Which one of the guidelines below is not part of the Abadi-Needham Protocols Design Guidelines?

Question

Which one of the guidelines below is  not  part of the Abadi-Needham Protocols Design Guidelines?

Accepted Answer

All messages should be encrypted whenever possible.

Answer

Every message should say what it means, its interpretation should only depend on its content.

Answer

One should be clear on how the timeliness of messages is proven.

Answer

Any implicit assumptions in the protocol should be clearly spelled out.

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