If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

Main content

Symmetric encryption


Herman came up with a scheme for encrypting messages to send to his best friend:
For each letter in the message, he replaces the letter with a picture that represents that letter.
He needs to share the encryption key with his friend before they can decrypt his messages.
What would be the best key for this symmetric encryption scheme?
Choose 1 answer: