A confidential information exchange between a sender and a receiver may be conducted without the use of encryption keys. The information is coded with a Challenge-Response Table that is shared between the sender and the receiver. Rather than sending a challenge and then waiting for a response, the challenge and response are both sent by the sender of the information. The information sent comprises an index with a challenge and a response from the Challenge-Response Table. Upon receiving the coded information, the receiver uses the Challenge-Response Table to decode the information by using the index to locate the challenge and its valid response. Upon determining that the challenge and the response are correct, a first decoded answer is determined. Upon determining that either the challenge or the response, or both, are incorrect, a second decoded answer is determined.