Crypdroid encrypts messages with AES and encodes the ciphertext in a way that it could be sent as a normal text message. It is compatible with the dedicated tool within CT2.
Are native apps more beautiful and faster?
For android there is a native app for encryption which is available for free named "Crypdroid" within the Play-Store. Crypdroid can encrypt messages to any app on the smartphone or save it as a file. Because of the transformation into printable characters a message can be send inconspicuous e.g. as normal email-text or text message (SMS). The receiver can than decrypt the message either through an own installation of Crypdroid on his/her smartphone or on the PC with CrypTool 2. This is possible due to the interoperability of Crypdroid an its tool "Encrypt with Password" from CrypTool 2. With this tool also the answer can be encrypted and send back.