Encryption + Dropbox + Android

Dec 24, 2011
Dropbox is a great application which syncs data across different computers and devices. This makes Dropbox ideal for syncing important, & often sensitive, information across devices. Saving sensitive information on cloud makes me feel uncomfortable and cranky. This is log of softwares/apps required for encrypting data. Explicit goals are:
  1. Data should never be saved to disk unencrypted.
  2. Encrypted data should be readable, even without internet access, on Windows, Linux, & Android devices.
  3. Encryption algorithm should be well known standard algorithm. Open source programs are preferable.
Following are some of the possible solutions with some notes. Not all of them achieve all the goals mentioned above.

EncFS provides encrypted filesystem in user space. It allows mounting an encrypted folder to a user defined location. Cryptonite is an android app which supports mounting of encrypted EncFS. Unfortunately, I found Cryponite to be buggy and the android app did not work out well for me. EncFS is definitely among perfect solutions for "desktop-only" systems.

BoxCryptor comes very close (and probably is heavily inspired by EncFS). It has been developed with tight integration with dropbox. It uses very popular AES-256 standard. Unfortunately its Android app requires internet connection to read the encrypted folder. Another drawback is the tight integration with dropbox. The Android app requires dropbox credentials to access data. I feel uncomfortable to give the dropbox credentials to any place other than dropbox itself.

enotes is the perfect solution for individual text files. So, each encrypted file is an independent text file and hence each individual file has to be encrypted/decrypted seperately. This can be advantage or disadvantage depending on the purpose. It also has an Android app: Encrypted Notepad. It uses AES-128 encryption and is good enough for me. The software is written in Java and hence is cross platform. Similar apps: Secret safe Lite, NoteCipher, OpenNoteSecure.

APG is an Android app which aims to provide a OpenPGP implementation. It uses public-private key or pass-phrase for encryption. But it saves unencrypted data to disk. Another app Encryption Manager Lite works in very similar fashion but with AES encryption. Similar apps: File Encrypter, Pattern Encrypt (Cool idea to use patterns for passwords).

PS: There are numerous desktop applications which can be used to encrypt/decrypt data using standard algorithms like AES. When accessing files on android device is not an issue, then any of these can be a solution. TrueCrypt is worth a mention in this category for its simple interface and powerful features. EncFS, as mentioned above, may also be suitable for some systems.