Transport Layer SecurityDefined in RFC5246
The primary goal of the TLS protocol is to provide privacy and data integrity between two communicating applications.
Transport Layer Security is a cryptographic protocol designed to provide communications security over a computer network. There are several versions of the protocol, and it finds widespread use in applications such as browsing, email, instant messaging, and VoIP. Websites can use tables to secure all communications between their servers and web browsers. Note: SSL is deprecated for TLS -- but, for the most put, TLS is just the new name of SSL -- It get's called by either name but officially it's TLS now.
TLS uses "Certificate Authorities" (CA files) that check and sign for authenticity of a public key certificate from a server. A client connecting to the server via TLS may verify it's certificate authenticity by relying on the digital signature of the CA.
Default mecanisms for loading a default CA certificates include OpenSSL, GnuTLS, Network Security Services, mbedTLS, and LibreSSL. The majority of these mechanisms provide API functions that load certificates from a hardcoded directory or file. Some, such as Network Security Services load the certficiates from a dynamically configured list of PKCS #11 modules, managed with a dedicated API, and configuration can be stored in any directory pointed to by a user.
Elliptic Curves are a newer encrpytion algorithm and are becoming increasingly adopted for modern systems. A 256-bit elliptic curve key is expected to provide sufficient security through the year 2030. where an older RSA cryptosystem has higher compatibility, (especially with clients that do not support recent versions of TLS ) but relies on factorization, which is an area of cryptograhpy that's becomign weaker due to the development of faster factorization algorithms. A 2048-bit RSA private key is expected to provide security through most of the 2020s. A 4096 bit RSA private key is expected to provide security for a bit longer (barring major advancements in factorization), but has a very large performance impact.