Unique ARM ID [Appendix]

Describes ARM unique ID's. More...

Classes
interface	OpenGroup::arm40::Provisional::transaction::IArmID
	Implements an immutable wrapper around a 16-byte ID. More...

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Detailed Description

An ID is unique if the probability of the ID being associated with more than one set of metadata is vanishingly small. The selection of 128-bit IDs yields 3.4 x 10^38 unique IDs, so the objective is to select an ID that makes use of all 128 bits and is reasonably likely to not be selected by another person creating an ID of the same form. Two suggested algorithms that generate 128-bit values with these characteristics are:

1. The Universal Unique Identifier (UUID) algorithm that is part of The Open Group specification DCE 1.1: Remote Procedure Call. A developer could use the algorithm at the time the application is developed using a utility on his or her system, and be reasonably certain that nobody else would generate the same 128-bit ID.
2. The MD5 Message-Digest Algorithm, described in IETF RFC 1321. Applying this algorithm to a concatenation of all the metadata properties would almost certainly result in a value that would not collide with any other ID created with a different set of metadata properties.