Re: [Discuss-gnuradio] Out of Tree Encryption block

[Perper]

Hi all,

The system configuration proposed by Dushyant with encryption after
channel coding can work in case of stream ciphers. This is how it is
done in GSM. But encryption GSM is a very bad example of application of
cryptography. Channel coding will add some known relations between
information bits and it will be source weaknesses in the overall
cryptosystem.

Best Regards,
Piotr Krysik

W dniu 28.05.2014 22:45, Marcus Müller pisze:
> Hi Dushyant,
>
> A side note:
> I'm going to go assume that with "encoder" and "decoder" you mean
> Channel Coding.
> You *must* do channel coding after encryption, otherwise you won't get
> decryptable bits
> as soon as you don't have infinite SNR. This is not optional, because
> with proper
> encryption a single flipped bit will damage your signal in several places.
> This thread reminds me of
> http://lists.gnu.org/archive/html/discuss-gnuradio/2014-04/msg00277.html
> so there might a solution to your problem there; Ralph has posted some
> interesting insights
> back then.
>
> Usually, you'll want to have something that applies something like a
> block cipher on packetized data.
> Although I'm not aware of any existing Modules that do this, using
> stream tagged blocks, and the
> gr-digital header demux infrastructure, you should be able to packetize
> your data and encrypt the payload
> en bloc, for example using AES.
>
> Greetings,
> Marcus
>
>
> On 28.05.2014 15:25, dushyant.marathe wrote:
>> I want to simulate a voice transmission system in GNURadio Companion (GRC).
>>
>> My system configuration is as follows:
>>
>> TRANSMITTER : Wav file source --> encoder --> encryption --> modulator -->
>> RF  
>>
>> RECEIVER : speaker/Wav file sink <-- decoder <-- decryption <-- demodulator
>> <-- RF
>>
>> I have simulated the above configuration in Ubuntu 12.04  machine but
>> without
>> encryption/decryption blocks.
>>
>> If you can point me to an existing OoTM of digital encryption, it would be
>> nice.
>>
>> Thanks and Regards,  
>> Dushyant
>>
>>
>>
>> --
>> View this message in context: 
>> http://gnuradio.4.n7.nabble.com/Out-of-Tree-Encryption-block-tp48595.html
>> Sent from the GnuRadio mailing list archive at Nabble.com.
>>
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