# Hash Values

To guarantee integrity, hash values should be stored.

* Hash blocks of small size to prevent a single error to invalidate all drive images.
  * e.g. the same size as the acquisition block.
* In a RAW file; hash values are stored in a separate file.
* **It is always recommended to do a digital signature on the hash values files.**
  * Why do you think this is good practice?

Digital signatures.

* The best tool is [GnuPG](https://www.gnupg.org/).
* If possible, use also a time-stamping server.