Three people (Anders, Anna, and Lena) want to communicate safely. They want to use symmetric encryption and see the need to exchange new keys daily. Dedicated keys are used between all communicating parties, one key to communicate between Anders and Anna, and another key between Anna and Lena, so three symmetric keys are needed. Asymmetric encryption is used for the distribution of symmetric keys. Diffie-Hellman key exchange is considered risky due to the man-in-the-middle threat, so some of the communicating parties need to propose the symmetric key to use for a specific day and share it using asymmetric encryption. The proposed symmetric key should, of course, only be available for the communicating peers, and it must be possible to verify the originator suggesting the key. Further, X.509 certificates are used for the distribution of public keys. Your task is to present a solution that meets the security requirements by proposing what algorithms to use to provide the security needed considering today’s state-of-the-art technologies, the message exchange required, and list what key lengths you see as feasible
Three people (Anders, Anna, and Lena) want to communicate safely. They want to use symmetric encryption and
see the need to exchange new keys daily. Dedicated keys are used between all communicating parties, one key to
communicate between Anders and Anna, and another key between Anna and Lena, so three symmetric keys are needed.
Asymmetric encryption is used for the distribution of symmetric keys. Diffie-Hellman key exchange is considered risky
due to the man-in-the-middle threat, so some of the communicating parties need to propose the symmetric key to use
for a specific day and share it using asymmetric encryption. The proposed symmetric key should, of course, only be
available for the communicating peers, and it must be possible to verify the originator suggesting the key. Further,
X.509 certificates are used for the distribution of public keys. Your task is to present a solution that meets the security
requirements by proposing what
technologies, the message exchange required, and list what key lengths you see as feasible.
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