Arbitrum Nova vs Phala Network

Arbitrum Nova is a high-performance alternative to Arbitrum One's chain. While Arbitrum One implements the purely trustless Rollup protocol, Arbitrum Nova implements the mostly trustless AnyTrust protocol. The key difference between Rollup and AnyTrust is that the AnyTrust protocol introduces an additional trust assumption in the form of a Data Availability Committee (DAC). This committee (detailed below) is responsible for expediting the process of storing, batching, and posting child chain transaction data to Ethereum's parent chain. This lets you use Arbitrum in scenarios that demand performance and affordability, while Arbitrum One is optimal for scenarios that demand Ethereum's pure trustlessness.

Phala Network tackles the issue of trust in the computation cloud.