Secrecy and user trust

[Ed Greshko]

Bill Davidsen wrote:
> Ed Greshko wrote:
>> Bill Davidsen wrote:
>>> Ed Greshko wrote:
>>>> Patrick O'Callaghan wrote:
>>>>> The hypothetical scenario being discussed is that you have already
>>>>> replaced the former (good but now possibly suspect) public key with a
>>>>> spurious new one. If that were to happen, you would be in danger of
>>>>> accepting trojanned packages signed with this new fake key. My
>>>>> point is
>>>>> that you would also *reject* packages signed with the new good
>>>>> key, and
>>>>> this would be noticed very quickly (basically the next time you
>>>>> did an
>>>>> update).
>>>>>   
>>>> That is an extremely unlikely possibility as you have to generate a
>>>> key
>>>> with the same key id (fingerprint)as the original.  Also, you have to
>>>> determine how to trick all users in to replacing the original.
>>> All users? This is like spam email, you only need to succeed in a few
>>> cases to get benefit. And distributing the fingerprint assumes you can
>>> do that securely as well.
>>>
>> I think you have no concept of public/private encryption or signing.
>>
> My concept is that if I can fool you into accepting a false public
> key, I can sign packages with the matching false private key, and when
> you install the first such package it may (probably will) include evil
> things of some nature.
>
> Do you disagree? Or feel that if I can get you to run one evil package
> I can't put in a root kit, or rend personal information from your
> systems, or otherwise attack your system?
>
> If you feel that line of attack is not possible do tell me how your
> concept of encryption and signing prevents it.
>
I thought you were talking "real world" as opposed to purely hypothetical.

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