Simple Text Crypt
It's an Android app which encrypts plain texts. This app does not claim any permissions, so you can trust that it cannot send any of your private data to anyone.
Can You Trust it?
Messages produces by this app is secure and can be confidently send over a network, for example. It uses AES in CBC mode with PKCS5 padding for encryption, and uses PBKDF2 with HMAC, SHA1 and a random Salt in order to derive a secure key from the entered password. This is a very powerful encryption. Also it encrypts its settings before storing them on the device.
However, the app itself may not be very secure, and probably vulnerable to some attacks. Although it is secure enough to stand attacks from non-expert crackers, e.g. normal users, it should not be used for serious data encryption.
Why Should You Encrypt?
It's a big subject to discuss. I recommend reading these two articles:
Why do you need PGP? In this article, Phil Zimmermann compare encryption of emails to putting letters in an envelop: if you don't have anything to hide, why do you hide your messages in envelops?
Why we encrypt? This article tells us that we should encrypt everything not just to protect our privacy, but also to protect those activists which their lives are depend on encryption.
It is recommended to install the app from F-Droid.
Alternatively, you can download the apk directly from releases tab.
Copyright (c) 2015 Aidin Gharibnavaz
SimpleTextCrypt is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
SimpleTextCrypt is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with SimpleTextCrypt. If not, see https://www.gnu.org/licenses/.