RFC 1805 (rfc1805) - Page 1 of 6


Location-Independent Data/Software Integrity Protocol



Alternative Format: Original Text Document



Network Working Group                                           A. Rubin
Request for Comments: 1805                                      Bellcore
Category: Informational                                        June 1995


         Location-Independent Data/Software Integrity Protocol

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This memo describes a protocol for adding integrity assurance to
   files that are distributed across the Internet.  This protocol is
   intended for the distribution of software, data, documents, and any
   other file that is subject to malicious modification.  The protocol
   described here is intended to provide assurances of integrity and
   time.  A trusted third party is required.

Introduction

   One problem with any system for verifying the integrity of a file is
   that the verifying program itself may be attacked. Thus, although
   users may be reassured by their software that a file has not changed,
   in reality, the file, and the verifier might have both changed.
   Because of this danger, a protocol that does not rely on the
   distribution of some special software, but rather, is based entirely
   on widely used standards, is very useful. It allows users to build
   their own software, or obtain trusted copies of software to do
   integrity checking independently. Therefore, the protocol described
   in this memo is composed of ASCII messages that may be sent using e-
   mail or any other means. There is an existing implementation, Betsi
   [1], that is designed this way. Betsi has been in existence since
   August, 1994, and is operational on the Internet. It can be accessed
   by sending e-mail to  with subject 'help', or via
   the world wide web at http://info.bellcore.com/BETSI/betsi.html.












Rubin                        Informational