Symmetric key security protocols:

Symmetric key security protocols:
Please use the given and your defined notation and tools and design security protocols for the following settings:

a) A wireless sensor node, A, is required to provide periodically measurements to a device within range, B. The two share a symmetric key. Each message sent by A contains a single measurement. B needs to verify the origin authenticity of each message.

b) In the same setting as above, consider a period over which multiple measurements are sent by A. Now, B needs to verify the authenticity and integrity of this sequence of measurements. At first, assume that tAc l ock = tBc l ock throughout this period.

c) In the previous setting, assume that the clock of A cannot be synchronized with that of B. Again, B needs to verify the authenticity and integrity of this sequence of measurements.

d) As an additional requirement, B needs to ensure that all measurements of A are confidential.

e) In the previous setting, now B needs A to use different symmetric keys for ensuring confidentiality and authenticity. Let those be KcAB and KaAB respectively and assume that those are available at A and B.

f ) Without re-writing the protocol you devised for the previous setting: How can you handle a situation that A and B have only one shared key for authentication but they decide to use a second one for confidentiality?