System and method for document-driven processing of digitally-signed electronic documents

• US 20040139327A1
• Filed: 12/24/2003
• Published: 07/15/2004
• Est. Priority Date: 04/13/1999
• Status: Abandoned Application

• Current Assignee: EOAE Services (UK) Ltd. (iSentry Group Ltd.)
• Original Assignee: Ilumin (Broadcom, Inc.)
• Inventors: Israelsen, D. Brent, Brown, Bruce E.
• Application Number:
  US10/746,511
• Publication Number:
  US 20040139327A1
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: G06F 21/34 involving the use of external additional devices, e.g. dongles or smart cards
• CPC Class Codes: G06F 21/602 Providing cryptographic facilities or services
• CPC Class Codes: G06F 21/64 Protecting data integrity, e.g. using checksums, certificates or signatures
• CPC Class Codes: G06F 2221/2149 Restricted operating environment
• CPC Class Codes: G06F 2221/2151 Time stamp
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/605 Copy protection
• CPC Class Codes: H04L 2209/68 Special signature format, e.g. XML format
• CPC Class Codes: H04L 9/3226 using a predetermined code, e.g. password, passphrase or PIN network architectures or network communication protocols for supporting authentication of entities using passwords in a packet data network H04L63/083
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]
• CPC Class Codes: H04L 9/3297 involving time stamps, e.g. generation of time stamps

Abstract

A computer-implemented method for digitally signing an electronic document by a plurality of signers includes determining a signing role of each signer; identifying a to-be-signed portion of the document corresponding to the signing role of each signer; receiving an indication from each signer to digitally sign the document; and applying the digital signature of each signer to the corresponding to-be-signed portion in response to the indication from each signer. A computer-implemented method for processing electronic documents includes receiving a document at a document processing station; reading a processing instruction from a processing portion of the document; identifying a processing service within the document processing station for executing the processing instruction; executing the processing instruction at the document processing station using the identified processing service; and applying a digital signature of the document processing station to the document after the processing instruction is executed.

Claims

1. A computer-implemented method for digitally signing an electronic document by a plurality of signers, each signer having a signing role and a unique private key for applying a digital signature, each signing role corresponding to a to-be-signed portion of the document, at least two signing roles corresponding to different to-be-signed portions, the method comprising:

determining the signing role of each signer;

identifying the to-be-signed portion of the document corresponding to the signing role of each signer;

receiving an indication from each signer to digitally sign the document; and

applying the digital signature of each signer to the corresponding to-be-signed portion in response to the indication from each signer.

2. The method of claim 1, wherein the document is encoded in an extensible markup language (XML) format.

3. The method of claim 1, wherein the determining step comprising:

receiving from a signer a specification of a signing role; and

authenticating the signer for the specified signing role.

4. The method of claim 3, wherein the authenticating step comprises:

receiving a private key from a signer;

encrypting a message using the signer'"'"'s private key;

obtaining a public key of the signer from a public key repository; and

decrypting the message using the signer'"'"'s public key.

5. The method of claim 4, wherein the receiving step comprises:

retrieving the signer'"'"'s private key from a smartcard provided by the signer.

6. The method of claim 5, wherein the authenticating step further comprises:

retrieving previously-acquired biometric data of the signer from the smartcard;

acquiring new biometric data from the signer;

comparing the previously-acquired biometric data with the new biometric data; and

identifying the signer as authentic in response to the previously-acquired biometric data substantially matching the new biometric data.

7. The method of claim 6, wherein the biometric data is selected from the group consisting of fingerprint, iris, facial, and voiceprint data.

8. The method of claim 3, wherein the authenticating step comprises:

receiving a passcode from the signer;

comparing the received passcode with a stored passcode corresponding to the signing role of the signer; and

identifying the signer as authentic in response to the received passcode matching a stored passcode.

9. The method of claim 1, wherein the document comprises at least one delimiter for indicating the to-be-signed portion of the document corresponding to the signing role of a signer, the identifying step comprising:

locating within the document the at least one delimiter corresponding to the signing role of the signer; and

using the at least one delimiter to identify the to-be-signed portion of the document corresponding to the signing role of the signer.

