LSAs

LSAs are acronyms that can refer to several concepts in computer science and networking. The most common usages are in Windows security, in routing protocols that exchange topology information, and in natural language processing as a dimensionality-reduction technique.

Local Security Authority refers to the Windows component responsible for enforcing security policies and authentication. The Local Security Authority, including the LSASS process, handles logon requests, credential storage, and ticket issuance for features such as Kerberos and NTLM. It communicates with the Security Accounts Manager and protects sensitive secrets in memory.

Link-State Advertisements are a class of messages used by some routing protocols, notably OSPF, to advertise the network topology. Routers share LSAs to build a consistent link-state database, which is then analyzed by the SPF algorithm to compute shortest paths. OSPF defines several LSA types, such as Router, Network, Summary, and AS-external LSAs, each serving a different purpose, with an emphasis on reliable flooding to all area routers.

Latent Semantic Analysis is a statistical technique in natural language processing that uses a term-document matrix, singular value decomposition, and dimensionality reduction to uncover conceptual relationships between words and documents. LSA improves information retrieval by capturing synonyms and contextual shifts, and it has been applied to indexing, search, topic modeling, and recommendation tasks.