Hi,
It is a little mix. HikaShop have options to force SSL on the checkout but it role is quite limited about PCI compliance.
The server must have a SSL certificate if you want to receive credit card information, the server have to be secured too.
The plugin will read this data, use it for his purpose (communication with the payment service, like Authorize.net) and erase the data when finished.
HikaShop does not use or store this data. The software itself is secured and it have been audited by Compass Security AG.
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.