April 13, 1995

John Lowry
Senior Member of the Technical Staff

Bolt Beranek and Newman, Inc.
70 Fawcett St
Cambridge, MA.  02138  

email: jlowry@bbn.com

(617) 873-2435 Direct
(617) 873-4086 Fax


Project: Location Independent Information Object Security
(IOS)

Bolt Beranek and Newman, Inc. (BBN), under contract to the
Advanced Research Projects Agency (ARPA), has developed the
Information Object Security (IOS) Tools.  These tools use
object identifiers which are registered as Computer Security
Objects.  ARPA has unlimited rights in the software
containing the objects.  BBN specified, created, and named
the objects under contract to ARPA, and remains the primary
point of contact on all questions regarding naming
conflicts.  The NIST Computer Security Objects Register
(CSOR) assumes no responsibility pertaining to any inquiry
regarding ownership or naming conflicts. 

The IOS software is publicly available and can be obtained
on the Internet for anonymous ftp at ests.bbn.com. 

Object naming information
-------------------------

   IOS Signature Component:  2.16.840.101.3.3.0.3

      iosp (3) components (0) signatureComponent (3)

   id-ios-signatureComponent


Object definition and description
---------------------------------

The signature component is one of several components defined
by the Location Independent Information Object Security
(IOS) project.  The IOS components are used singly or in
combination with others to achieve a variety of security
services.

This is a syntax that denotes an IOS signature component.
The signature component is used to provide digital signature
services and to carry elements necessary for an application
or user to establish non-repudiation.  Multiple signatures
are supported, done sequentially or in parallel.

   SignatureComponent ::= SEQUENCE {
        signedInfo  SEQUENCE {
            dataID                  DataID,
            signedData              ReferenceID,
            certComponentID         [0] DataID OPTIONAL,
            annotationComponentID   [1] DataID OPTIONAL,
            timeStamp               [2] TimeStampData
OPTIONAL,
            signatureAlgorithm      AlgorithmIdentifier
          },
        signature           ENCRYPTED OCTET STRING }


   DataID ::= SEQUENCE {
     componentType   OBJECT IDENTIFIER,
     time            GeneralizedTime,
     random          OCTET STRING SIZE (2..2),
     name            EntityName}

   EntityName ::= SEQUENCE {
     formal          Name OPTIONAL,
     informal        OCTET STRING OPTIONAL}


   TimeStampData ::= SEQUENCE {
     time            GeneralizedTime,
     management      ManagementInfo }

   ManagementInfo ::= SEQUENCE {
     source          TimeSource }
     
   TimeSource ::= PrintableString 


Object usage and rules
-----------------------

Signature components contain a DataID with the object
identifier that defines the type of component.  The DataID
provides a unique identification for a component by the
combination of the componentType, time, random, and name
items.  The random element distinguishes among components
created at the same time by the same user, with the
EntityName.  The informal name field is provided for those
users who do not have Names.  Such users must take care to
supply an informal name that they can be certain is unique,
such as an RFC822 address.

The signature component is constructed so that it can refer
to many components.  The signature value covers the hashes,
of the ASN.1-encoded components listed in the signedData
field plus the hash of the SignedInfo element.

The annotationComponentID is provided as a convenience to
indicate any specific annotation made at the time of
signing.  The annotationComponentID is referenced in the
signedData list if it is covered by the signature.

The TimeStampData associates a time stamp with the component
that contains it.  The time is the actual time of signing,
which may be the same time as in the dataID.  That time,
however, is primarily to ensure uniqueness, whereas the
value of this time is significant as actual time.

ManagementInfo captures information which allows the
recipient to establish trust in the time value.  It may
include the  distinguished name of the server, information
to assure that no post-dating has occurred, Certificate/CRL
information, and a signature.  

The signature value is generated by passing the final hash
value into the appropriate signature function.  This final
hash value is generated by computing a hash value for each
encoded component referenced in the signedData element,
concatenating those in the same order as the elements
appeared in the signedData list, calculating a hash value
for the signedInfo element, appending that to the
concatenation, and then calculating a hash over that entire
string.