Security Architecture of Windows There are three components of Windows Security: LSA (Local Security Authority) SAM (Security Account Manager) SRM (Security Reference Monitor) LSA (Local Security Authority) LSA is the Central Part of NT Security. It is also known as Security Subsystem. The Local Security Authority or LSA is a key component of the logon process in both Windows NT and Windows 2000. In Windows 2000, the LSA is responsible for validating users for both local and remote logons. The LSA also maintains the local security policy. During the local logon to a machine, a person enters his name and password to the logon dialog. This information is passed to the LSA, which then calls the appropriate authentication package. The password is sent in a nonreversible secret key format using a one-way hash function. The LSA then queries the SAM database for the User’s account information. If the key provided matches the one in the SAM, the