Signature data object

• US 5,367,573 A
• Filed: 07/02/1993
• Issued: 11/22/1994
• Est. Priority Date: 07/02/1993
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Quimby, John
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US08/086,946
• Time in Patent Office: 508 Days
• Field of Search: 380/3, 380/4, 380/23, 380/25, 380/30
• US Class Current: 713/167
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A "signature data object" (SDO) is a machine-readable structured data record which a signer may associate with a parent object, e.g., an electronic document. An SDO comprises three required encoded parts: A signature header structure; a signature data structure; and a signature proof block. An SDO may include data identifying a role in which the signer is acting and a message code encoding a semantic for the parent object/document such as "submitted by," "approved," etc. In one embodiment, the SDO includes at least one descriptor of (1) a subordinate part of the parent object or (2) an attachment of the parent object/document, to whose (i) value or (ii) presence the validity of the signature data object is bound. An SDO may also include data indicating that it supersedes a specified other SDO associated with that parent object.

Claims

1. A machine-readable data structure being a signature data object created by a machine-executed process encoding data representing a signal generated by a signer, said signature data object comprising:

(a) a signature header structure describing said signal and its meaning comprising (1) a signature unique identifier code, (2) a code representing a date and time, (3) an application process identification code identifying a process which created said signature data object, (4)a signer identification code, and (5) a message code imparting a semantic value to the signal generated by the signer;

(b) a parent object identification code identifying a parent object associated with said signature data object; and

(c) a signature proof structure describing security and validation methods used in constructing said signature data object and data associated with proving the authenticity and validity of said signal.

2. The signature data object of claim 1, wherein said signer identification code encodes user profile data specific to the signer.

3. The signature data object of claim 1, wherein said signer identification code encodes a text string representing a role played by said signer.

4. The signature data object of claim 1, wherein said application process identification code includes an encoded version number of said process which created said signature data object.

5. The signature data object of claim 1, wherein the data encoded in said signature header structure further comprises at least one of the following:

(a) a principal identifier of an associated end user on whose behalf the signature is generated;

(b) an identifier of a security domain from which said signature data object was created; and

(c) a signature unique identifier of another signature data object having the same parent object that is superseded by said signature data object.

6. The signature data object of claim 1, wherein the data encoded in said parent object identification code further comprises a descriptor for each part of the parent object and a value expression specification associated with each descriptor.

7. The signature data object of claim 6, wherein said parent object is an expense authorization form, wherein said descriptor represents a total monetary value field of a purchase order, and said value expression specification specifies that the total monetary value field is less than a specified amount.

8. The signature data object of claim 1, wherein the data encoded in said parent object identification code further comprises at least one descriptor representing (1) a subordinate part of the parent object or (2) an attachment of the parent object to whose value said signature data object is bound.

9. The signature data object of claim 8, wherein said signature data object represents a signature authorizing expenditures, said parent object is an expense authorization form, and one of said descriptors represents a total monetary value field of a purchase order.

10. The signature data object of claim 1, wherein the data encoded in said parent object identification code further comprises at least one descriptor representing (1) a subordinate part of the parent object or (2) an attachment of the parent object to whose presence said signature data object is bound.

11. The signature data object of claim 10, wherein said signature data object represents a signature of approval, said parent object is an expense voucher, and one of said descriptors represents an attachment which is an expense justification memo.

12. The signature data object of claim 1, wherein the data encoded in said parent object identification code further comprises at least one descriptor of a second signature data object associated with said parent object, wherein the validity of said signature data object is bound to the presence and validity of said second signature data object.

13. A method of transmitting to a receiver an electronic document with a signature of a signer comprising the steps of:

(a) creating a signature data object in accordance with claim 1;

(b) associating said signature data object with the electronic document; and

(c) transmitting the electronic document and said signature object to the receiver.

14. The signature data object of claim 1, wherein said semantic value imparted to the message code comprises one of an approval, a disapproval, or an abstention.

15. A machine-readable data structure being a signature data object created by a machine-executed process encoding data representing a signal generated by a signer, said signature data object comprising:

(a) a signature unique identifier code;

(b) a code representing a date and time;

(c) an application process identification code identifying the process which created said signature data object;

(d) a signer identification code;

(e) a message code imparting a semantic value to said signal;

(f) a parent object identification code identifying a parent object associated with said signature data object;

(g) at least one descriptor representing (1) a subordinate part of said parent object to whose value or presence said signature data object is bound; and

(h) a signature proof structure describing security and validation methods used in constructing said first signature data object, and data associated with proving the validity of said signal.

16. The signature data object of claim 15, wherein said signer identification code includes a text string encoding a role played by said signer.

17. A machine-readable program storage device encoding a program comprising machine-executable instructions which, when executed on a computer system, result in creating said signature data object as specified in claim 15.