10. The method of claim 9, wherein the delimiter is selected from the group consisting of an extensible markup language (XML) tag and an XML attribute.

11. The method of claim 1, wherein the applying step comprises:

storing within the corresponding to-be-signed portion a date in which the to-be-signed portion is digitally signed by each signer.

12. The method of claim 1, wherein the applying step comprises:

storing within the corresponding to-be-signed portion a time in which the to-be-signed portion is digitally signed by each signer.

13. The method of claim 1, wherein the applying step comprises:

calculating a message digest for the corresponding to-be-signed portion;

encrypting the message digest using the signer'"'"'s private key; and

storing the encrypted message digest in the document as the signer'"'"'s digital signature.

14. The method of claim 13, wherein the applying step further comprises:

storing with the digital signature a corresponding digital certificate, the digital certificate issued by a certificate authority and authenticating the digital signature of the signer.

15. The method of claim 1, further comprising:

prior to the receiving step, displaying to the signer at least the to-be-signed portion of the document.

16. The method of claim 15, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for display to only selected signers, the displaying step comprising:

locating within the document the at least one delimiter;

using the at least one delimiter to identify the access-restricted portion;

determining whether the signer is among the selected signers to whom the access-restricted portion may be displayed; and

displaying the access-restricted portion to the signer when the signer is among the selected signers.

17. The method of claim 1, further comprising:

prior to the receiving step, obtaining from the signer at least one proposed edit to the to-be-signed portion of the document.

18. The method of claim 17, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for editing by only selected signers, the obtaining step comprising:

locating within the document the at least one delimiter;

using the at least one delimiter to identify the access-restricted portion;

determining whether the signer is among the selected signers by whom the access-restricted portion may be edited; and

applying the proposed edit to the access-restricted portion when the signer is among the selected signers.

19. A computer-implemented method for digitally signing an electronic document by a plurality of signers, each signer having a signing role and a unique private key for applying a digital signature, each signing role corresponding to a to-be-signed portion of the document, the document including a signing order for indicating an order in which the document is to be signed by the plurality of signers, the method comprising:

determining a signing role of a signer;

determining whether the signer is signing in the indicated order;

when the signer is signing in the indicated order;

identifying the to-be-signed portion of the document corresponding to the role of the signer;

receiving an indication from the signer to digitally sign the document; and

applying the digital signature of the signer to the corresponding to-be-signed portion.

20. The method of claim 19, wherein the signing order comprises an ordered sequence of signing roles.

21. A computer-implemented method for processing electronic documents, each document comprising a data portion and a processing portion, the processing portion comprising at least one processing instruction, the method comprising:

receiving a document at a document processing station, the document processing station having a unique private key for applying a digital signature to the document;

reading a processing instruction from the processing portion of the document;

identifying a processing service within the document processing station for executing the processing instruction;

executing the processing instruction at the document processing station using the identified processing service; and

applying the digital signature of the document processing station to the document after the processing instruction is executed.

22. The method of claim 21, wherein the document is encoded in an extensible markup language (XML) format.

23. The method of claim 21, wherein the processing instruction is a signing instruction for applying a digital signature of a signer to at least one portion of the document, the signer having a signing role and a unique private key for applying a digital signature, the signing role corresponding to a to-be-signed portion of the document, the executing step comprising:

determining the signing role of the signer;

identifying the to-be-signed portion of the document corresponding to the signing role of the signer;

receiving an indication from the signer to digitally sign the document; and

applying the digital signature of the signer to the corresponding to-be-signed portion in response to the indication of the signer.

24. The method of claim 23, wherein the determining step comprises:

determining the signing role from the signing instruction.

25. The method of claim 23, wherein the determining step comprises:

authenticating the signer for the signing role.

26. The method of claim 25, wherein the authenticating step comprises:

receiving a private key from the signer;

encrypting a message using the private key;

obtaining a public key of the signer from a public key repository; and

decrypting the message using the public key.

27. The method of claim 23, wherein each document processing station is associated with at least one signing role, the determining step comprising:

determining whether the document processing station currently hosting the document is associated with the signing role of the signer; and

in response to the currently-hosting document processing station not being associated with the signing role of the signer;

identifying a document processing station that is associated with the signing role of the signer; and

sending the document to the identified document processing station.

