It's really common in Android (10-20% of apps), but happens occasionally in iOS too. The most common Android obfuscator is Proguard, but we also see Codeguard

It's really common in Android (10-20% of apps), but happens occasionally in iOS too. The most common Android obfuscator is Proguard, but we also see Codeguard and others. The most surprising thing we found is that many developers build their own custom obfuscator. I think it's because they're trying to keep people from ripping off their code or hide secrets on the client side. Because Android allows a variety of techniques (custom classloaders, native code extensions that can overwrite their own code), there's a proliferation of methods there. In iOS, it's less common. You'll see a few frameworks like RNCryptor used to hide client-side secrets. Some apps use UAObfuscatedString to try to hide class names and selectors, but our similarity algorithms are based on a number of independent program features, including control-flow graph structure, which are unaffected by this. There are obfuscating compilers too, but it's very rare for anyone to use them.