hashcat in VM

[undeath]

to get full speedup the best way would probably be:

(note: I'm assuming each key is 8 bytes; adapt as needed)

1. create a wordlist with all combinations of K1 (or a reproducable subset thereof if the whole space is too large)
2. create a ruleset which appends the bytes for K2 (you can chain rulesets, hence you only need a single rules file with one rule for each byte and use that eight times)
3. as a single final rule(set) use d]]]]]]]] (this will duplicate the whole candidate (K1+K2) and then remove K2 at the end)

so your files might look like this:

K1.txt (use --hex-wordlist)

Code:

0000000000000000
0100000000000000
0200000000000000
…
ffffffffffffffff

K2.rule

Code:

$\x00
$\x01
…
$\xff

final.rule

Code:

d]]]]]]]]

modifying the existing kernel to handle everything would be a nicer solution, but also not as easy to pull off.