GPU/CPU cracker that recovers an A5/1 session key from a captured keystream segment using the ~1.6–2 TB A5/1 rainbow tables (the Berlin A5/1 Security Project). Recovers Kc, which decrypts the rest of a captured call/SMS session. Old but the reference open A5/1 attack; requires the bulky precomputed tables and a known-keystream slice from the capture.