If you are very concerned about security on your iOS device, now you have a new jailbreak tweak called Crypto that allows you to quickly and easily encrypt any text, making it impossible for anyone without a password to read your text.
The tweak basically algorithm uses a 256 - bit encryption that only someone who uses Crypto can read.
This not only keeps the information on your own device safe from anyone, and you can also send your ciphertext to another person through Facebook Messenger, iMessage, WhatsApp, or any other app and the other user can unlock the message if Crypto also used.
If you send the text to someone who does not have the tweak installed, you will not be able to unlock the text.
When you want to encrypt a text, all you have to do is select all and then click on the action menu until you see the encryption button (Crypt).
As you can see in the picture above, the selected text has become a random bunch of numbers, symbol and letters.
To decode the text that has been encrypted by Crypto, you must reselect the text, click on the menu action again until you see the decrypt button, then to tap into it. You will be prompted to enter your password Crypto to see the text. When you do, click "OK".
Having deciphered the text, it is again legible for reading.
To use the tweak, you need a password. Fortunately, this is all you have to configure Crypto. Once you already have configured your key, you will use it to decrypt any ciphertext.
Crypto is available in the repository BigBoss Cydia for $ 1.99 and works with all devices with iOS jailbroken 9.