Retrospective censorship

[Dave Bird]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

In article <7P5NlZEyBI+6EA2A@turnpike.com>, Richard Clayton
<richard@highwayman.com> writes
>In article <il1K8sDN4C+6EwHD@xemu.demon.co.uk>, Dave Bird
><dave@xemu.demon.co.uk> writes
>
>> The only thing I can suggest it that any article is published
>> with a digital signature, perhaps one whose signing (but not
>> verifying) side is broken after a year, and a notice:
>
>[snip]
>
>crypto can do many interesting (and sometimes implausible) things, but
>interacting in this way with time is not currently known to be possible

 Oh: what happens if, after a year, I erase that private key leaving
 the public in circulation?  Thus people can always check that signature
 but I can make no new signings. Of course you are reliant on my
 (signed and published) statement that I am no longer able to sign
 with that key.  But, if I have told the truth, it follows  I cannot
 deceitfully or under coercion make "retrospective signings" with it.  
 
 Singing should include, within the text signed, the date of signing,
 Multiple persons should have visible, or private, indeces (which they
 would sign and date) of documents which record their signature and date 
 of signing.  By such mechanisms determined schemes to resist scum 
 rewriting history can be made to be effective.

- -- 
   ^-^-^-@@-^-;-^   http://www.xemu.demon.co.uk/
        (..)__u     news:alt.smoking.mooses


-----BEGIN PGP SIGNATURE-----
Version: PGPsdk version 1.7.1

iQA/AwUBOviNKH8v/Y5zkfRPEQKdAwCfTP4RTMQUnuh7ZwDhsHOrGNrDl88AniGN
KU1DWehY8n3Xt1R2g4pfSWWu
=cF5W
-----END PGP SIGNATURE-----