Question

I want to use AES encryption with ISO9797 M2 Padding . But in not under java by standard padding modes Cipher Algorithm Padding
How to implement ..?

Thank’s

Answer 1

If it is not available in standard Java, then you could implement it yourself, and add the appropriate bytes to the end of your plaintext. Then encrypt using NoPadding so you don’t get extra padding added. Decrypt using NoPadding again, and then remove the padding yourself.

The padding scheme is very simple to implement:

add an 0x80 byte
while not at block boundary
  add an 0x00 byte
endwhile

I had a quick look at the Bouncy Castle library, and that does not appear to have ISO 9797 either.