02-09-2017, 01:18 AM

(02-09-2017, 12:46 AM)ccprime Wrote: XOR is not supported by hashcat, i think

Sorry if I made that hard to understand, the XOR is performed at the end of the encryption to obtain the cipher that is transmitted. I manually XOR the encryption outputÂ with the plain text to show that it produces the same cipher text as a straight DES-OFB encryption.

To obtain the encrypted text necessary for the Hashcat function you need to XOR the cipher text with the Known plain text. But that will only give the encrypted text for the first byte of each cycle.

This diagram may help to explain the encryption process

I cant seem to work out how to get a complete 8 bytes of encrypted text to be able to run the Hashcat DES option. As the final cipher text has one byte of output from each DES encryption cycle.

As I said earlier, I only need to find the key for any stage of the cycle as the same key is used everytime. I know the input text in full for all stages and the first byte of encrypted text for every stage.

Is it even possible to find the key in DES-OFB even if you know the plain text?