The value to be used as the Authentication Key in Level 2 and Point-to-Point hello packets while transmitting, whenever the corresponding instance of isisCircL2AuthType has a value of plaintext or md5. A modification of the corresponding instance of isisCircL2AuthType does not modify the hwIsisCircL2TransPassword value. Reading this object always results in an OCTET STRING of length zero; authentication may not be bypassed by reading the MIB object.