An intermediary step which allows the testing of communication infrastructure are trusted repeaters. Importantly, a trusted repeater cannot be used to transmit qubits over long distances. Instead, a trusted repeater can only be used to perform quantum key distribution with the additional assumption that the repeater is trusted. Consider two end nodes A and B, and a trusted repeater R in the middle. A and R now perform quantum key distribution to generate a key k A R . Similarly, R and B run quantum key distribution to generate a key k R B . A and B can now obtain a key k A B between themselves as follows: A sends k A B to R encrypted with the key k A R . R decrypts to obtain k A B . R then re-encrypts k A B using the key k R B and sends it to B. B decrypts to obtain k A B . A and B now share the key k A B . The key is secure from an outside eavesdropper, but clearly the repeater R also knows k A B . This means that any subsequent communication between A and B does not provide end to end security, but is only secure as long as A and B trust the repeater R.