A system for creating a log of a conversation includes a convener computer and a plurality of conversation computers interconnected by a computer network. The system includes an arbiter computer and a plurality of conversation computers interconnected by a computer network. The arbiter computer creates a public key pair comprising a new public key and a new private key, and causes the new public key to be transmitted to the conversation computers. The conversation computers receive the public key and transmit messages during the conversation. The arbiter computer uses the new private key to encrypt messages transmitted by at least some of the conversation computers during a conversation among the conversation computers, and to store the encrypted messages in a message log. The conversation computers cause messages in the message log to be decrypted using the new public key.