What following parameters for the EIGRP authentication need to match in order for EIGRP neighbors to establish a neighbor relationship?

While EIGRP neighbors must generally share the same Autonomous System number to exchange routes, this is a general requirement for neighbor establishment, not specifically an authentication parameter.

K-values must match for EIGRP neighbors to form an adjacency and correctly calculate routes, but they are not parameters of the authentication mechanism itself.

When EIGRP authentication is configured using key chains, all parameters for the active key must precisely match between neighbors: the key number (key-id), the password (key-string), and the key's validity period (defined by accept-lifetime and send-lifetime date/time values). These matching parameters ensure mutual authentication and message integrity for establishing the neighbor relationship.

Neighbors must be on a common subnet to establish a direct adjacency, which is a general rule for many IGPs, but this is a network layer requirement, not an authentication parameter.