FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Salsa20

 
Post new topic   Reply to topic     Forum Index -> dcrypt
View previous topic :: View next topic  
Author Message
bobef



Joined: 05 Jun 2005
Posts: 269
PostPosted: Sat Feb 21, 2009 12:31 pm    Post subject: Salsa20 Reply with quote
Hi, I see dcrypt is updated with new ciphers. That's great, thank you for your efforts! I read somewhere about this Salsa20 cipher, that you could seek to any position in the stream. Is it so and does dcrypt support this functionality?

Thanks,
bobef
Back to top
View user's profile Send private message
reikon



Joined: 31 Jul 2008
Posts: 7
PostPosted: Sun Feb 22, 2009 2:36 am    Post subject: Re: Salsa20 Reply with quote
bobef wrote:
Hi, I see dcrypt is updated with new ciphers. That's great, thank you for your efforts! I read somewhere about this Salsa20 cipher, that you could seek to any position in the stream. Is it so and does dcrypt support this functionality?

Thanks,
bobef


Thanks for keeping watch Smile

That feature of Salsa20 isn't currently supported by dcrypt in an exposed interface (meaning it's only possible by subclassing Salsa20 and modifying the state array appropriately), but could be made available upon request. I could add a "void seek(long n)" method to the StreamCipher class to be implemented by all stream ciphers, if you'd like.

Thanks again for your continued interest!
Back to top
View user's profile Send private message
bobef



Joined: 05 Jun 2005
Posts: 269
PostPosted: Sun Feb 22, 2009 3:15 am    Post subject: Reply with quote
I think it would be very useful to have seek method. It could be used even with block ciphers. In one of my projects I'm using blowfish and I'm using seeking. For example - encrypted video stream. In this case (and in others too) you want seeking and you don't want to download and/or decrypt the whole thing. This of course depends on the ... I don't know what it is called - this CBC MBC SMS thing Smile When the next block depend on the previous. By the way, I'm looking forward to switching to dcrypt and maybe Salsa20 for this project.
Back to top
View user's profile Send private message
reikon



Joined: 31 Jul 2008
Posts: 7
PostPosted: Sun Feb 22, 2009 3:37 am    Post subject: Reply with quote
bobef wrote:
I think it would be very useful to have seek method. It could be used even with block ciphers. In one of my projects I'm using blowfish and I'm using seeking. For example - encrypted video stream. In this case (and in others too) you want seeking and you don't want to download and/or decrypt the whole thing. This of course depends on the ... I don't know what it is called - this CBC MBC SMS thing Smile When the next block depend on the previous. By the way, I'm looking forward to switching to dcrypt and maybe Salsa20 for this project.


Unfortunately a seek() method could only be used with stream modes of operation with block ciphers, like CTR. You wouldn't be able to do similarly with CBC.

I'll look into implementing a seek() method for stream ciphers and maybe in ManagedBlockCipher for block stream modes (CTR, currently).
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> dcrypt All times are GMT - 6 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group