'Creates a communicator.
Args:
certificate: Our own certificate.
private_key: Our own private key.'

def __init__(self, certificate=None, private_key=None):

    self.private_key = private_key
    self.certificate = certificate
    self.server_cipher = None
    self.server_cipher_age = rdfvalue.RDFDatetime().FromSecondsFromEpoch(0)
    self.encrypted_cipher_cache = utils.FastStore(max_size=50000)
