E-mail firewall with stored key encryption/decryption

• US 20070005983A1
• Filed: 09/05/2006
• Published: 01/04/2007
• Est. Priority Date: 07/24/1997
• Status: Active Grant

• Current Assignee: Axway Incorporated (Axway Software SA)
• Original Assignee: Axway Incorporated (Axway Software SA)
• Inventors: Krishnamurthy, Sathvik, Dickinson, Robert
• Granted Patent: US 8,255,683 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/76 Proxy, i.e. using intermediary entity to perform cryptographic operations network architectures or network communication protocols using hop-by-hop encryption H04L63/0464
• CPC Class Codes: H04L 51/063 Content adaptation, e.g. replacement of unsuitable content
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 51/224 providing notification on incoming messages, e.g. pushed notifications of received messages
• CPC Class Codes: H04L 63/0227 Filtering policies mail message filtering H04L51/212
• CPC Class Codes: H04L 63/0245 Filtering by information in the payload
• CPC Class Codes: H04L 63/0263 Rule management
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0464 using hop-by-hop encryption, i.e. wherein an intermediate entity decrypts the information and re-encrypts it before forwarding it

Abstract

An e-mail firewall (105) applies policies to e-mail messages (204) between a first 5 site and a plurality of second sites in accordance with a plurality of administrator selectable policies (216). The firewall comprises a simple mail transfer protocol (SMTP) relay (202) for causing the e-mail messages (204) to be transmitted between the first site and selected ones of the second sites. A plurality of policy managers (216) enforce-administrator selectable policies. The policies, such as encryption and decryption policies, comprise at least a first source/destination policy (218), at least a first content policy (202) and at least a first virus policy (224). The policies are characterized by a plurality of administrator selectable criteria (310), a plurality of administrator selectable exceptions (312) to the criteria and a plurality of administrator selectable actions (314, 316, 322) associated with the criteria and exceptions. The policy managers comprise an access manager (218) for restricting transmission of e-mail messages (204) between the first site and the second sites in accordance with the source/destination policy (218). The policy managers (216) further comprise a content manager (220) for restricting transmission of e-mail messages (204) between the first site and the second sites in accordance with the content policy (220), and a virus manager (224) for restriction transmission of e-mail messages (204) between the first site and the second sites in accordance with the virus policy (224).

Claims

1. A method for filtering e-mail messages transmitted from an external site to an internal site associated with a first policy, comprising:

i. intercepting an e-mail message having a sender address associated with an external site;

ii. detecting whether the message includes a digital signature;

iii. applying at least one policy condition to said e-mail message, said policy condition applied by reference to said digital signature, said applying providing a policy application result;

iv. applying at least a second policy condition to said e-mail message in response to a predetermined condition of the digital signature, the second policy condition selected by reference to an identity associated with the valid digital signature;

v. detecting that the digital signature is a valid digital signature; and

vi. processing said e-mail message in accordance with said applying of the second policy.

2. A method for filtering e-mail messages transmitted from an external site to an internal site associated with a first policy, comprising:

i. intercepting an e-mail message having a sender address associated with an external site;

ii. detecting whether the message includes a digital signature;

iii. applying at least one policy condition to said e-mail message, said policy condition applied by reference to said digital signature, said applying providing a policy application result;

iv. applying a second policy for detecting whether the signature is associated with a domain which is included in a stored list of trusted domains; and

vi. processing said application level e-mail message in accordance with said applying of the second policy.