Personal use of encryption was - Re: CGT and other whinges

[Robin Whittle]

Tony Barry wrote, in part:

> 1. I can get good encryption software off the net now of the kinds
> governments say is naughty as its too hard for them to break.

Yes.

> 2. Forget browsers and all these bells and whistles. I can use the
> software to encrypt a file on my machine with my private key.

You could, but that is not the usual approach.  If you want to secure 
a file against attacks by the goon-squad or some other compromise of 
your computer, encrypt it with your public key - then it can only be 
deciphered with your private key.  You should have created the key-
pair yourself and made sure that only you posess a copy of the 
private key.

Likewise, if you want to send a secret message to Greg, for instance, 
get a copy of his public key and encrypyt the message with that.  
Then only a person who has the corresponding private key (hopefully 
Greg and Greg alone) can decipher it.  This raises the question of 
being damn-sure you get a copy of Greg's public key - not that of an 
imposter.  This leads to a discussion about public key authentication 
frameworks and the like.


I have just written the first half of a two part article on 
cryptography.  The first half is a tutorial on all this.  It isn't 
very complex - since I steer well clear of the weirdo mathematics 
which operate inside the algorithms.

This will appear in the September issue of Australian Communications.

The GAK (government access to keys) campaign is analogous to strong 
locks having been recently invented, and the government wanting a 
master key to every such lock which is produced - even though such 
locks can be ordered for free from overseas and any competent metal-
worker can create them from scratch using the well known techniques.

- Robin

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Robin Whittle     rw@firstpr.com.au  http://www.firstpr.com.au
                  Heidelberg Heights, Melbourne, Australia 

First Principles  Research and expression: music, Internet 
                  music marketing, telecommunications, human 
                  factors in technology adoption. Consumer 
                  advocacy in telecommunications, especially 
                  privacy. Consulting and technical writing. 

Real World        Electronics and software for music: eg.
Interfaces        the Devil Fish mods for the TB-303. 

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