What do you mean no paper trail? I thought Bitcoin worked by having a master list of EVERY transaction and then hashing the most recent for each new transaction.
This is from the Bitcoin doc [1]:
We define an electronic coin as a chain of digital signatures. Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner and adding these to the end of the coin. A payee can verify the signatures to verify the chain of ownership.