Asymmetric encryption
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Asymmetric encryption uses two different but mathematically linked keys.
2. Which key should be shared openly: the public key, or the private key?
3. The private key can be shared openly without any risk to security.
4. Which decrypts data encrypted with the public key: the matching private key, or the same public key?
5. Asymmetric encryption requires both parties to share the same secret key beforehand.
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1ct = encrypt(msg, pub) | AThe mistake: decrypting with the public key instead of the private key | |
| 2pt = decrypt(ct, priv) | BDecrypting data using the matching private key | |
| 3Asymmetric encryption uses a linked pair of keys | CEncrypting data using the recipient's public key | |
| 4The public key can be shared openly without weakening security | DThe mistake: sharing the private key, which must stay secret | |
| 5share_publicly(priv) | Eshare_publicly(pub) | |
| 6pt = decrypt(ct, pub) | Fpub, priv = generate_key_pair() |
C
Definitions
Asymmetric encryption
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
__________ = get_public()
2.
___________ = get_private()
3.
ct = ____________(msg, public_key)
4.
pt = ____________(ct, private_key)
5.
def _________________():
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
pub = get_public()
B
priv = get_private()
C
ct = encrypt(msg, priv)
Question 2
A
pub = get_public()
B
priv = get_private()
C
ct = encrypt(msg, pub)
D
pt = decrypt(ct, pub)
Question 3
A
pub = get_public()
B
keep_secret(pub)
C
priv = get_private()
Question 4
A
priv = get_private()
B
share_publicly(priv)
C
pub = get_public()
Question 5
A
pub = priv
B
ct = encrypt(msg, pub)
C
pt = decrypt(ct, priv)
Answer Key
Asymmetric encryption
Section A: Quick Questions
Q1
A — True
Q2
B — Public key
Q3
A — False
Q4
A — The matching private key
Q5
B — False
Section B: Match the Pairs
Q1
ct = encrypt(msg, pub) → Encrypting data using the recipient's public key
Q2
pt = decrypt(ct, priv) → Decrypting data using the matching private key
Q3
Asymmetric encryption uses a linked pair of keys → pub, priv = generate_key_pair()
Q4
The public key can be shared openly without weakening security → share_publicly(pub)
Q5
share_publicly(priv) → The mistake: sharing the private key, which must stay secret
Q6
pt = decrypt(ct, pub) → The mistake: decrypting with the public key instead of the private key
Section C: Definitions
Q1
Asymmetric encryption — Encryption that uses a linked pair of keys: a public key to encrypt data and a private key to decrypt it, with no shared secret key needed.Section D: Fill in the Blanks
Q1
public_key = get_public()Q2
private_key = get_private()Q3
ct = asym_encrypt(msg, public_key)Q4
pt = asym_decrypt(ct, private_key)Q5
def generate_key_pair():Section E: Spot the Error
Q1
C — Line 3 encrypts using the private key, but asymmetric encryption should encrypt with the public key.
Q2
D — Line 4 decrypts using the public key, but decryption should use the matching private key instead.
Q3
B — Line 2 treats the public key as secret, but the public key is meant to be shared openly.
Q4
B — Line 2 shares the private key publicly, but the private key must stay secret to remain secure.
Q5
A — Line 1 sets the public key equal to the private key, but they must be a distinct, linked pair.