The value to be used as the Authentication Key in Level 1 and Point-to-Point hello packets while transmitting, whenever the corresponding instance of isisCircL1AuthType has a value of plaintext or md5. A modification of the corresponding instance of isisCircL1AuthType does not modify the hwIsisCircL1TransPassword value. Reading this object always results in an OCTET STRING of length zero; authentication may not be bypassed by reading the MIB object.