Re: dna ink

At 6:39 PM 02/06/95, root wrote:
>The blood is water soluble and many of the componants breakdown over time. By
>injecting DNA (which has lifetimes measured in millions of years) in some kind
>of matrix (ie epoxy or cyanoacetates) it becomes possible to create a modern
>'seal' similar to the wax seals of yesteryear. In the case of the old seals it
>was not the wax which provided the protection but rather the symobigy that was
>embedded in it (ie DNA).
>
>And you thought that T Rex forward from the dinosaur mailing list about DNA
>from dinosaur bones was unrelated to crypto......bwahahahahaha

Something I've been is: Why can't one of your enemies just get a piece of
your hair or fingernails or something, and make their own DNA ink our of
your DNA?  They could probably even send it to this DNA ink company, and
they'd make your enemy ink out of your own DNA without even noticing.
Doesn't seem very secure to me.

[Yeah, it's not crypto related, but I've been wondering about this since
the topic was first brought up, and am somewhat surprised that of the few
messages there were making fun of the DNA ink,  none mentioned this fact.
Is that because it's too obvious to mention, or is there something I'm not
thinking about which makes DNA ink useful after all?]

> 
> Something I've been is: Why can't one of your enemies just get a piece of
> your hair or fingernails or something, and make their own DNA ink our of
> your DNA?  They could probably even send it to this DNA ink company, and
> they'd make your enemy ink out of your own DNA without even noticing.
> Doesn't seem very secure to me.
> 
> [Yeah, it's not crypto related, but I've been wondering about this since
> the topic was first brought up, and am somewhat surprised that of the few
> messages there were making fun of the DNA ink,  none mentioned this fact.
> Is that because it's too obvious to mention, or is there something I'm not
> thinking about which makes DNA ink useful after all?]
> 
> 
This is the same problem that arose with the original idea of seals once
the skills of metalworking became commen enough. By the 1500's it was
nearly impossible to keep a seal confidential more than a few weeks until
somebody got a impression and built a copy.

root says:
> This is the same problem that arose with the original idea of seals once
> the skills of metalworking became commen enough. By the 1500's it was
> nearly impossible to keep a seal confidential more than a few weeks until
> somebody got a impression and built a copy.

Seals were duplicatable from the start. You just needed clay and a
seal made with the oritinal if you wanted to forge them -- fairly
common stuff. Signatures have been duplicatable from the start, too.

Signatures and seals are NOT truly authenticating technologies. They
are just a legal mechanism for an entity to demonstrate that it has
read and agreed to the terms on a document. It was always assumed that
someone might forge a signature, which is why if you had a document
where you cared that people might disclaim their signature, you got
people who could testify to the signature to witness the signing.

Digital "signatures" are the first real unforgeable authentication
technology mankind has developed.

Perry

From: "Perry E. Metzger" <perry@imsi.com>

   Digital "signatures" are the first real unforgeable authentication
   technology mankind has developed.

Impossibility is a pretty strong concept, and here, as elsewhere, it's
an exaggeration.  Digital signatures are not unforgeable.  If you
steal the private key, you can forge signatures.  The unforgeability
is exactly as great as the strength of the container where the private
key lies.  The issue of incarnation, if you will, is perhaps the
single most important issue for actual deployment.

It's a matter of economics.  The cryptographic barrier is
insurmountable, but it's not the only barrier.  So don't try to breach
the cryptography; try to breach one of the other elements of the
system.

[Perry, I promise it's not personal; it just _seems_ like I'm
nit-picking on everything you write this week.]

A remark on the meaning of forgery.  Let me rewrite what Perry said:

   Digital "signatures" are the first authentication technology
   mankind has developed where forgery is impossible to detect.
   
An indistinguishable signature can still be a forged signature.  A
forged signature is one that is made by the wrong person.  If the
wrong person gets the private key, signatures made by that person are
forgeries, even though nobody can tell them apart.

This point is not merely pedantic.  The concept of forgery adheres to
the person committing the act, not the act itself.  A piece of data
which presents itself as a signature, but which does not pass the
verification process, is not a forged signature but an invalid one.

The external inability to distinguish proper digital signatures from
forged ones has profound effect on the legal interpretations of the
physical signing device (hardware+software).  I wish only to point
this out and leave discussion to another thread.

Eric

Eric Hughes says:
>    From: "Perry E. Metzger" <perry@imsi.com>
> 
>    Digital "signatures" are the first real unforgeable authentication
>    technology mankind has developed.
> 
> Impossibility is a pretty strong concept, and here, as elsewhere, it's
> an exaggeration.

Naturally -- but the other methods were complete jokes -- forging a
signature requires nothing more than a pen and slight practice.

> The concept of forgery adheres to
> the person committing the act, not the act itself.

Indeed -- which is why witnesses used to be the primary verification
technology, and not graphologists...

Perry

...
> your DNA?  They could probably even send it to this DNA ink company, and
> they'd make your enemy ink out of your own DNA without even noticing.
> Doesn't seem very secure to me.
> 
> [Yeah, it's not crypto related, but I've been wondering about this since
> the topic was first brought up, and am somewhat surprised that of the few
> messages there were making fun of the DNA ink,  none mentioned this fact.
> Is that because it's too obvious to mention, or is there something I'm not
> thinking about which makes DNA ink useful after all?]
> 

A much more interesting spin on this would be a variety of ways to encode
throughout a substance in an inert but permanent way a public key.

Whether it's an easily identifiable molecule or some type of deep etching,
you could do things like mark all the parts of a car or all the paint,
fabric, plastic, etc. of a work of art.

DNA isn't very good really since it's mostly the same and based a lot
on probabilities.

sdw
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