Dell Precision M4500 Administrator's Manual page 58

After selecting desired Hash Algorithm, you are prompted to type the certificate hash value.
The Certificate hash value is a hexadecimal number (for SHA-1 it is 20 bytes for SHA-2 it is 32 bytes). If the value is not
entered in the correct format, the message "Invalid Hash Certificate Entered - Try Again" is displayed. When you press
<Enter>, you are prompted to set the active state of the hash.