This paper explores Time-Valid One-Time-Signature (TV-OTS) as a data authentication protocol for potential use in smart grid applications. TV-OTS is highly configurable with computationally lightweight signing and verification processes, making it a strong candidate for smart grid use. A detailed analysis of security against brute force attacks is presented, which is critical to understanding the parameters under which TV-OTS is reliably secure. This analysis is used to choose applicable parameters for latency tests of a full TV-OTS implementation. Performance results are favorable, with the cost of combined signing and verifying reaching under 10 milliseconds.