ITPEC FE Morning October 2023 Question 36
ITPEC FE Morning October 2023 — Question 36 of 80
Asymmetric encryption (public key cryptography) — identifies which private key is used to decrypt a message in asymmetric encryption.
In asymmetric (public-key) encryption, each person has a key pair: a public key (shared openly) and a private key (kept secret).
To send a confidential message to Mr. B:
- Mr. A encrypts the message using Mr. B's public key
- Only Mr. B's private key can decrypt it
This ensures only the intended recipient can read the message.
Why not others:
- (a) A third party has no role in decryption — only the recipient's private key works
- (b) Mr. A's private key is not involved in decryption; it would only be used if Mr. A were signing the message
- (c) Mr. A's private key cannot decrypt a message encrypted with Mr. B's public key
Key rule: Encrypt with the recipient's public key → decrypt with the recipient's private key.
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