The Mexican Army Cipher Disk was used during the time of conflict between Mexico and the USA shortly before World War I. You can turn the disks individually (or not). You can lock screen orientation and turn on vibrations. You can cipher and decipher a message and display the frequency analysis for each disk. You can break a message searching some keywords.
Nicolas BERNE is the creator of the app that is included in the Educational category. The developer released a new version of the tool on Feb 24, 2018 and over 5K users downloaded and set up Mexican Army Cipher Disk. This application has the overall rating 4.7 on Google Play.
You can get the installation package of Mexican Army Cipher Disk 1.50 for free and take a look at users' reviews on Droid Informer. The app works fine on Android 4.0 and above. It's secure to download the app.