File signature

In computing, a file signature is data used for identify or verify the content of a file. In particular, it may refer to:

* File magic number: bytes within a file used to identify the format of the file; generally a short sequence of bytes (most are 2-4 bytes long) placed at the beginning of the file;
* File checksum or more generally the result of an hash function over the file content: data used to verify that the file content integrity, generally against transmission errors or malicious attacks. The signature can be included at the end of the file or in a separate file.

ee also

* Signature file
* Virus signature