https://devzone.nordicsemi.com/f/nordic-q-a/20286/isn-t-csrk-related-to-encypt-data-bitsIs it just used to confirm that source(sender) of message is valid?en-USTelligent Community 13Mon, 20 Mar 2017 09:53:54 GMThttps://devzone.nordicsemi.com/thread/79017?ContentTypeID=1Mon, 20 Mar 2017 09:53:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f091dd8b-571d-4861-beab-4559c9c8db11Petter Myhre<p>If I answered your quesiton please accept my answer by clicking the grey circle next to it.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/79016?ContentTypeID=1Fri, 10 Mar 2017 16:35:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:1b3fc4ca-e38d-4e3a-8ca2-461deb29309fJoonDong<p>Thank you for always helping a lot.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/79015?ContentTypeID=1Thu, 09 Mar 2017 14:45:45 GMT137ad170-7792-4731-bb38-c0d22fbe4515:11141878-ebb6-40e8-8ca6-29a77dd335c8Petter Myhre<p>CSRK is related to LE security mode 2, data signing, see Vol 3, Part C, Section 10.2.2 in the Bluetooth Core 5 specification.</p> <p>Some more information in Vol 3, Part H, Part 2.4.5:</p> <blockquote> <p>An LE device can send signed data without having to establish an encrypted session with a peer device. Data shall be signed using CSRK. A device performing signature verification must have received CSRK from the signing device. The sending device will use its CSRK to sign the transmitted data.</p> </blockquote> <p>LE security mode 2 is not support by any of our SoftDevices.</p><div style="clear:both;"></div>