c# - How to add multiple bytes and get a byte array? -

given byte array

byte[] somebytes = { 0xff, 0xfe, 0xfe, 0xff, 0x11, 0x00 ,0x00 ,0x00 ,0x00} 

what's best add bytes? manually adding of bytes hand hex numbers yield 40b on above example preferably i'd end like:

byte[] bytesum = { 0x04, 0x0b } 

actually, need 0x0b part (used checksum). checksum calculated 0x0b xor 0x55 (which yields 0x5e) in case.

i understand isn't normal addition of bytes, how checksum calculated.

manually looping through byte array , adding them results in integer sum.

what's concise way of doing this?

erm,

byte checksum; foreach (var b in somebytes) {     checksum = (byte)((checksum + b) & 0xff); }