（在RFC 2759中定义）。MS-CHAPv2在Windows NT 4.0 SP4中引入，后来被加到Windows 98（通过"Windows 98 Dial-Up Networking Security Upgrade Release"）和Windows 95（通过"Dial Up Networking 1.3 Performance & Security Update for MS Windows 95"升级）中去。Windows Vista不再支持MS-CHAPv1。MS-CHAP被当做一个认