A protocol for prohibiting non-repudiation by transacting parties involved in an executed electronic transaction, whereby a trusted third party is responsible for ensuring non-repudiation. In this protocol, a sender uses a secret sharing technology to divide the original session key into a first sub-session key and a second sub-session key. The first and second sub-session keys must be combined into the original session key in order for a recipient to decrypt a product that is encrypted with the original session key. The sender includes the first sub-session key that is encrypted with a recipient's public key and an encrypted product in a first message. Then the sender transmits the first message to the recipient. The recipient uses the first message as evidence of non-repudiation of origin, i.e., evidence of non-repudiation that the sender sent the transaction. The recipient transmits, to the sender, a second message requesting the second sub-session key. The sender may use the second message as evidence of non-repudiation of receipt, i.e., evidence of non-repudiation that the recipient received the transaction. Thereafter, the sender includes the second sub-session key which is encrypted with the trusted third party's public key in a third message that is forwarded to the trusted third party.