GSM Sniffing: Voice Decryption 101 - Software Defined Radio Series #11

In this video I show how to capture GSM traffic over the air, and decrypt parts of our own voice call. As frequency hopping is enabled in our case, a “test call“ is decrypted subsequently, to show the full process until I get my new SDR, and record a new video. Please note that the pace in this video is quite fast at times, to keep the time on the video down a bit. It’s also highly recommended to check out the previous videos, in case this is the first time you’re doing GSM sniffing and decryption. Generally speaking, decoding voice where frequency/channel hopping is disabled/off, is almost the same as decrypting SMS’s. The only difference is an extra step at the end, where the TCH/F channel is used for speech data. New topics covered in this video: - Voice calls decryption (Traffic channels (TCH/F), channel hopping, etc.) - RTL-SDR limitations in relation to frequency hopping - Decrypting the test call file by “Security Research Labs“