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 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.
hashes and checksums: The collision-resistant substrate of a sequence of bytes. Well-known hash algorithms for computing hashes include MD4, MD5, and SHA1.
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 Health Certificate Enrollment Protocol.
health policy server: An entity in a network that has network polices administered on it and that is capable of validating a statement of health (SoH) against the specified polices.
health state: An abstract notion of the state of a machine used to indicate its compliance with network polices. 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 containing 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: 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.
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 process that occurs when the DirectPlay peer that is designated as the host leaves the DirectPlay game session, and the next oldest peer becomes the host. The algorithm employed during the host migration process is specified by the Host Migration Extension.
HRESULT: An opaque integer result value where the high bit indicates an error. Some protocols use a constrained set of the HRESULT values where the only legal success value is 0x00000000. Any such protocols are responsible for documenting the fact that other success codes cannot be used.
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 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.