trivia

[Richard Clayton]

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In article <156101c10a36$472ce1c0$d400000a@jupiter.92tr.freeserve.co.uk>
, Adrian Midgley <akm@92tr.freeserve.co.uk> writes

>Apropos of which, if you send an encrypted message to a public list,
>does RIPA suggest that all members of that list are assumed to have
>the ability to decrypt the message, unless they can prove that they
>have never had such ability?

RIP S49(2)

    If any person with the appropriate permission under Schedule 2
    believes, on reasonable grounds- 
  
        (a) that a key to the protected information is in the possession
            of any person, 
        (b) that the imposition of a disclosure requirement in respect
            of the protected information is-  
            (i)  necessary on grounds falling within subsection (3), or 
            (ii) necessary for the purpose of securing the effective
                 exercise or proper performance by any public authority
                 of any statutory power or statutory duty, 
        (c) that the imposition of such a requirement is proportionate
            to what is sought to be achieved by its imposition, and 
        (d) that it is not reasonably practicable for the person with
            the appropriate permission to obtain possession of the
            protected information in an intelligible form without the
            giving of a notice under this section, 
    the person with that permission may, by notice to the person whom he
    believes to have possession of the key, impose a disclosure
    requirement in respect of the protected information.

so, the S49 notice server would have to reasonably believe that someone
on the list had the key...  however, having served one notice I don't
think they could continue serving notices on anyone else until the first
notice had timed out and had failed to provide the information [since
the test in (d) wouldn't be met on the second and subsequent notices
until the first one had failed].

>How many people would one have to send the chaff to in order to render
>it embarrassing for an LEA to demand that all for them prove they were
>not the assumed single real destination of the message?

I don't think an LEA that had reasonable grounds would ever be
embarrassed; and one that did not have reasonable grounds would be
acting unlawfully...  so I doubt that the count would be relevant

- -- 
richard                     richard.clayton  @  h i g h w a y m a n . com

"Assembly of Japanese bicycle require great peace of mind" quoted in ZAMM

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