I don't know what you mean by "audit the message." Without third-party timestamping or blockchain, the same token can be sold to multiple buyers, and nothing c

I don't know what you mean by "audit the message." Without third-party timestamping or blockchain, the same token can be sold to multiple buyers, and nothing can be used to determine which buyer is the first ("real") buyer. This is the whole reason blockchain was invented. It wasn't possible to do it at all before that.