Two peers already exchanged their ECDSA (curve secp256k1) public keys using a secure channel.
They want to establish an authenticated encrypted channel between them. They will use CCM mode and with the AES block cypher (as implemented in the SJCL crypto library).
Is it safe for them to use as a key for CCM the output of PBKDF2(iter=1000) of the other peer's pubkey? Is there a better solution without exchanging more data off channel?
(public keys are 33 bytes long).
EDITED: These pubkeys are not public, only shared between the two peers.