DES with partial plain text
I have a problem with recovering a DES password using Hashcat when I only know the first six bytes of the plaintext.
The plain text is say 11 22 33 44 55 66 xx xx
I know the full cipher text.

I understand that the source code needs to be patched to "white out" some bits corresponding to the unknown, two last bytes.
Then when hashcat is run using  "--keep-guessing" it will find many false positives. I can then examine them manually to find the full plain text.  

I'm only a beginner in C so I do not know which bits to "white-out". I guess the modules in question are cpu_des.c and cpu.des.h ?

Can anyone help me with this, please?
Thanks in anticipation.