| UUID Generation & Registration |
This feature automatically generates a time-based
UUID for your own use. The 48-bit media Access Control
address (see ISO/IEC
8802-3) that is used is the MAC Address of the
system on which this web server is running.
Acknowledgement: The UUID generator was developed by France Telecom and donated to ITU.
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| What is a UUID? |
A UUID (Universally Unique Identifier) can be used for multiple purposes, from tagging objects with an extremely short lifetime, to reliably identifying very persistent objects across a network, particularly (but not necessarily) as part of an ASN.1 object identifier (OID) value, or in a Uniform Resource Name
(URN).
UUIDs are an octet string of 16 octets (128 bits). The 16 octets can be interpreted as an unsigned integer encoding, and the resulting integer value can be used as a subsequent arc of
{joint-iso-itu-t uuid(25)} in the
OID tree. This enables users to generate OIDs without any registration procedure.
UUIDs forming a component of an OID are represented in ASN.1 value notation as the decimal representation of their integer value, but for all other display purposes it is more usual to represent them with hexadecimal digits with a hyphen separating the different fields within the 16-octet UUID. This representation is defined in
ITU-T Rec. X.667
| ISO/IEC 9834-8.
Example: f81d4fae-7dec-11d0-a765-00a0c91e6bf6 is the hexadecimal notation that denotes the same UUID as
329800735698586629295641978511506172918 in decimal notation.
UUIDs are also known as Globally Unique Identifiers (GUIDs), but this term is not used in
ITU-T Rec. X.667
| ISO/IEC 9834-8. UUIDs were originally used in the Network Computing System (NCS) and later in the Open Software Foundation's Distributed Computing Environment (DCE).
ISO/IEC 11578
"Remote procedure Call (RPC)" contains a short definition of some (but not all) of the UUID formats specified in
ITU-T Rec. X.667
| ISO/IEC 9834-8 which is consistent with all these earlier specifications.
If generated according to one of the mechanisms defined in ITU-T Rec. X.667
| ISO/IEC 9834-8, a UUID is either guaranteed to be different from all other UUIDs generated before 3603 A.D., or is extremely likely to be different (depending on the mechanism chosen). The UUID generation algorithm specified in this standard supports very high allocation rates: 10 million per second per machine if necessary, so UUIDs can also be used as transaction IDs.
No centralized authority is required to administer UUIDs but central registration of self-generated UUIDs and automatic generation of UUIDS (using the algorithm defined in
ITU-T Rec. X.667
| ISO/IEC 9834-8) are provided at the top of this web page. Centrally generated UUIDs are guaranteed to be different from all other UUIDs centrally generated. Registered UUIDs are guaranteed to be different from all other registered
UUIDs.
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| Why register a UUID? |
The objective of the registration should be seen
mainly as a means of publishing the UUID and its
semantics.
The Registration Authority for UUIDs is a dedicated
web page of the OID repository. It guarantees
the uniqueness of registered UUIDs. An attempt to
separately register the same UUID will fail, with
a link to the current registration details.
Government health warning: It is important
to note that an unregistered UUID can be used under
the same arc (namely, {joint-iso-itu-t(2) uuid(25)})
as that of a registered UUID. Thus identical values
for a registered UUID and an unregistered UUID (or
for two unregistered UUIDs) might be used, although
the probability of this occurring is very small.
The probability is increased if UUIDs are generated
from
MD5 hash values or pseudo-random numbers, rather
than from
SHA-1 hash values and cryptographic-quality
random numbers.
This may cause confusion for the users of the OID,
and could be the trigger of malicious use such as
spoofing. The Registration Authority for UUIDs is
responsible for a collision between registered UUIDs,
but it is not responsible for a collision between
a registered UUID and an unregistered UUID because
it does not manage unregistered UUIDs. If such a
collision occurs, the semantics associated with
the registered UUID should have precedence; the
semantics associated with the unregistered UUID
value should not be used. Thus, the registration
of an OID with a UUID does not ensure that the OID
has more uniqueness than its UUID's uniqueness.
Disclaimer: The Registration Authority for
UUIDs shall not be liable for any failure to operate
under the procedures specified in ITU-T Rec. X.667
| ISO/IEC 9834-8, or for any actions related to
its duties in relation to this standard. The Registration
Authority for UUIDs shall not be held liable for
any use of an unregistered OID value that is the
same as a registered OID value, as it has no control
over the use of such values
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| Use of a UUID as a URN |
A URN (see IETF RFC
2141) formed using a UUID shall be the string "urn:uuid:" followed by the hexadecimal representation of a UUID.
Example: The following is an example of the string representation of a UUID as a URN:
urn:uuid:f81d4fae-7dec-11d0-a765-00a0c91e6bf6
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