Update CipherInputStream to use AES instead

The RI won't use DES cipher anymore, so update to use AES so we can
continue to test.

Change-Id: Ib39b0c0653911ed675dc8b5b0120c66714d0f1fa
CipherInputStream: increase buffers for speed

This increases speed of CipherInputStreamBenchmark from 606ms to 28.5ms.

Bug: 12246774
Change-Id: If61c0a055fe1b8e87909711b15d0441fcdbe46c7