From: sto.mar@...
Date: 2012-07-26T22:40:29+09:00
Subject: Re: modular exponentation with multiple exponents?

Am 25.07.2012 23:21, schrieb roob noob:
> Jan E. wrote in post #1070171:
>> Half baked security is probably even worse than no security at all,
>> because it provides you with a false feeling of safety.
>
[...]
>
> I found the answer to my question, it is asking for
>
> ((((a ^ b) mod f) ^ c) mod f)) ^ d) mod f) etc (something I thought may
> be the case, although I was by no means sure)
>
> which is equal to a^b*c*d*etc mod f (which is probably how I should have
> read it in the first place, doh)

What you probably really mean is: a^(b*c*d*...) mod f

You should be aware of the fact that (in Mathematics as well as in Ruby)
2^3*4 and 2^(3*4) [resp. 2**3*4 and 2**(3*4)] are *not* the same.
Which kind of supports the point Jan is making.

Btw, there is also a huge(!) difference between 2**3**4 = 2**(3**4)
and (2**3)**4.

> anyway I apologize for a question that had only a minor relation to
> Ruby, however I do think you are wrong to think that a well researched
> project implemented from a spec and reviewed by professionals will
> certainly end up being worse than a project made by someone who has
> already done the research to become a professional.

Regards,
Marcus


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