Disregard Frap.doc's FUD.  Acquire primary sources:

https://github.com/ElementsProject/elements

https://people.xiph.org/~greg/blockstream.gmaxwell.elements.talk.060815.pdf

https://youtu.be/9pyVvq-vrrM   SF Bitcoin Devs: Bringing New Elements to Bitcoin with Sidechains (Greg Maxwell)

https://people.xiph.org/~greg/confidential_values.txt