Asymmetric Encryption & Digital Signatures
by Froga
Why public-key cryptography needs two keys, which one does what, and how running the pair backwards turns encryption into a signature.
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Study material
The rule is that a message is locked with the key of whoever should be able to open it. Encrypting with Bob's public key means only Bob's private key can decrypt it — and since the public key can be handed to anyone, nothing secret has to travel before the conversation starts. That is the problem symmetric encryption cannot solve on its own.
Alice wants to send Bob a confidential message using public-key cryptography. Which key does she encrypt it with?
multiple choice
Bob's public key
Bob's private key
Alice's public key
Alice's private key
Only one person should be able to open it. Whose key must it be?
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