10 H

handle: Any token that can be used to identify and access an object such as a device, file, or a window.

handshake: An initial negotiation between a peer and an authenticator that establishes the parameters of their transactions.

hard disk: A peripheral device that provides persistent data storage and does not have removable media.

hard disk drive: A diskdrive that controls the positioning, reading, and writing of the hard disk.

hard disk physical name: An implementation-specific path that can be used to refer to a specific hard disk on a machine.

Hash-based Message Authentication Code (HMAC): A mechanism for message authentication using cryptographic hash functions. HMAC can be used with any iterative cryptographic hash function (for example, MD5 and SHA-1) in combination with a secret shared key. The cryptographic strength of HMAC depends on the properties of the underlying hash function.

hash function: A function that takes an arbitrary amount of data and produces a fixed-length result (a "hash") that depends only on the input data. A hash function is sometimes called a message digest or a digital fingerprint.

hash window: The length, in bytes, of the domain of the rolling hash function. That is, the parameter n in the definition of rolling hash function.

hashes and checksums: The collision-resistant substrate of a sequence of bytes. Well-known hash algorithms for computing hashes include MD4, MD5, and SHA-1.

health certificate: (1) A digital certificate that is used to authenticate the health status of a Network Access Protection (NAP) client.

(2) An X.509 certificate that is used to certify the health state of a machine as determined by the policies administered for a network.

health certificate enrollment agent (HCEA): The client-side component in the Health Certificate Enrollment Protocol. The HCEA is responsible for receiving health certificates from a health registration authority (HRA). This term can also be used to refer to the client machine in the Health Certificate Enrollment Protocol.

health ID: An identifier of a component or service that supplies host status information in a statement of health (SoH) message or that performs evaluation of host status information in a Statement of Health Response (SoHR) message.

health messages: The set of messages exchanged between peers or clients and servers. These messages are of the types statement of health (SoH) and statement of health response (SoHR).

health policy server: An entity in a network that has network policies administered on it and that is capable of validating a statement of health (SoH) against the specified policies.

health registration authority (HRA): The server-side component in the Health Certificate Enrollment Protocol. The HRA is a registration authority (RA) that requests a health certificate from a certification authority (CA) upon validation of health.

health state: An abstract notion of the state of a machine that is used to indicate its compliance with network policies. Some examples of such state would include the state of the firewall on the machine, the version of the virus signature files for an antivirus application, and so on.

HexConvertedUnicodeString: A Unicode string created from a binary, byte-granular value. The string is created by converting each byte, starting with the most significant byte and ending with the least significant byte, into two Unicode characters. The characters are the hexadecimal representation of each nibble of the byte, starting with the high-order nibble.

hibernation image: An image that contains metadata required to support a Windows operating system feature known as hibernation. Hibernation allows a system's state to be preserved in persistent storage while the system is shut down.

HMAC: See Hash-based Message Authentication Code (HMAC).

host: (1) A general-purpose computer that is networking capable.

(2) In DirectPlay, the computer responsible for responding to DirectPlay game session enumeration requests and maintaining the master copy of all the player and group lists for the game. One computer is designated as the host of the DirectPlay game session. All other participants in the DirectPlay game session are called peers. However, in peer-to-peer mode the name table entry representing the host of the session is also marked as a peer.

host bus adapter (HBA): (1) A hardware device that adapts the signals of one electronic interface to another.

(2) An HBA that can be discovered by way of the SNIA Common HBA API on the system. For more information, see [HBAAPI].

host migration: The protocol-specific procedure that occurs when the DirectPlay peer that is designated as the host or voice server leaves the DirectPlay game or voice session and another peer assumes that role.

HRESULT: An integer value that indicates the result or status of an operation. A particular HRESULT can have different meanings depending on the protocol using it. See [MS-ERREF] section 2.1 and specific protocol documents for further details.

HTTP client: A program that establishes connections for the purpose of sending requests, as specified in [RFC2616].

HTTP Internal Server Error: An HTTP response with status code 500, as specified in [RFC2616] section 6.1.1.

HTTP OK: An HTTP response with status code 200, as specified in [RFC2616] section 6.1.1.

HTTP proxy: An intermediary program that acts as both a server and a client for the purpose of making requests on behalf of other clients. For more information, see [RFC2616].

HTTP server: An application that accepts connections in order to service requests by sending back responses. For more information, see [RFC2616].

Hypertext Transfer Protocol (HTTP): An application-level protocol for distributed, collaborative, hypermedia information systems (text, graphic images, sound, video, and other multimedia files) on the World Wide Web.

Hypertext Transfer Protocol over Secure Sockets Layer (HTTPS): An extension of HTTP that securely encrypts and decrypts web page requests.