On Friday, the Ethereum blockchain experienced a technical issue that caused it to stop finalizing blocks for over an hour, which is the second time in the past 24 hours. The cause of the incident is unknown, but it raised concerns about security for users of the second-largest blockchain by market capitalization. When blocks are not being finalized, pending transactions may be re-ordered or dropped from the network. Although the network had resumed finalizing blocks at press time, some services built on top of Ethereum had to modify their operations due to the lack of finality.