Home » IT Services News » IT Services News No. 159. September-October 2012 » From the Helpdesk... Encrypt Your Files in Cloud Storage

From the Helpdesk... Encrypt Your Files in Cloud Storage

Cloud Security

Online cloud storage services, such as Dropbox, Google Drive and SkyDrive, are gaining popularity for storing and syncing files between multiple devices. Providers of such services are offering their users with 2GB or more free storage.  Users can sync their files between multiple devices, regardless whether they are running Windows, Mac, iPhone, iPad or Android. Online cloud storage providers claim that files are encrypted in transmission between users’ devices and their cloud servers. However, anyone that gets unauthorized access to an account can access all files in the account, some of which may contain sensitive information.

In June 2011, Dropbox identified a software bug which had allowed unauthorized access to users’ accounts and files without authentication.  For a period of approximately four hours, anyone could log onto any account and access files in the account without password.  This security incident was reported in the article Dropbox leaves user accounts unlocked for 4 hours.   So, storing your files in online cloud storage is not as secure as you wish it to be.


Encypt Your Files

To protect your files in online cloud storage, you may want to consider using one of the following two encryption programs to encrypt your files containing sensitive information.

  • Sophos Free Encryption is a file encryption program which supports 256-bit key Advanced Encryption Standard (AES) encryption.  With Sophos Free Encryption, you can encrypt files with password protection and save it to online cloud storage.  No one can read the files without your password.  

    Figure 1: Encrypt a file with password using Sophos Free Encryption.

  • BoxCryptor: Boxcryptor is a 256-bit key AES encryption software for cloud storage including Dropbox, Google Drive and SkyDrive. Boxcryptor is a virtual hard disk which helps you to secure sensitive files on your cloud storage. When saving files to the virtual hard disk, Boxcryptor encrypts the files on-the-fly and stores the encrypted file in a encrypted folder e.g. a folder that is synced to the cloud storage like a Dropbox folder. When accessing the files, Boxcryptor will decrypt the files in real-them, making the files available as any other item.

    Figure 2: Boxcryptor provides 256-bit key AES encryption for cloud storage including Dropbox, Google Drive and SkyDrive.


Agnes Chau
Tel: 3549 5707
Email: achau@hku.hk