ELECTRONIC DATA COMMUNICATION SYSTEM

• US 20130046986A1
• Filed: 10/23/2012
• Published: 02/21/2013
• Est. Priority Date: 02/02/2006
• Status: Active Grant

• Current Assignee: Trend Micro Inc.
• Original Assignee: Trend Micro Inc.
• Inventors: DANCER, Andrew
• Granted Patent: US 9,667,418 B2
• Time in Patent Office: Days
• US Class Current: 713/171
• 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 51/00 User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail
• CPC Class Codes: H04L 63/045 wherein the sending and receiving network entities apply hybrid encryption, i.e. combination of symmetric and asymmetric encryption cryptographic mechanisms or cryptographic arrangements using a plurality of keys or algorithms H04L9/14
• CPC Class Codes: H04L 63/0471 applying encryption by an intermediary, e.g. receiving clear information at the intermediary and encrypting the received information at the intermediary before forwarding
• CPC Class Codes: H04L 63/126 the source of the received data
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates

Abstract

There is described an electronic data communication system in which encrypted mail messages for a recipient are sent in two parts: message data encrypted by a symmetric encryption algorithm using a session key and session key data encrypted by an asymmetric encryption algorithm using a public key associated with the recipient. If the recipient uses a webmail service to access the encrypted electronic mail message, the encrypted session key data is sent to a trusted third party server which has access to the private key of the user. The trusted third party server decrypts the encrypted session key using the private key of the user, and then sends the decrypted session key to a remote network device for decryption of the encrypted message.

Claims

1. A system for communicating electronic messages to a recipient, the system comprising:

a communications network having a plurality of network devices connected thereto;

a remote network device in the plurality of network devices;

an encryption key server in the plurality of network devices, wherein in response to a request from the remote network device, the encryption key server is operable to encrypt data provided by the remote network device using a cryptographic key associated with the a user of said remote network device and return the resultant encrypted data to the remote network device, the encryption key server being remotely located from the remote network device, and another network device; and

the other network device in the plurality of network devices operable to i) apply a one-way encryption algorithm to a message for communication to the recipient in order to generate a hash value, ii) transmit the hash value to the encryption key server for encryption using the cryptographic key associated with the sender in order to generate a digital signature, and iii) in response to receiving the digital signature from the encryption key server, to append the digital signature to the original message to form a signed message.

2. A network server comprising:

a data store operable to store encrypted electronic messages for a recipient comprising i) encrypted message data corresponding to a message for the recipient encrypted by a symmetric encryption algorithm using a session key and ii) encrypted session key data corresponding to the session key encrypted by an asymmetric encryption algorithm using a public key associated with the recipient;

a network interface operable to receive data from and transmit data to remote network devices; and

a processor operable, following receipt of a request to access an encrypted message, to extract said encrypted session key data from the requested electronic message and forward the extracted encrypted session key data to a remote network device.

3. The network server according to claim 2, wherein the processor is operable to generate link data comprising the encrypted session key data and a network address for an encryption key server.

4. The network server according to claim 3, wherein the processor is operable to generate link data further comprising a redirect network address.

5. The network server according to claim 3, wherein the processor is operable to generate link data further comprising identification data for the recipient.

6. The network server according to claim 3, wherein the processor is operable to generate link data further comprising time data identifying a time period during which the encrypted electronic message was sent.

7. The network server according to claim 3, wherein the link data comprises a uniform resource locater.

8. The network server according to claim 7, wherein the processor is operable to incorporate the generated uniform resource locater in web page data.

9. A method comprising:

recovering a private key associated with a client in a plurality of clients;

decrypting a received encrypted session key data using the recovered private key to recover a session key; and

forwarding the recovered session key to a remote network device.

10. The method according to claim 9, wherein the private key is recovered from a database storing private keys for said plurality of clients.

11. The method according to claim 9 further comprising, generating the private key using a root private key and identification information for the client.

12. The method according to claim 11, wherein the identification information is the electronic mail address for the client.

13. The method according to claim 9, wherein the encrypted session key is received with a network address, and further comprising forwarding the recovered session key to the network address.

14. A method comprising:

recovering a private key associated with a client in a plurality of clients;

encrypting a received hash value using the recovered private key to generate a digital signature; and

forwarding the generated digital signature to a remote network device.

15. The method according to claim 14, wherein the private key is recovered from a database storing the private keys for said plurality of clients.

16. The method according to claim 14, wherein the private key is generated using a root private key and identification information for the client.

17. The method according to claim 16, wherein the identification information is the electronic mail address for the client.