mikeryan/crackle

Crackle is an open-source security tool that cracks Bluetooth Low Energy (BLE) encryption, also known as Bluetooth Smart. It exploits a flaw in the BLE pairing process to brute force the Temporary Key (TK), which is often a weak value (0–999999) for Just Works or 6-digit PIN pairing. Using the TK and captured pairing data, crackle derives the Short Term Key (STK) and Long Term Key (LTK), enabling full decryption of encrypted communications between master and slave. The tool supports two modes: Crack TK (default) – automatically brute forces the TK from a PCAP/PcapNG file containing a BLE pairing event and outputs a decrypted PCAP; and Decrypt with LTK – uses a user-supplied LTK to decrypt captured traffic. It is written in C and available on GitHub under a permissive license.