Quiz

Gestapo agents can corrupt any single bit of a transaction.

"Corrupt" = change a bit to its opposite value?

The length of a transaction cannot exceed 7 bits.

Can it be split into several smaller transactions, so that in total there are 7 bits (or less)?
If the answer to all questions is "yes", then all four bits should be transmitted one by one, and Alex can change the value of the bits to the opposite and read them. However, on the other hand, it is not necessarily true that the Germans will corrupt this bit; the wording says that they "may"...