A method for protecting a message or document. The method comprises encrypting the message using a first key associated with a first party; sending the encrypted message to a second party; encrypting the message using a second key associated with the second party, so that it is encrypted with two keys simultaneously; sending the encrypted message to the first party; decrypting the message using the first key; sending the message to the second party, the message being encrypted with the second key, and using the second key to decrypt the encrypted message, thereby exposing the original message.