"Paul" wrote:

Use the purported MD5 value, to guess at what
is being offered. Only accept an ISO, for which
an official SHA1 sum is offered. The MD5 can be
used for tracking tasks, but cannot be trusted for authentication.

SHA-1 isn't completely reliable either, but it's a lot better than MD5.

Popping the checksum into Google, gives these references.
What does "VL" stand for ? Bueller ?

The string "VL" in the ISO filename indicates that the image is for volume
license customers.

en_windows_8_1_pro_vl_x86_dvd_2972633
en_windows_8_1_pro_vl_x64_dvd_2971948

The filenames, including the image identifier at the end, match those of the
VL images offered from the MSDN download site.

Joe