In this video I show how to capture GSM traffic over the air, and decrypt our own SMS!

It’s highly recommended to check out the previous videos, in case this is the first time you’re doing GSM sniffing and decryption.

Topics covered:
– Switching USB mode on a Samsung Galaxy phone
– ARFCN conversion to downlink and uplink frequencies
– Testing the GSM downlink frequency
– Capturing RTL-SDR GSM traffic for later use
– Decoding RTL-SDR GSM traffic
– GSM packets (Immediate Assignment, Cipher Mode Command, etc.)
– Decrypting GSM traffic with a known Kc (symmetric encryption key)

– usbswitcher (
– minicom
– kalibrate-rtl (kal)
– grgsm_livemon
– grgsm_capture
– grgsm_decode
– wireshark

Hardware requirements:
– RTL-SDR (Default antenna)
– Cellphone that has an AT interface you can access.

Stay tuned and subscribe for more upcoming videos showing actual hacks!

Many thanks to for sharing the GSM Sniffing & Hacking video playlist!