28. The method of claim 23, wherein the document comprises at least one delimiter for indicating the to-be-signed portion of the document corresponding to the signing role of a signer, the identifying step comprising:

locating within the document the at least one delimiter corresponding to the signing role of the signer; and

using the at least one delimiter to identify the to-be-signed portion of the document corresponding to the signing role of the signer.

29. The method of claim 28, wherein the delimiter is selected from the group consisting of an extensible markup language (XML) tag and an XML attribute.

30. The method of claim 23, wherein the executing step further comprises:

prior to the receiving step, displaying to the signer at least the to-be-signed portion of the document.

31. The method of claim 30, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for display to only selected signers, the displaying step comprising:

locating within the document the at least one delimiter;

using the at least one delimiter to identify the access-restricted portion;

determining whether the signer is among the selected signers to whom the access-restricted portion may be displayed; and

displaying the access-restricted portion to the signer when the signer is among the selected signers.

32. The method of claim 23, wherein the executing step further comprises:

prior to the receiving step, obtaining from the signer at least one proposed edit to the to-be-signed portion of the document.

33. The method of claim 32, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for editing by only selected signers, the obtaining step comprising:

locating within the document the at least one delimiter;

using the at least one delimiter to identify the access-restricted portion;

determining whether the signer is among the selected signers by whom the access-restricted portion may be edited; and

applying the proposed edit to the access-restricted portion when the signer is among the selected signers.

34. The method of claim 23, wherein the applying step comprises:

storing within the corresponding to-be-signed portion a date in which the to-be-signed portion is digitally signed by the signer.

35. The method of claim 23, wherein the applying step comprises:

storing within the corresponding to-be-signed portion a time in which the to-be-signed portion is digitally signed by the signer.

36. The method of claim 21, wherein the processing instruction is a document creation instruction for creating at least one new document, the document creation instruction including a specification of a document type for the new document to be created, the executing step comprising:

identifying the document type of the new document from the document creation instruction;

retrieving a document template corresponding to the identified document type;

creating a new document from the document template; and

copying at least a subset of the document into the new document.

37. The method of claim 21, wherein the processing instruction is a notification instruction for sending a notification message to at least one signer, the notification instruction including an indication of the at least one signer, the executing step comprising:

identifying the at least one signer from the notification instruction; and

sending the notification message to the at least one signer.

38. The method of claim 37, wherein the notification message is obtained from the notification instruction.

39. The method of claim 37, wherein the notification message is sent to the signer via e-mail.

40. The method of claim 37, wherein the indication of the at least one signer is selected from the group consisting of an e-mail address of the signer, an indication of the signer'"'"'s role, and an indication of the signer'"'"'s identity.

41. The method of claim 37, wherein the notification instruction includes an indication of a signing time, and wherein the notification message is sent in response to the signer not digitally signing the document before the signing time.

42. The method of claim 37, wherein the notification instruction includes an indication of a reminder time, the executing step further comprising:

determining at the reminder time whether the signer has digitally signed the document; and

in response to the signer not digitally signing the document before the reminder time, sending a reminder message to the signer.

43. The method of claim 21, wherein the processing instruction is a database interaction instruction, the database interaction instruction specifying at least a subset of the document for export to a database, the execution step comprising:

identifying the at least a subset of the document from the database interaction instruction; and

exporting the at least a subset of the document to the database.

44. The method of claim 43, wherein the document is encoded in an extensible markup language (XML) format, the exporting step using at least one open database connectivity (ODBC) call for converting XML document data into a format suitable for the database.

45. The method of claim 21, wherein the processing instruction is a database interaction instruction, the database interaction instruction specifying a query on a database and a portion of the document to receive data imported from the database as a result of the query, the execution step comprising:

identifying from the database interaction instruction the query and the portion of the document to receive the imported data resulting from the query;

executing the query on the database; and

importing the data resulting from the query into the identified portion of the document.

46. The method of claim 45, wherein the document is encoded in an extensible markup language (XML) format, the importing step using at least one open database connectivity (ODBC) call for converting data received as a result of the query into XML document data.

