Singapore-based startup iTwin has been offering their secure solution for cloud computing for over a year now, but with their recently-added Mac support, they might just become a real contender in the file-sharing space. The company's eponymous flagship product consists of a Janus-like USB drive that acts as a physical key to unlock digital files: once the device has been set up, a second user takes half of the key—something like those kitschy broken heart necklaces—in order to access the files remotely, via cloud. The hardware itself contains the security, including Advanced Encryption Standard (AES) 256 bit encryption and the ability to disable access via web, among other features.

Essentially, iTwin offers Dropbox- (or AirDrop-) style cloud computing with a pocketable security barrier in the form of the USB key... and without the fees attached to it.

Remotely edit shared files

Remotely edit any shared file from any location. iTwin allows you to keep a single version on one computer, with you and your chosen iTwin partner collaborating directly on this version. Say goodbye to multiple versions of files flying around by email. Say goodbye to the headaches of needless re-work. Say hello to iTwin.

One-time cost. No fees, ever

Don't pay for cloud storage. Don't pay subscription fees for file access. Don't get locked in. You have all the storage you need on your computer and home hard drive. With iTwin, share it and access it from anywhere. Create your own personal cloud. Secured by hardware-grade encryption.They've produced a video to announce Mac support:

Of course, connectivity come down to the ISP—"As long as iTwin is plugged into two computers which have Internet connection, iTwin allows computer to computer file transfer anywhere on Earth"—though the transfer software has a built-in pause feature in case of network interruptions.