Self Introduction

Jan Tulak jtulak at redhat.com
Tue Jan 7 10:00:25 UTC 2014


On Monday 06 of January 2014 16:42:35 Miloslav Trma─Ź wrote:
> I appreciate that you needed to write a tool like this for the thesis;
> for general usage I'd strongly urge everyone to use a general-purpose
> cryptographic library that doesn't promise to use a particular
> technology.  We really want the ability to disable a
> broken/suspicious/problematic random number source by only patching a
> few cryptograhic libraries, without having to individually modify
> various applications.
>     Mirek

I understood your worrying, but I think we have different use-cases on our 
mind.

I'm not aiming to replace OpenSSl or something. Anyone can use the RdRand 
already (if one has the HW) so I'm trying to provide a better interface for 
those who would probably use the RdRand even without my library - this will 
make their work easier and more secure, as they do not need to re-implement it 
on their own with new bugs.

The RdRand can be securely used for things like erasing HDD before further 
encryption and so, by command like:

rdrand-gen | dd iflag=fullblock of=/dev/sda bs=4k

And I believe that if RdRand is used in combination with AES and some good 
random key, some possible weakness in RdRand is effectively dismissed:

rdrand-gen | aespipe -v -P <(head -n 3705 /dev/random | uuencode -m - | head -
n 66 | tail -n 65) | cat -A

This will harden the RdRand output with aespipe. Aespipe will use keyfile based 
on /dev/random and encrypt rdrand-gen output. It will mitigate any 
back-door possibly built into RdRand. The speed of this solution on my machine 
is up to 300 MiB/s. :-)

Regards
Jan


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