, in reverse, and move encrypted files from your Blackberry back to your PC. But if you don't use Desktop Software's "Files" feature, and instead of choosing "Charge Only" choose "USB" when you plug in your BlackBerry, any files you move back and forth between your PC and BlackBerry will remain in whatever form they are in; encrypted will stay encrypted, unencrypted will stay unencrypted.
Here's what I do when I get a new micro sd card, as an example. I have a bunch of pictures and videos that I want to be able to view on my BlackBerry. Half of them I want encrypted (personal stuff) and half of them I don't care (wallpapers, etc). Using Desktop Software's "Files" feature, I transfer everything I want encrypted to my BlackBerry's micro sd. Using the USB feature (it's a bit faster), I transfer the stuff I won't bother to encrypt. I also store other things I can't view on my BlackBerry on my micro sd card. I encrypt that stuff using another program on my computer and transfer it to my micro sd card using the USB feature or by putting the card directly in my ThinkPad's card reader.
Encrypted files will have a .rem extension, for example, jpg.rem. Remember to back up all your data elsewhere.