On Sun, Apr 08, 2018 at 07:39:30AM +0200, Richard Levitte wrote: > In message <20180407190250.ga27...@roeckx.be> on Sat, 7 Apr 2018 21:02:51 > +0200, Kurt Roeckx <k...@roeckx.be> said: > > kurt> On Sat, Apr 07, 2018 at 06:49:50PM +0200, Richard Levitte wrote: > kurt> > Hmmmm... case 4 shouldn't pose too much problems unless you restart > kurt> > the application more than once every second or so (for a 1 second > kurt> > resolution). On VMS, the system time is kept with 100 nanosecond > kurt> > granularity... this doesn't mean that it's actually updated every 100 > kurt> > nanosecond, but the possibility is there when VMS runs on fast enough > kurt> > hardware (a VAX is decidedly not in that range, Alpha has a minimum > kurt> > update rate of 1ms, Itaniums are faster than most Alphas...). Either > kurt> > way, the timestamp is 64 bits, it seems that then, we'd add a 64-bit > kurt> > counter to match the 128 bit nonce requirement, do I get that right? > kurt> > kurt> The requirement is not to have it 128 bit. Just that it doesn't > kurt> repeat as often as a 128 random number. You're most likely not > kurt> going to instantiate it 2^64 times. As long as the combination is > kurt> unique, it should be fine. > > "The requirements" depend on where you look. Looking at the code, or > more specifically drbg_ctr_init in drbg_ctr.c, about line 421, I see > this: > > drbg->min_noncelen = drbg->min_entropylen / 2; > > So the DRBG CTR code currently requires 128 bits minimum by default, > unconditionally.
The standard does not require this 128 bit. This 128 bit is only required for the random value. The example even has a nonce of 32 bit. Kurt _______________________________________________ openssl-project mailing list email@example.com https://mta.openssl.org/mailman/listinfo/openssl-project