Using public key cryptography, X adds a digital signature σ to a message M,…
2017
Using public key cryptography, X adds a digital signature σ to a message M, encrypts (M,σ) and sends it to Y, where it is decrypted. Which one of the following sequence of keys is used for operations?
- A.
Encryption : X’s private key followed by Y’s private key. Decryption : X’s public key followed by Y’s public key.
- B.
Encryption : X’s private key followed by Y’s public key; Decryption : X’s public key followed by Y’s private key
- C.
Encryption : X’s private key followed by Y’s public key; Decryption : Y’s private key followed by X’s public key.
- D.
Encryption : X’s public key followed by Y’s private key; Decryption : Y’s public key followed by X’s private key.
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Correct answer: C
In public key cryptography, digital signatures are created using the sender's private key to ensure authenticity. To ensure confidentiality during transmission, the message and signature are encrypted using the recipient's public key. Upon receipt, the recipient decrypts the data using their own private key and verifies the signature using the sender's public key.
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