  We analyze the performance of continuous-variable quantum key distribution
protocols where the entangled source originates not from one of the trusted
parties, Alice or Bob, but from the malicious eavesdropper in the middle. This
is in contrast to the typical simulations where Alice creates the entangled
source and sends it over an insecure quantum channel to Bob. By using previous
techniques and identifying certain error correction protocol equivalences, we
show that Alice and Bob do not need to trust their source, and can still
generate a positive key rate. Such a situation can occur in a quantum network
where the untrusted source originated in between the two users.
