[Info-vax] What to do with my VAX.....

[Arne Vajhøj]

On 11/11/2020 10:40 PM, Dave Froble wrote:
> On 11/11/2020 9:12 PM, Bill Gunshannon wrote:
>> On 11/11/20 8:54 PM, Dave Froble wrote:
>>> On 11/11/2020 6:56 PM, Alexander Schreiber wrote:
>>>> seasoned_geek <roland at logikalsolutions.com> wrote:
>>>>> ALL
>>>>> ENCRYPTION is security by obscurity. Period.
>>>>
>>>> Thus proving nicely that you know _absolutely_ nothing about 
>>>> encryption.
>>>> You imight want to read up on Kerckhoff's principle for starters.
>>>
>>> Well, I wouldn't be so quick to dismiss that statement.
>>>
>>> Isn't not knowing a solution a form of obscurity?  Otherwise, if one
>>> knows the key, then there is no security, right?  So not knowing the
>>> key is sort of "security by obscurity"?
>>>
>>> There have been multiple instances in the past of codes being broken
>>> and harmful affects because of that.  The Japanese code in WWII?
>>>
>>> What is a "secret key", other than "unknown data"?  Can such a key be
>>> guessed?  Unlikely.  But possible.
>>>
>> Guess it depends on which part of ENCRYPTION you are talking about.
>> The entire algorithm for the Unix Password encryption is documented
>> and available for anyone who wants to read it.  No obscurity involved
>> at all.  Let me know when you figure out how to reverse the encryption
>> for any password.  Brute force doesn't count.
> 
> But, it would be possible, however very unlikely, to guess?  Or is that 
> considered "brute force"?

AES 256 bit has 2 power 256 possible keys.

That means that at average one will need to try 2 power 255 keys
before finding the correct one.

But one could be lucky and find it at first guess. Probability is
1 out of 2 power 256 for that happening.

Such odds are considered acceptable.

Arne