Android AES-128 encryption/decryption of file is very slow. How can I increase the speed

Question

I am developing an android app that secures images and videos like Vaulty and Keep safe. I am trying to use AES-128 encryption/decryption technique to store images and videos. I

Answer 1

One thing that is making your code run slow is the size of your buffer:

byte[] d = new byte[8];

You should bump it up by a few orders of magnitude if you want it to run fast. Given the size of your files I would suggest using at least 1 MB but nowadays you can realistically set it to a few MBs, even on Android. Try changing it to:

byte[] d = new byte[1024 * 1024];

and let us know how much did that improve the speed by.

Answer 2

Use a larger buffer as suggested by @MikeLaren, and also wrap the FileOutputStream in a BufferedOutputStream. When decrypting, wrap the FileInputStream in a BufferedInputStream. Or do both in both cases: no harm done.

No need for heroic buffer sizes like a megabyte: 8k or 32k is sufficient.