A SSD VPS is usually hosted on a dedicated server or a cluster of dedicated servers using RAID SSD Drives, while a Cloud server is still a virtual server hosted on several dedicated servers and is fully redundant to hardware failure. While a classic VPS might not be as fault tolerant regarding hardware it will survive a disk failure due to the raid array.
When it comes down to the hosting industry its a world with its own terminology and should be taken with a pinch of salt. Most of the "Cloud Servies" offered on the market are just regular VPS services, the term has been overused and given to basicly anything nowadays.
SSD VPS means the your VPS is powered by SSD drives.
Cloud VPS means your VPS is powered by a stack of hyper visors that have fail over protection so the risk of a hardware failure is almost impossible, however as @hostbastic said the term "cloud" does not mean much anymore as people use it for everything but the way I have defined it is the technical definition of a cloud which also has other advantages than just failure protection.
I think that ssd vps could be faster and better for the performance. But what about the security? is there any difference between those two? is there any advantages for the cloud vps over the ssd vps? any help would be much appreciated!
If your're referring to Cloud VPS's as HDD VPS's, then, with SSD VPS's, you get much faster I/O speeds, and a little increase in performance. I don't think there is necessarily a increase in security though.