The TETRA TEA1 keystream generator implements a key register initialization function that compresses the 80-bit key to only 32 bits for usage during the keystream generation phase, which is insufficient to safeguard against exhaustive search attacks.

The TETRA TEA1 keystream generator implements a key register initialization function that compresses the 80-bit key to only 32 bits for usage during the keystream generation phase, which is insufficient to safeguard against exhaustive search attacks.