To　provide　mutual　authentication　among　users,　wireless　networks,　and　service　providers　in　roaming　wireless　environments,　this　article　presents　an　anonymous　authentication　and　access　control　protocol.　Bases　on　this　protocol,　entities　of　different　trusted　domains　can　mutually　authenticate　each　other　and　preserve　the　anonymity　of　users.　Hybrid　cryptosystem,　secret　splitting,　and　hash　chains　are　used　in　the　protocol,　which　decrease　computational　loads　and　establish　trusted　relations　for　both　entities.　The　proposed　protocol　has　the　least　computation　complexity　compared　with　other　protocols,　whereas,　the　security　has　been　significantly　improved.　©　2008　The　Journal　of　China　Universities　of　Posts　and　Telecommunications.