I decided to use a different target platform for my project. Initially, I was using Android Kitkat + Galaxy Nexus (ARMv7 + TI OMAP 4460). To obtain best performance with some crypto operations, I am now using Android Lollipop + Nexus 9 (ARMv8 64bits). I did some tests with basic OpenSSL examples (for example, AES-128 and SHA1) and the numbers are impressive.