https://devzone.nordicsemi.com/f/nordic-q-a/16196/do-i-need-checksum-to-ensure-my-data-is-intactI am sending and receiving streams of data over BLE. Do I need to add a checksum byte for every GATT write/notification/indication to ensure that my data is not corrupt during BLE data transfer? Or is there already some lower layer system to ensureen-USTelligent Community 13Mon, 05 Sep 2016 14:25:51 GMThttps://devzone.nordicsemi.com/thread/61836?ContentTypeID=1Mon, 05 Sep 2016 14:25:51 GMT137ad170-7792-4731-bb38-c0d22fbe4515:fc2d21ed-269d-4bd9-b9b1-587650136a2cUlrich Myhre<p>To expand on this, every packet contains a CRC field to verify data consistency. CRCs are very sensitive to single bit flips, but there is of course a possibility that your corrupted transmission ends up having the same CRC. Every data packet is also whitened before going through the air, as to reduce the risk even further. De-whitening and removal of CRC happens long before you receive the packet, so you do not see this.</p> <p>In addition to this, encrypted connections also contain a Message Integrity Check (MIC). This uses the IETF RFC 3610 algorithm with AES-128 (NIST FIPS-197) to create a 4 byte field for message authentication. If, by chance, a corrupted message passes CRC, the MIC check will likely fail and disconnect the link before anything is given to the application.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/61835?ContentTypeID=1Mon, 05 Sep 2016 12:13:31 GMT137ad170-7792-4731-bb38-c0d22fbe4515:7515e4ee-3316-4dea-9abd-3aef8929b86aRK<p>Every btle packet already contains a checksum. So the data is already protected. Of course checksums are not foolproof but you probably don&#39;t need to add more.</p><div style="clear:both;"></div>