I am trying to build and patent an elliptic curve-based encryption device. I am very new on this field and my 1st thought is what should I take care of?? Are encryption algorithms like ECC open source, so that I can use them? Is it as easy as buying a security book and 'transform' the encryption algorithms to code?
Whether or not elliptic curve encryption is open source or not, there can still be patents. I did a search on Google Patents using the keywords "elliptic curve" and "encryption" and got more than 15,000 hits for granted patents. The number of US Patents is a slightly more manageable 5967.
Now it is quite possible that some of the patents are expired and others may have open source licensing which allows commercial use. Many more probably mention elliptic curve encryption as prior art but are patenting a different method. Figuring out freedom to operate would require a detailed analysis the patent art (including the even larger number of applications). Such an analysis would be beyond the scope of what I can provide. I would recommend reviewing the open source licensing terms for the software libraries you might use. Questions on licensing are off topic here but could be posted at the Law SE site.