[openssl-users] RSA Key generation time

Jakob Bohm jb-openssl at wisemo.com
Tue Jan 17 16:08:57 UTC 2017

On 17/01/2017 07:44, Mithun P wrote:
> Hi
> I have a embedded board P1010 RDB  running openssl on VXWORKS 5.4 .
> I am generating RSA 2048 and 3072 bit key pairs.
> I am providing entropy to openssl by using RAND_seed from a HW RNG.
> My average generation time for RSA 2048 key pair is 2 Minutes and 
>  3072 is 8 minutes.
> Is there a way to reduce the generation time?
I believe this is a CPU intensive operation (if VxWorks can do
this, try observing the CPU load during).

Potential improvements:

1. Check if the CPU specific bignum optimizations for your CPU
   variant have been enabled via the libcrypto CPU detection code
   (for example, there are optimizations for different ARM cortex
2. Faster CPU (expensive obviously).
3. Do the generation in the background before the keypair is
   needed, at a time when the extra CPU load is less of a problem.


Jakob Bohm, CIO, Partner, WiseMo A/S.  https://www.wisemo.com
Transformervej 29, 2860 Søborg, Denmark.  Direct +45 31 13 16 10
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