MQV (Menezes-Qu-Vanstone) is an authenticated protocol for key agreement based on the Diffie-Hellman scheme. Like other authenticated Diffie-Hellman schemes, MQV provides protection against an active attacker. The protocol can be modified to work in an arbitrary finite group, and, in particular, elliptic curve groups, where it is known as elliptic curve MQV (ECMQV).
MQV is incorporated in the public-key standard IEEE P1363.
Some variants of MQV are claimed in patents assigned to Certicom http://www.certicom.com/index.php?action=ip,protocol.
MQV has some weaknesses that were fixed by HMQV in 2005 http://eprint.iacr.org/2005/176; see http://eprint.iacr.org/2005/205, http://www.ams.org/notices/200708/tx070800972p.pdf, http://www.ams.org/notices/200711/tx071101454p.pdf for an alternative viewpoint.
ECMQV has been dropped from the National Security Agency's Suite B set of cryptographic standards.