Tinker4 messages in the open: 8 lost.In the open: PRICES ✗, BANK ✗, DELIVERY ✗, CODE ✗
Chapter 7 of 7
Lock, sign or both
Brightwater is a trusted supplier now. Four of its messages cross the line, and three attackers wait on it.
This chapter: Which messages need a lock, which a signature, and which both?
About this chapter
You will learn
- Lock what must stay secret
- Sign what must be genuine
- Never lock what everyone must read
Words you’ll meet
- Attacker
- Anyone on the line: one reads, one changes, one pretends to be the supplier.
Step 1 of 2
Each waits on the line: one reads, one changes, one fakes the sender.
Pick lock, sign or both for each message.
8 lost · the best loses nothing NOT YET
| Message | Sent | Lost |
|---|---|---|
| Price list for every shop | Send it as it is | Tamperer changes it; Impostor fakes it |
| New bank details | Send it as it is | Eavesdropper reads it; Tamperer changes it; Impostor fakes it |
| Delivery date | Send it as it is | Tamperer changes it; Impostor fakes it |
| Larkspur’s own discount code | Send it as it is | Eavesdropper reads it |
The messages and attackers are written for this site.