Hi,
I was mostly talking about the "fatal error" which was in HikaShop.
The warning you got is Joomla related and it as no relation with HikaShop, please see this with the Joomla community in the Joomla forum.
For what I see, the Joomla password hash (to hash the password in the database) can't access the the "urandom" of your web server. I am sure that it does not effect the rest of the process (it is not a "fatal error") but having a warning is always stressful.
Note that in production, you should not display PHP warning message.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.