ECDH
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Does each person keep their own secret private?
2. Is the secret ever sent to the other person?
3. Do you combine your own secret with the other person's shared piece?
4. Do both people end up with the same matching result?
5. Does each person have their own separate shared piece to give out?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1Combine your secret with their shared piece | AKeeping it private with its owner at all times | |
| 2Give out your shared piece | BThe outcome of each combining their own secret | |
| 3Both people reach the same matching result | CThis breaks security - the secret should never be sent | |
| 4The secret must never be sent to anyone | DSomething that is safe to do openly | |
| 5Sending your secret to the other person | EThis won't match - you need their shared piece instead | |
| 6Combining your secret with your own shared piece | FHow you reach the matching result |
C
Definitions
ECDH
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Each person keeps their own ______.
2.
Each person also gives out a shared _____.
3.
You _______
your secret with their shared piece.
4.
Both people end up with the same matching
______.
5.
The secret itself is never ____
to the other person.
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
Send secret to them
B
Keep secret private
C
Share your piece
Question 2
A
Keep secret private
B
Only you get the result
C
Both reach same result
Question 3
A
Keep secret private
B
Share your piece
C
Mix secret, own piece
Question 4
A
Keep secret private
B
Share your piece
C
Mix secret, their piece
D
Everyone shares one secret
Question 5
A
Keep secret private
B
Share your piece
C
Mix secret, their piece
D
Both reach same result
E
Secret shared too
Answer Key
ECDH
Section A: Quick Questions
Q1
A — Yes
Q2
A — No
Q3
B — Yes
Q4
A — Yes
Q5
B — Yes
Section B: Match the Pairs
Q1
Combine your secret with their shared piece → How you reach the matching result
Q2
Give out your shared piece → Something that is safe to do openly
Q3
Both people reach the same matching result → The outcome of each combining their own secret
Q4
The secret must never be sent to anyone → Keeping it private with its owner at all times
Q5
Sending your secret to the other person → This breaks security - the secret should never be sent
Q6
Combining your secret with your own shared piece → This won't match - you need their shared piece instead
Section C: Definitions
Q1
ECDH — A method where two people each combine their own secret with the other's shared piece, ending up with the same matching result without sending the secret.Section D: Fill in the Blanks
Q1
Each person keeps their own secret.Q2
Each person also gives out a shared piece.Q3
You combine
your secret with their shared piece.Q4
Both people end up with the same matching
result.Q5
The secret itself is never sent
to the other person.Section E: Spot the Error
Q1
A — Line 1 says to send your secret to them, but the secret must always stay private with its owner.
Q2
B — Line 2 says only you get the result, but both people end up with the same matching result.
Q3
C — Line 3 says to mix your secret with your own piece, but you should mix it with their piece instead.
Q4
D — Line 4 says everyone shares one secret, but each person keeps their own separate secret.
Q5
E — Line 5 says the secret is shared too, but only the piece should ever be shared, never the secret.