The InfoSec Institute article linked below discusses broken cryptography in Android applications. Broken cryptography attacks come into the picture when an app developer wants to take advantage of encryption in his application. This article covers the possible ways where vulnerabilities associated with broken cryptography may be introduced in Android apps and ways an attacker can exploit this kind of vulnerability.
Read the full article here – http://resources.infosecinstitute.com/android-hacking-security-part-16-broken-cryptography/