File hash definition
A file hash, also known as a cryptographic hash, is a fixed-size string of characters that is generated by running the contents of a file through a mathematical algorithm. The resulting hash is unique to that file and can be used to verify its integrity because if even one bit of the file is changed, the resulting hash will be different. File hashes are commonly used in digital forensics, software distribution, and version control.
What are hash files used for?
- To verify that a file has not been corrupted or tampered with. By comparing the hash of a downloaded file with the original hash, a user can be sure that the file is exactly as it should be.
- To detect and remove duplicate files. Users can identify which files are identical by comparing the hashes of multiple files and automatically delete the copies.
- To identify and track specific files. By creating a hash of a file and comparing it to a database of known files, investigators can quickly determine if a file is relevant to an investigation.
- To track changes to files over time. By creating a new hash every time a file is modified, users can see what changes have been made and who made them.
See also: hashing, encryption, blockchain