Sheila has a customer called Fred. Fred wants to send Sheila a confidential document as part of a transaction. Explain how Fred uses asymmetric encryption to send his document securely.

Mark scheme

Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.

1. [4] MP1 Sheila's computer uses an algorithm to generate a matching pair of keys private and public
2. [4] MP2 Sheila's computer sends Fred's computer Sheila's public key // Fred's computer acquires Sheila's public key
3. [4] MP3 Fred's computer encrypts the document/plain text using Sheila's public key to create cipher text
4. [4] MP4 Fred's computer sends the cipher text to Sheila's computer The cipher text can only be decrypted using Sheila's private key // Sheila's computer uses Sheila's private key to decrypt the cipher text.