47. The method of claim 21, wherein the processing instruction is a signature verification instruction, the signature verification instruction specifying at least one digital signature to verify within the document, the execution step comprising:

identifying from the signature verification instruction the at least one digital signature to verify within the document;

obtaining from the document a digital certificate corresponding to the digital signature;

using the digital certificate to verify the digital signature.

48. The method of claim 47, wherein the digital certificate and the digital signature each include an indication of the signer'"'"'s identity, wherein the step of using the digital certificate to verify the digital signature comprises:

determining whether the digital certificate has been revoked; and

determining whether digital certificate'"'"'s indication of the signer'"'"'s identity matches the digital signature'"'"'s indication of the signer'"'"'s identity.

49. The method of claim 21, wherein the processing instruction is a payment processing instruction, the payment processing instruction identifying within the document at least one electronic payment request to process, the execution step comprising:

identifying the electronic payment request to process from the payment processing instruction, the electronic payment request including an indication of a payment amount, the electronic payment request being digitally signed by a signer'"'"'s digital signature;

obtaining a digital certificate corresponding to the signer'"'"'s digital signature, the digital certificate indicating a maximum signing authority for the signer;

checking the digital certificate for the signer'"'"'s maximum signing authority; and

completing the electronic payment request when the payment amount does not exceed the signer'"'"'s maximum signing authority.

80. The system claim 21, wherein the processing instruction is a payment processing instruction, the payment processing instruction identifying within the document at least one electronic payment request to process, the electronic payment request including an indication of a payment amount, the electronic payment request being digitally signed by a signer'"'"'s digital signature;

the at least one processing service comprising;

a payment processing service adapted to identify the electronic payment request from the payment processing instruction, obtain a digital certificate indicating a maximum signing authority for the signer and complete the electronic payment request when the payment amount does not exceed the signer'"'"'s maximum signing authority.

50. In a document processing system comprising a plurality of document processing stations, a computer-implemented method for processing electronic documents, each document comprising a data portion and a processing portion, the processing portion comprising at least one processing instruction, each document processing station having a unique private key for applying a digital signature;

the method comprising;

receiving a document at a first document processing station;

reading a processing instruction from the processing portion of the document;

identifying a processing service for executing the processing instruction;

determining whether the identified service is available within the first document processing station;

in response to the identified service not being available within the first document processing station;

locating a second document processing station in which the identified service is available; and

sending the document to the second document processing station;

executing the processing instruction at the second document processing station using the identified processing service; and

applying the digital signature of the second document processing station to the document after the processing instruction is executed.

51. A system for digitally signing an electronic document by a plurality of signers, each signer having a signing role and a unique private key for applying a digital signature, each signing role corresponding to a to-be-signed portion of the document, at least two signing roles corresponding to different to-be-signed portions, the system comprising:

a signing role identifier for identifying the signing role of a signer;

a parser, coupled to the signing role identifier, for parsing the document to identify the to-be-signed portion of the document corresponding to the signing role of the signer; and

a signing module, coupled to the parser, for applying the digital signature of the signer to the corresponding to-be-signed portion in response to receiving an indication to sign from the signer.

52. The system of claim 51, wherein the document is encoded in an extensible markup language (XML) format.

53. The system of claim 51, wherein the signing role identifier is adapted to receive from a signer an indication of a signing role, the system further comprising:

an authenticator, coupled to the signing role identifier, adapted to authenticate the signer for the signing role identified by the signing role identifier.

54. The system of claim 53, further comprising:

a smartcard reader, coupled to the authenticator, adapted to receive the signer'"'"'s private key from a smartcard provided by the signer.

55. The system of claim 54, further comprising:

a biometric data acquisition device, coupled to the authenticator and the smartcard reader, for acquiring new biometric data from the signer to compare with previously-acquired biometric data stored within the smartcard and generate therefrom an authentication signal when the new biometric data substantially matches the previously-acquired biometric data.

56. The system of claim 51, wherein the document comprises at least one delimiter for indicating the to-be-signed portion of the document corresponding to the signing role of the signer, the parser being adapted to locate within the document the at least one delimiter corresponding to the signing role of the signer and use the at least one delimiter to identify the to-be-signed portion of the document corresponding to the signing role of the signer.

