Break-Open One-Shot Password Stores

David Biggins David_Biggins at
Mon Feb 27 09:59:03 GMT 2012

Hi Ian

Don't know whether they would fit the bill or not,   but   Postsafe
claim to do tamper-evident uniquely numbered security envelopes.

I wouldn't however try going to a postsafe com website to try for more
details - my AV got very unhappy just now.   Which assuming it is the
same company,  does not totally inspire warm feelings.


> -----Original Message-----
> From: ukcrypto-bounces at [mailto:ukcrypto-
> bounces at] On Behalf Of Ian Batten
> Sent: 27 February 2012 7:43 AM
> To: UK Cryptography Policy Discussion Group
> Subject: Break-Open One-Shot Password Stores
> Fictional films of nuclear missile launch processes show passwords and
> key material stored in plastic enclosures which are broken in order to
> the secret.  The idea presumably is that you can check that the key
> has not been accessed without exposing it.  Whether it's true or not,
it's a
> neat way to deal with "break glass" processes for storing the root
> to servers, the back-stop copy of your lastpass password for your
executor or
> enduring power of attorney, etc.
> Has anyone seen such devices for sale?  It wouldn't be hard to do it
> with a lucite box and some araldite, but it would probably require a
tool to
> break open and it's hard to be sure that the system doesn't have a
back door:
> presumably the "real" items would be very weak in one plane, so they
> easy to break and any force applied to attempt to open them otherwise
> break that weak point.
> ian

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