Crypdroid

Crypdroid allows you to safely encrypt your private texts and files.
The encrypted data can then be sent via e-mail, WhatsApp or SMS or can be stored in your DropBox. The possibilities vary depending on your installed apps.
Crypdroid allows you to not only exchange encrypted texts and files between different Android devices but also to securely communicate with a PC. This is enabled through the free open-source software CrypTool 2. Texts can be encrypted and decrypted between Crypdroid and the Cryptool 2 tool "encrypt with password".

Your data is encrypted with the cryptographic algorithm AES-256. The session key that is used for encryption is derived from your password via the PKCS#5 standard. These algorithms provide a good balance between security and performance.

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Do you have an idea on how to improve Crypdroid or do you want to lend a hand in the further development of Crypdroid? Or do you want to be sure that Crypdroid does securely protect your personal data?
Since Crypdroid is open source you can do all that. The source code is published on github.com