ParaCryptor

Introduction 

Many Android users download low quality soft to hide their documents. All it does is conceal them from the desktop, but they are easily accessible through a PC. ParaCryptor uses AES with CBC key to code your documents, the most convenient and reliable method to ensure the safety of your files. 

Features 

The way AES crypt through a 256 bit CBC key works is by dividing the file in question into numerous small blocks. The first is coded randomly becoming the key to crypt the next block and so on. This means every file block receives a unique crypt key that is next to impossible to figure out. The utility can crypt almost all kinds of files like that. All you need is to choose the file file and think of a password to it. In a few seconds after that, the files will be encrypted and the original erased. There is also the additional option of wiping docs after the screen lock which could come in handy when in urgent need of document security. 

Bottom Line 

All documents deleted through ParaCryptor are wiped clean by zeros, so it is impossible to return them even through specialized software.