Is it possible to access BitLocker encrypted external hard drives from other platforms, like Windows Mobile, Android, Surface, Linux, Mac OS X?
The answer is : it depends, because you mention Bitlocker which is not always what's used on external hard drive.
Two different formats
First, it seems that:
- On "internal" storage (connected via SATA or actually external via eSATA), Windows installs "Bitlocker". On a per-partition basis this creates encrypted partitions (not encrypted files on a normal partition).
- On "external" storage (connected via USB, whatever it actually is, e.g. a SATA hard drive), Windows installs "Bitlocker To Go". In an otherwise normal volume (e.g. plain FAT32), this creates hundreds of small files (many empty) and a big file taking all space, which contains actual encrypted data, including executable files to enable data access on some Windows versions only.
Since Windows expects one format or the other depending on how the device is plugged (say, the same SATA drive through USB or eSATA cable yield different expectations), switching back and forth causes problems on Windows (like: you can't access your data because Windows expects the other format). See for example Access BitLocker Encrypted Drive Externally - Microsoft Community and windows - Bitlocker-To-Go on fixed drive - Super User.
Now, back to the multi-platform question.
Access Bitlocker partition on other platform: yes on Linux, probably yes on others
There is a GPL-licensed software that can read a Bitlocker device through Linux FUSE or just make a decrypted copy of the volume. The FUSE mode is probably Linux-specific, but the "decrypt to a copy" mode may be more portable.
The software is named Dislocker. From its README:
This software has been designed to read BitLocker encrypted partitions under a Linux system. The driver used to only read volumes encrypted under a Windows 7 system but is now Windows Vista capable and has the write functionality.
The driver can run into two different modes : with or without FUSE. This mode is decided at compilation time within the Makefile.
With FUSE, you have to give the program a mount point. Once keys are decrypted, a file named `dislocker-file' appears into this provided mount point. This file is a virtual NTFS partition, so you can mount it as any NTFS partition and then read from it or write to it.
Without FUSE, you have to give a file name where the BitLocker encrypted partition will be decrypted. This may take a long time, depending on the size of the encrypted partition. But afterward, once the partition is decrypted, the access to the NTFS partition will be faster. Another thing to think about is the size on your disk this method need (same size as the volume you're trying to decrypt). Nethertheless, once the partition is decrypted, you can mount your file as any NTFS partition.
Access Bitlocker To Go volume on other platforms: not so far ?
This is the case I was faced with, and noted that Dislocker could not deal with it. Reading source code, it is written to assume an encrypted Bitlocker partition, not a volume filled with Bitlocker To Go files.
In this case, the answer seems "no". Your best bet is probably to use a Windows machine to access files or create a virtual machine inside a non-Windows host.
What I did is explain the case to the person that came with the encrypted USB stick. Encryption was overkill in this case, just "company policy" had all Windows machine automatically turn any inserted USB stick into an encrypted one. The file we needed was actually not sensitive at all so he went back to his office and sent it to me via e-mail. Also, the file was a Microsoft Office file which is another matter. We finally had the job done anyway. :-)
The answer is "No, you won't be able to access a disk encrypted by Bitlocker on other OS than Windows7 and up". Why? This is speculative and can't be answered for sure, a quick shot is just "why should Microsoft support other OS for something that is usually bound to the machine itself?".
An alternative for multiplatform is http://www.truecrypt.org/
No, BitLocker is supported only by Microsoft Windows operating systems, excluding Windows Mobile and older than Windows Vista OS.
Why no? Because Microsoft always wanted to create their own technologies and products. That's the essence of business, not just something that only Microsoft would do. Businesses not only create new products, but also try to create better products (make competition for others) and they also try to create products which would improve their current products. If they create something better than there already exists in the market, they get some share of it. But as for BitLocker, I believe that the best explanation is BUNDLING (microeconomics/marketing term). They offer products such as BitLocker with Windows OS or MS Outlook with MS Office for no additional cost for the producer (MS). The idea here is that by providing more services and more functions with same product (Windows), they become more competitive with their Windows OS and it also becomes relatively a better product. That's the microeconomics perspective.
Another big reason for using BitLocker is LEGAL: most other products would require users to agree with their license if not add additional cost for the manufacturer (i. e. while installing Windows you would have to accept to Windows EULA, but also to, for example, TrueCrypt license). Also, most licenses prohibit implementing them for commercial use, so it complicates things even more. In the end of the day, relaying on others' products is not good for the Microsoft's brand.
In conclusion, Microsoft created BitLocker purely for business reasons so not keep Microsoft Windows competitive. A perfect example would be Internet Explorer, which they created for the same reason, but recently have been punished (http://en.wikipedia.org/wiki/Product_bundling#United_States_v._Microsoft).
The only way you could access those encrypted drives is by sharing them via SMB/CIFS (implemented as "file sharing services" in Windows) or other file sharing protocols (FTP, HTTP, etc.).