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Lions, Bob; Greenleaf, Graham --- "A public key authentication framework for Australia"  PrivLawPRpr 24; (1996) 3(2) Privacy Law & Policy Reporter 28
A public key authentication framework for Australia
law for agreements and contracts is based largely on the placement of a written
signature on a paper document or a verbal
agreement between parties who are
satisfied that they can sufficiently identify one another. This is not
satisfactory for deals in
cyberspace, either in terms of validity of
identification or repudiation of valid transactions. What is needed is an
system which is secure, flexible, acceptable and trusted.
A small task group established under the auspices of the Standards Australia
Joint Electrotechnology Policy Board is looking at a solution for Australia and
this article is an attempt to give the story so far.
The Task Group is endeavouring to keep small for speed and is producing an
implementation strategy document for a public key authentication
(PKAF) for Australia. While the subject has been under discussion for a number
of years, the work only came to the Task
Group early in 1995. The group has
been very sensitive to previous activities and accordingly is proposing the
system, designed to provide a framework in which users can
have confidence and which initially avoids the `bells and whistles' which
others may wish to add.
The proposal to date is based on the `KISS' principle -- Keep it simple! So the
following principles are being taken as given:
principles indicated above will hopefully lead to a simple, trusted system
which will provide the necessary electronic signature
system for Australia in
such a form that it will be recognised in other countries. The principles are
further expanded below, exploring
their wider ramifications, and hopefully
convincing the reader that they are appropriate.
The key is for identification of a person or entity only and is not intended
for encryption or any other purpose.
The private key will only be accessible to the key owner.
- There will be no need for key escrow or similar key-lodgement systems.
Proof similar to that necessary to obtain a passport will be necessary for
an individual to obtain a key and the cost of the service
is expected to be
The life of a key is expected to run from the time of issue till the public
key is revoked by an entry in the Certificate Revocation
There will be need for an enhanced legislative definition of `signature'
which is used about 5000 times in existing legislation.
The whole system will depend on trust but that every effort should be made
to reduce the possibilities for fraud, either in supply
of keys or in their
Other features may be combined with the system as commercial imperatives
dictate and as users are prepared to accept.
There will be a single, hierarchical, nationally recognised structure.
this brief article I have attempted to illustrate some of the important
features which make this project so vital to Australia.
A simple, straight
forward approach to electronic signatures is proposed. While the project is not
yet completed, it is anticipated
that the draft strategy document will be
offered for public review soon (see accompanying note: Editor). This is
part of a two stage process which will see all comment taken into account
before the final report is issued.
Bob Lions, Group Manager, Information & Communications, Standards Australia.
The first principle is fundamental in that we are intending merely that
there will be an electronic certificate which links a specific
name and a
public key. This may be the name of an individual or an organisation. The
individual will need to prove his or her identity
to a level sufficient to
obtain a passport (see principle 4) in order to given an electronic identity.
Companies will need to use
appropriate company documentation to obtain a
certificate. The use of aliases is not precluded nor will the issue of
conferring for example, a financial delegation. These
will be issued by other authorities.
Within the second principle is the proposal that the private key will be
delivered in such a way that no-one other than the owner
should be able to have
access to it. It is envisaged that even the owner may never actually `see' the
key. However, he or she will
have the only means of generating it. If lost or
compromised, it will have to be replaced with a new, different, key. The
public key will remain available to ensure that all valid transactions
(up till the key was revoked) can be certified. Thereafter
it will be
- As this is an identity, there is no need for it to be other than with its
owner. While the government may possess all details necessary
to recreate a
facsimile of a passport, there is an original signature which makes the
- This principle is closely associated with (1) but also indicates that an
electronic signature is not mandatory, and like a passport,
need only be
obtained by those who need one. The issuing fee would be similar which it is
anticipated would mean that people will
look after their signatures equally
- Key life is expected to be about three to five years, depending on the trust
which the algorithms and key lengths give. Where a single
key is compromised,
it will need to be replaced, but should an algorithm be discredited, then all
keys will need replacement. As
part of the process of keeping things simple,
date stamping and notary services are not covered. However, there is nothing
others from providing such services as extensions beyond the
- The strategy document will cover aspects well beyond the bounds of a normal
standards document by providing guidance for the legislation
needed as well as
a clear picture of what features the standard will need to cover.
- The framework will include policy directives requiring key issuers to take
auditable steps which should provide confidence that security
will not be
breached. What the owner of an identity does with that identity is difficult to
control. It is intended that use of an
unrevoked electronic signature will
constitute prima facie evidence that the action concerned was the
responsibility of the owner
of the signature.
- While other countries and groups seeking to establish similar systems are
talking of associating other functions, it has been felt
that simplicity will
assist the scheme to commence. Extensions would then be paced to suit users and
in line with commercial dictates
of the service providers.
- A single recognised hierarchical national structure appears to offer the
simplest system to provide for the necessary legislative
adjustments as well as
enabling the easiest establishment of the necessary bi-lateral recognition
agreements with other PKAF systems
in other regions of the world.
Standards Australia has released draft standard DR 96078 `Strategies for
implementation of a public key authentication framework
in Australia' ($13 plus
$7 postage from Standards Australia). The public comment phase finished on 29
The draft standard proposes a `single, hierarchical, nationally recognised
structure' (as described by Bob Lions) for digital signature
elements of which can be summarised as follows (paraphrased courtesy of Robin
A PKAF is concerned with supplying the public keys of individuals and
organisations so that signatures created with the corresponding
private key can
be validated. The PKAF does not store private keys and the public keys if
publishes are intended only for use with
digital signatures -- not
The peak national Policy And Root Registration Authority (PARRA) for
Australia will determine standards and certify ICAs. Legislation
digital signatures validated under the PARRA's system the same legal status as
handwritten signatures without the need
for any prior arrangements.
- There will be many Intermediate Certification Authorities (ICAs) which meet
all PARRA's requirements but have their own discretions
and policies. There
might be a banking ICA, a defence ICA and one or more ICAs which specialise in
serving particular sectors of
society. Australia Post, for instance could be a
major ICA -- and has announced its `Key Post' service. An ICA can directly sign
Public Key Certificates or it can delegate to OCA's. ICA's have a central role
in providing Public Key Certificates on request.
- Under an ICA, there can be multiple Organisational Certification Authorities
(OCAs). which can also directly sign Public Key Certificates.
OCAs can have
OCAs underneath them.
- Organisational Registration Authorities (ORAs) are like shop-fronts for OCAs
and ICAs -- for example a local Australia Post Office.
An ORA does not itself
sign the Public Key Certificates, but it acts as a conduit for these
A discussion of DR 96078 and an introduction to the concepts underlying digital
signatures by Robin Whittle of First Principles Consulting
can be found at
http://www.ozemail.com.au/~firstpr/crypto/pkaf-1.htm. An analysis of the
privacy implications of the draft standard will appear in a later issue of
Graham Greenleaf, General Editor.