What is the authentication protocol used in 2008?

Answer 1

The Windows operating systems implements a default set of authentication protocols-Kerberos, NTLM, TLS/SSL, Digest, and PKU2U-as part of an extensible architecture. In addition, some protocols are combined into authentication packages such as the Credential Security Support Provider (CredSSP), Negotiate, and Negotiate Extensions. These protocols and packages enable authentication of users, computers, and services; the authentication process, in turn, enables authorized users and services to access resources in a secure manner.

Windows authentication protocols are conventions that control or enable the connection, communication, and data transfer between computers in a Windows environment by verifying the identity of the credentials of a user, computer, or process. The authentication protocols are security support providers (SSPs) that are installed in the form of dynamic-link libraries (DLLs).

Negotiate

Microsoft Negotiate is an SSP that acts as an application layer between the Security Support Provider Interface (SSPI) and the other SSPs. When an application calls into SSPI to log on to a network, it can specify an SSP to process the request. If the application specifies Negotiate, Negotiate analyzes the request and selects the best SSP to handle the request based on the configured security policy.

Currently, the Negotiate SSP selects either the Kerberos or NTLM protocol. Negotiate selects the Kerberos protocol unless it cannot be used by one of the systems involved in the authentication or if the client application did not provide a target name as a service principal name (SPN), a user principal name (UPN), or a NetBIOS account name. Otherwise, Negotiate will select the NTLM protocol.

A server that uses the Negotiate SSP can respond to client applications that specifically select either the Kerberos or NTLM protocol. However, a client application must first query the server to determine if it supports the Negotiate package before using Negotiate. (Negotiate is supported on Windows operating systems beginning with Windows Server 2003 and Windows XP.) A server that does not support Negotiate cannot always respond to requests from clients that specify Negotiate as the SSP

Kerberos

:The Kerberos version 5 (v5) authentication protocol provides a mechanism for authentication-and mutual authentication-between a client and a server, or between one server and another server

NTLM

The NTLM version 2 (NTLMv2) authentication protocol is a challenge/response authentication protocol. NTLM is used when exchanging communications with a computer running Windows NT Server 4.0 or earlier. Networks with this configuration are referred to as mixed-mode. NTLM is also the authentication protocol for computers that are not participating in a domain, such as stand-alone servers and workgroups.

Negotiate Extensions

NegoExts (NegoExts.dll) is an authentication package that negotiates the use of SSPs for applications and scenarios implemented by Microsoft and other software companies. Pku2u.dll is one of the supported SSPs that is installed by default, and developers can create custom providers.

PKU2U

The PKU2U protocol in Windows 7 and Windows Server 2008 R2 is implemented as an SSP. The SSP enables peer-to-peer authentication, particularly through the Windows 7 media and file sharing feature called Homegroup, which permits sharing between computers that are not members of a domain.

Credential Security Support Provider

Windows Vista introduced a new authentication package called the Credential Security Support Provider (CredSSP) that provides a single sign-on (SSO) user experience when starting new Terminal Services sessions. CredSSP enables applications to delegate users' credentials from the client computer (by using the client-side SSP) to the target server (through the server-side SSP) based on client policies

TLS/SSL

The TLS/SSL protocols are used to authenticate servers and clients, and to encrypt messages between the authenticated parties. The TLS/SSL protocols, versions 2.0 and 3.0, and the Private Communications Transport (PCT) protocol are based on public key cryptography. The secure channel (Schannel) authentication protocol suite provides these protocols. All Schannel protocols use a client/server model and are primarily used for internet applications that require secure Hypertext Transfer Protocol (HTTP) communications

Digest

The Digest authentication protocol is a challenge/response protocol that is designed for use with HTTP and Simple Authentication Security Layer (SASL) exchanges. These exchanges require that parties requesting authentication must provide secret keys.