File hash (MD5, SHA1, SHA256) enrichment refers to the process of using a file's hash value to identify and gather additional information about the file. A file's hash value is a unique string of characters that is generated based on the contents of the file. By comparing a file's hash value to a database of known hash values, it is possible to determine whether the file has been seen before and, if so, to gather additional information about it, such as its source and whether it is known to be malicious. This can be useful for identifying and mitigating potential security threats.