The app was downloaded and installed by over 100K users and its latest stable update was on Jan 31, 2019. Take into account the important detail: ads are a part of Cryptography and it offers in-app purchases. Huawei and Samsung users recommend this application.
Get the installation package of Cryptography 1.7.1 that is completely free and have a look at users' reviews on Droid Informer. The app can be launched flawlessly on Android 4.1 and above.
As users see it, the app features such an advantage as a well-designed UI. As users indicate, the weak sides of this application are grammatical errors and many ads.