android java.lang.NoClassDefFoundError: org.bouncycastle.crypto.engines.AESEngine api 16 : <p>I am using <code>com.nimbusds.jose.crypto</code> library in my android client for doing some jwt stuff. </p>

<p>This is what i declare in my gradle file : </p>

<pre><code>    compile 'com.nimbusds:nimbus-jose-jwt:4.23'
</code></pre>

<p>Everything works fine on api >=19, but when I am running the code on api 16, I am getting this exception : </p>

<p><code>java.lang.NoClassDefFoundError:  org.bouncycastle.crypto.engines.AESEngine</code>. </p>

<p>What's the issue here? Why is the class <code>AESENGINE</code> not available on api 16?</p>
