This document specifies integrity and replay protection for the Mobile Ad Hoc Network (MANET) Neighborhood Discovery Protocol (NHDP) and the Optimized Link State Routing Protocol version 2 (OLSRv2). This protection is achieved by using an HMAC-SHA-256 Integrity Check Value (ICV) TLV and a Timestamp TLV based on Portable Operating System Interface (POSIX) time. The mechanism in this specification can also be used for other protocols that use the generalized packet/message format described in RFC 5444. This document updates RFC 6130 and RFC 7181 by mandating the implementation of this integrity and replay protection in NHDP and OLSRv2.