How do routing protocols like OSPF and RIP contribute to efficient data routing in IP networks?

What is the relationship between corresponding layers at the source and destination nodes of a TCP/IP communication connection

Suppose you are a judge trying to decide a dispute between a buyer and a supplier. The buyer claims not to have produced a particular email purchase order, while the supplier shows you the purchase order, and certificates and CRLs (Certificate Revocation Lists), demonstrating that the purchase order was signed by the buyer. All documents have been signed by a notary. How would the dates on the various pieces of evidence influence your decision? What if only the purchase order was signed by the notary?