When spark writes files to output destination, it writes files with the extension .crc (e.g: part-r-1.parquet.crc). How Apache Spark uses .crc files?
"CRCs are specifically designed to protect against common types of errors on communication channels, where they can provide quick and reasonable assurance of the integrity of messages delivered. However, they are not suitable for protecting against intentional alteration of data.
Firstly, as there is no authentication, an attacker can edit a message and recompute the CRC without the substitution being detected"
https://en.wikipedia.org/wiki/Cyclic_redundancy_check
It appears that Spark uses .crc files to ensure that the data in files transferred between nodes is intact. But I don't know how he uses it exactly