serial number

Each BCM2837 SoC has an unique serial number which is, among others, used for licensing additional video codecs.

Retrieve serial number:

root@raspberrypi2:~# cat /proc/cpuinfo
...
Hardware : BCM2709
Revision : a02082
Serial   : 00000000b83c3c1b

From the serial number, also the MAC addresses of the various network interfaces are calculated:

root@raspberrypi2:~# cat /sys/class/net/eth0/address
b8:27:eb:3c:3c:1b
root@raspberrypi2:~# cat /sys/class/net/wlan0/address
b8:27:eb:69:69:4e
cat /sys/class/bluetooth/hci0/address
b8:27:eb:96:96:b1

(hci0 works only when bluetooth is activated.)

The serial number is programmed in the on-chip OTP fuses which can be read using vcgencmd

vcgencmd otp_dump