Explanation
The main purpose of creating and storing an external disk hash value when performing forensic data acquisition from a hard disk is to validate the integrity of the data during the analysis. This is done by comparing the original hash value of the disk to the hash value created during the acquisition process, which can be used to ensure that the data has not been tampered with or corrupted in any way. Additionally, by creating a hash value of the disk, it can be used to quickly verify the integrity of any data that is accessed from the disk in the future.

Explanation
The primary advantage of single sign-on (SSO) is that it increases the efficiency of access management. With SSO, users only need to remember one set of credentials to access all of their applications, rather than having to remember multiple usernames and passwords for each application. This simplifies the user experience and helps to reduce the amount of time spent managing access to multiple applications. Additionally, SSO can also increase the security of related applications, as users are not sharing the same credentials across multiple applications, and it can also support multiple authentication mechanisms, such as biometric authentication.