A one-time pad (OTP) based cipher to insure both data protection and integrity when mobile code arrives to a remote host is presented. Data protection is required when a mobile agent could retrieve confidential information that would be encrypted in untrusted nodes of the network; in this case, information management could not rely on carrying an encryption key. Data integrity is a prerequisite because mobile code must be protected against malicious hosts that, by counterfeiting or removing collected data, could cover information to the server that has sent the agent. The algorithm described in this article seems to be simple enough, so as to be easily implemented. This scheme is based on a non-interactive protocol and allows a remote host to change its own data on-the-fly and, at the same time, protecting information against handling by other hosts.