[En-Nut-Discussion] scp sftp or ssh for Ethernut (1.3 Board)

[Ralph Mason]

Google is your friend

http://www.ftp.cl.cam.ac.uk/ftp/papers/djw-rmn/djw-rmn-tea.html

Or in C

void encipher(const unsigned long *const v,unsigned long *const w,
   const unsigned long * const k)
{
   register unsigned long       y=v[0],z=v[1],sum=0,delta=0x9E3779B9,n=32;

   while(n-->0)
      {
      y += ((z << 4 ^ z >> 5) + z) ^ (sum + k[sum&3]);
      sum += delta;
      z += ((y << 4 ^ y >> 5) + y )^ (sum + k[sum>>11 & 3]);
      }

   w[0]=y; w[1]=z;
}

void decipher(const unsigned long *const v,unsigned long *const w,
   const unsigned long * const k)
{
   register unsigned long       y=v[0],z=v[1],sum=0xC6EF3720,
                delta=0x9E3779B9,n=32;

   /* sum = delta<<5, in general sum = delta * n */

   while(n-->0)
      {
      z -= ((y << 4 ^ y >> 5) + y) ^ (sum + k[sum>>11 & 3]);
      sum -= delta;
      y -= ((z << 4 ^ z >> 5) + z) ^ (sum + k[sum&3]);
      }
  
   w[0]=y; w[1]=z;
}


> Dear Ralph,
> thank you for that hint, about TEA.
> Do you know where i can find source code?
> Or can you contribute the code to the community?
> Rgd´s Roland
>
>   
>> --- Ursprüngliche Nachricht ---
>> Von: Ralph Mason <ralph.mason at telogis.com>
>> An: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
>> Betreff: Re: [En-Nut-Discussion] scp sftp or ssh for Ethernut (1.3 Board)
>> Datum: Fri, 02 Dec 2005 08:30:37 +1300
>>
>> I found that TEA works well on a AVR. For distributing keys you can use 
>> RSA give your server a private key, and then encrypt a 128 bit session 
>> key with the public key during programing of each device.  (A different 
>> one for each device clearly!)
>>
>> Then you device can tell the server it's session key, use TEA (or other 
>> for the session) and there is no problem keeping hold of lists of them.
>>
>> Ralph
>>
>>
>>     
>>> Dear Vesa,
>>> Thank you for your quick response.
>>>
>>> I found sources for BLOWFISH at 
>>> http://www.schneier.com/blowfish-download.html
>>> So i can encrypt the data before sending with ftp.
>>>
>>> Does anyone have a hint, where to find sources or information,
>>> if i want to do it with "predistributed keys" ?
>>>
>>> rgdßs roland
>>>
>>>
>>>   
>>>       
>>>> --- Ursprüngliche Nachricht ---
>>>> Von: Clemens Kirchgatterer <c.kirchgatterer at amatic.com>
>>>> An: "Ethernut User Chat (English)" <en-nut-discussion at egnite.de>
>>>> Betreff: Re: [En-Nut-Discussion] scp sftp or ssh for Ethernut (1.3
>>>>         
>> Board)
>>     
>>>> Datum: Thu, 1 Dec 2005 11:51:41 +0100
>>>>
>>>> Vesa Jääskeläinen <chaac at nic.fi> wrote:
>>>>
>>>>     
>>>>         
>>>>> r.j.pieper at gmx.net wrote:
>>>>>       
>>>>>           
>>>>>> Hello Everyone,
>>>>>>
>>>>>> does anybody know how to implement or where to find code for scp,
>>>>>> sftp or ssh?
>>>>>>
>>>>>> Any help or hints are welcome.
>>>>>>         
>>>>>>             
>>>>> That might be a quite a job to implement those yourself ;), but you
>>>>> can use OpenSSH as a reference:
>>>>>       
>>>>>           
>>>> i think performance wise, this is not feasable. all that bignum
>>>> operations in rsa are just too cpu hungry.  i would go for
>>>> predistributed keys and blowfish.
>>>> _______________________________________________
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>>>>
>>>>     
>>>>         
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>>>   
>>>       
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