Method and system for e-mail message transmission

• US 7,401,356 B2
• Filed: 09/14/2006
• Issued: 07/15/2008
• Est. Priority Date: 07/23/1998
• Status: Expired due to Term

• Current Assignee: Axway Incorporated (Axway Software SA)
• Original Assignee: Tumbleweed Communications Corporation (Axway Software SA)
• Inventors: Bandini, Jean-Christophe Denis, Smith, Jeffrey C.
• Primary Examiner(s): Moise, Emmanuel L
• Assistant Examiner(s): CALLAHAN, PAUL E
• Application Number:
  US11/522,012
• Publication Number:
  US 20070011737A1
• Time in Patent Office: 670 Days
• Field of Search: 726/11, 726/14, 380/259, 713/151, 713/153, 713/154, 713/175, 709/232
• US Class Current: 726/14
• CPC Class Codes: G06Q 10/00 Administration; Management
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 63/02 for separating internal from external traffic, e.g. firewalls
• CPC Class Codes: H04L 63/0227 Filtering policies mail message filtering H04L51/212
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 9/32 including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials

Abstract

An e-mail firewall applies policies to e-mail messages transmitted between a first site and a plurality of second sites. The e-mail firewall includes a plurality of mail transfer relay modules for transferring e-mail messages between the first site and one of the second sites. Policy managers are used to enforce and administer selectable policies. The policies are used to determine security procedures for the transmission and reception of e-mail messages. The e-mail firewall employs signature verification processes to verify signatures in received encrypted e-mail messages. The e-mail firewall is further adapted to employ external servers for verifying signatures. External servers are also used to retrieve data that is employed to encrypt and decrypt e-mail messages received and transmitted by the e-mail firewall, respectively.

Claims

1. A method for signing an e-mail message, the method comprising:

receiving at an e-mail firewall, a plurality of e-mail messages including at least first and second messages from different users associated with different user systems;

with a security manager of the e-mail firewall, determining for each of the received first and second messages if a signature is required by applying a signature policy that references particular attributes of the first and second messages, respectively;

retrieving a signing certificate in accordance with the signature policy for application to at least the first message; and

forwarding both the first and second messages for further processing by the e-mail firewall.

2. The method of claim 1 wherein said determining is by reference to content analysis of an e-mail message for sensitivity classification.

3. The method of claim 1 wherein said application of the signing certificate includes signing by employing a key-based signing scheme which does not include the use of an X.509 certificate.

4. The method of claim 3 wherein said application of the signing certificate includes PGP signing.

5. The method of claim 3 wherein said application of the signing certificate includes RSA signing.

6. The method of claim 1 wherein said retrieving is by reference to attributes of an e-mail message and is facilitated by interaction with an external identity management service.

7. The method of claim 6 wherein said external identity management service is an LDAP service.

8. The method of claim 6 wherein said external identity management service is an ActiveDirectory server.

9. The method of claim 1,

wherein the attributes referenced by the signature policy include one or more of content, destination, source and size of the messages.

10. The method of claim 1, further comprising:

selecting and applying a respective signing certificate to the second message.

11. The method of claim 1, further comprising:

determining, based on the signature policy, that no signing certificate is to be applied to the second message.

12. The method of claim 1, further comprising:

based on a signature selection policy and the referenced attributes, selecting and applying a same signing certificate to both the first and second messages.

13. The method of claim 1, further comprising:

based on a signature selection policy and the referenced attributes, selecting and applying different signing certificates to the first and second messages.

14. A computer program product stored in one or more computer readable media, the program product comprising instruction sequences executable on a computer to:

implement a security manager of a messaging firewall that determines, for individual received messages, if a signature is required and that applies a signature policy that references particular attributes of the individual received messages in the determination;

retrieve a first signing certificate, apply the first signing certificate and thereby sign at least a first one of the received messages based on the signature policy; and

forward both the signed first message and a second one of the received messages for further processing by the messaging firewall.

15. The computer program product of claim 14,

wherein the particular attributes referenced by the signature policy include one or more of content, destination, source and size of the individual received messages.

16. The computer program product of claim 14, wherein the instruction sequences are further executable to:

retrieve a second signing certificate and to apply the second signing certificate to at least the second message based on the signature policy and based on particular attributes of the second message.

17. The computer program product of claim 14, wherein the instruction sequences are further executable to:

apply the first signing certificate to both the first and second messages based on the signature policy and based on particular attributes of the first and second messages.

18. The computer program product of claim 14,

wherein the messages include e-mail messages, and

wherein the messaging firewall is configured to be interposed in SMTP protocol traffic flows.

19. The computer program product of claim 14, further comprising:

an interface to an external identity management service from which the first signing certificate is retrievable.

20. A messaging firewall comprising:

a message relay for receiving a plurality of electronic messages from different users associated with different user systems;

a security manager that determines, for each of the received electronic messages, if inclusion of a signature is required by applying a signature policy that references particular attributes of the received electronic messages;

a signing certificate retrieval interface responsive to the security manager, the signing certificate retrieval interface retrieving signing certificates selected for application to respective ones of the received electronic messages in accordance with the signature inclusion determinations of the policy manager; and

a message transmission interface for transmitting both signed and unsigned ones of the received electronic messages in accordance with the signature inclusion determinations of the policy manager.

21. The messaging firewall of claim 20,

wherein the particular attributes referenced by the signature policy include one or more of content, destination, source and size of the individual received messages.

22. The messaging firewall of claim 20, wherein

the signing certificate retrieval interface retrieves a second signing certificate and the messaging firewall applies the second signing certificate to at least the second message based on the signature policy and based on particular attributes of the second message.

23. The messaging firewall of claim 20,

wherein the first signing certificate is applied by the messaging firewall to both the first and second messages based on the signature policy and based on particular attributes of the first and second messages.

24. The messaging firewall of claim 20,

wherein the messages include e-mail messages, and

wherein the messaging firewall is configured to be interposed in SMTP protocol traffic flows.

25. The messaging firewall of claim 20, further comprising:

an interface to an external identity management service from which at least the first signing certificate is retrievable.

26. A method for verifying a digital signature in a received message, the method comprising:

receiving at a messaging firewall, a plurality of electronic messages including at least first and second messages from different users associated with different user systems;

with a security manager of the messaging firewall, determining for each of the received first and second messages a level of verification required by applying a signature verification policy that references particular attributes of the first and second messages;

attempting to verify the first and second messages to differing levels of confidence in accordance with signature verification policy and the particular attributes of the respective message.