57. The system of claim 56, wherein the delimiter is selected from the group consisting of an extensible markup language (XML) tag and an XML attribute.

58. The system of claim 51, further comprising:

a message digest calculator, coupled to the signing module, for calculating a message digest for the to be-signed portion; and

an encryptor, coupled to the message digest calculator, for encrypting the message digest using the signer'"'"'s private key.

59. The system of claim 51, wherein the signing module is adapted to store within the corresponding to-be-signed portion a date and time in which the to-be-signed portion is digitally signed by each signer.

60. The system of claim 51, wherein the signing module is adapted to store with each digital signature a digital certificate, each digital certificate issued by a certificate authority and authenticating each digital signature.

61. The system of claim 51, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for display to only selected signers, the parser being adapted to locate within the document the at least one delimiter and use the at least one delimiter to identify the access-restricted portion, the system comprising:

means, coupled to the parser, for determining whether the signer is among the selected signers to whom the access-restricted portion may be displayed; and

a display device, coupled to the determining means, for displaying the access-restricted portion to the signer when the signer is among the selected signers.

62. The system of claim 51, wherein the document includes at least one delimiter for indicating an access-restricted portion of the document, the access-restricted portion for editing by only selected signers, the parser being adapted to locate within the document the at least one delimiter and use the at least one delimiter to identify the access-restricted portion, the system comprising:

means, coupled to the parser, for determining whether the signer is among the selected signers by whom the access-restricted portion may be edited; and

an input device, coupled to the determining means, for receiving at least one proposed edit to the access-restricted portion when the signer is among the selected signers; and

means, coupled to the input device, for applying the at least one edit to the access-restricted portion when the signer is among the selected signers.

63. A system for digitally signing an electronic document by a plurality of signers, each signer having a signing role and a unique private key for applying a digital signature, each signing role corresponding to a to-be-signed portion of the document, the document including a signing order for indicating an order in which the document is to be signed by the plurality of signers, the system comprising:

a signing role identifier for identifying the signing role of a signer;

a parser, coupled to the signing role identifier, for parsing the document to identify the signing order and to identify the to-be-signed portion of the document corresponding to the signing role of the signer; and

a signing module, coupled to the parser, for applying the digital signature of the signer to the corresponding to-be-signed portion in response to receiving an indication to sign from the signer and in response to the signer signing in the indicated order.

64. The system of claim 63, wherein the signing order comprises an ordered sequence of signing roles.

69. The system of claim 63, wherein the processing instruction is a signing instruction for applying a digital signature of at least one signer to at least one to-be-signed portion of the document, each signer having a signing role and a private key for applying a unique digital signature, each signing role corresponding to at least one to-be-signed portion of the document, the at least one processing service comprising:

a document signing service adapted to determine the signing role of each signer;

identify the to-be-signed portion of the document corresponding to the signing role of each signer, receive an indication from each signer to digitally sign the document, and apply the digital signature of each signer to the corresponding to-be-signed portion in response to the indication from each signer.

70. The system of claim 63, wherein the processing instruction is a document creation instruction for creating at least one new document, the document creation instruction including a specification of a document type for the new document to be created, the at least one processing service comprising:

a document creation service adapted to identify the document type of the new document from the document creation instruction, retrieve a document template corresponding to the identified document type;

create a new document from the document template, and copy at least a subset of the data portion of the document into the data portion of the new document.

71. The system of claim 63, wherein the processing instruction is a notification instruction for sending a notification message to at least one signer, the notification instruction including an indication of the at least one signer, the at least one processing service comprising:

a notification service adapted identify the at least one signer from the notification instruction and send the notification message to the at least one signer.

72. The system of claim 71, wherein the notification message is sent via e-mail.

73. The system of claim 71, wherein the notification instruction includes an indication of a signing time, and wherein the notification service is adapted to send the notification message in response to the signer not digitally signing the document before the signing time.

