What network is IoTeX on?

As a seasoned individual in the realm of cryptocurrency and finance, I'm curious to inquire about the underlying network that IoTeX operates on. Could you elaborate on the technological foundation that IoTeX leverages to power its decentralized ecosystem? Specifically, I'm interested in understanding if IoTeX is built on an existing blockchain infrastructure, such as Ethereum, or if it utilizes a proprietary blockchain technology. Additionally, I'd appreciate any insights into the scalability, security, and interoperability aspects of the IoTeX network.