74. The system of claim 63, wherein the processing instruction is a database interaction instruction, the database interaction instruction specifying at least a subset of the document for export to a database, the at least one processing service comprising:

a database interaction service adapted to identify the at least a subset of the document from the database interaction instruction and export the at least a subset of the document to the database.

75. The system of claim 74, wherein the document is encoded in an extensible markup language (XML) format, and the database interaction service uses at least one open database connectivity (ODBC) call for converting XML document data into a format suitable for the database.

76. The system of claim 63, wherein the processing instruction is a database interaction instruction, the database interaction instruction specifying a query on a database and a portion of the document to receive data imported from the database as a result of the query, the at least one processing service comprising:

a database interaction service adapted to identify from the database interaction instruction the query and the portion of the document to receive the imported data resulting from the query, execute the query on the database, and import the data resulting from the query into the identified portion of the document.

77. The system of claim 76, wherein the document is encoded in an extensible markup language (XML) format, and database interaction service uses at least one open database connectivity (ODBC) call for converting data received as a result of the query into XML document data.

78. The system of claim 63, wherein the processing instruction is a signature verification instruction, the signature verification instruction specifying at least one digital signature to verify within the document, the at least one processing service comprising:

an signature verification service adapted to identify from the signature verification instruction the at least one digital signature to verify within the document, obtain from the document a digital certificate corresponding the digital signature, and use the digital certificate to verify the digital signature.

79. The system of claim 78, wherein the digital certificate and the digital signature each include an indication of the signer'"'"'s identity, wherein signature verification service is adapted to determine whether the digital certificate has been revoked and determine whether digital certificate'"'"'s indication of the signer'"'"'s identity matches the digital signature'"'"'s indication of the signer'"'"'s identity.

65. A system for processing electronic documents, the system comprising:

at least one document processing station, each document processing station comprising;

a computer-readable medium for storing an electronic document, the document comprising a data portion and a processing portion, the processing portion comprising at least one processing instruction;

a parser, coupled to the computer-readable medium, for reading a processing instruction from the processing portion of the document and identifying a processing service for executing the processing instruction;

at least one processing service, coupled to the parser, for executing the processing instruction; and

an signing module, coupled to the processing service, for applying the digital signature of the document processing station to the document after the processing instruction is executed.

66. The system of claim 65, wherein a first document processing station stores the document to be processed, the document comprising a first processing instruction for which a corresponding processing service is not available within the first document processing station, the system comprising:

means within the first document processing station for determining that the corresponding processing service is not available;

means, coupled to the determining means, for locating a second document processing station in which the corresponding processing service is available; and

a network, coupled to the first and second document processing stations and to the locating means, for sending the document from the first document processing station to the second document processing station in response to the locating means.

67. The system of claim 66, wherein the determining means is a parser.

68. The system of claim 67, wherein the locating means is a processing service name server, the processing service name server adapted to associate names of processing services with document processing stations in which corresponding processing services are available.

81. A computer-readable medium having computer-readable code embodied therein for digitally signing an electronic document by a plurality of signers, each signer having a signing role and a unique private key for applying a digital signature, each signing role corresponding to a to-be-signed portion of the document, at least two signing roles corresponding to different to-be-signed portions, the computer-readable medium comprising:

computer-readable code adapted for determining the signing role of each signer;

computer-readable code adapted for identifying the to-be-signed portion of the document corresponding to the signing role of each signer;

computer-readable code adapted for receiving an indication from each signer to digitally sign the document; and

computer-readable code adapted for applying the digital signature of each signer to the corresponding to-be-signed portion in response to the indication from each signer.

82. A computer-readable medium having computer-readable code embodied therein for processing electronic documents, each document comprising a data portion and a processing portion, the processing portion comprising at least one processing instruction, the computer-readable medium comprising:

computer-readable code adapted for receiving a document at a document processing station, the document processing station having a unique private key for applying a digital signature to the document;

computer-readable code adapted for reading a processing instruction from the processing portion of the document;

computer-readable code adapted for identifying a processing service within the document processing station for executing the processing instruction;

computer-readable code adapted for executing the processing instruction at the document processing station using the identified processing service; and

computer-readable code adapted for applying the digital signature of the document processing station to the document after the processing instruction is executed.