CONFIDENTIAL MAIL WITH TRACKING AND AUTHENTICATION

• US 20090006851A1
• Filed: 06/29/2007
• Published: 01/01/2009
• Est. Priority Date: 06/29/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Kay, Jeffrey B., Freeman, Trevor W., Souza, Jeremy De, Mehta, Mayank
• Granted Patent: US 9,847,977 B2
• Time in Patent Office: Days
• US Class Current: 713/170
• 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 63/126 the source of the received data
• CPC Class Codes: H04L 63/166 at the transport layer

Abstract

A method for confidential electronic communication between a sender workstation and a receiver workstation is provided, whereby privacy is guaranteed for the electronic communications transmitted over the public Internet. The method of confidential communication is equipped with message tracking and message receipt verification. The system for implementing the method includes a sender server that creates a session content encryption key along with a message envelope that includes a content encryption key encrypted message and a confidential mail token. The content encryption key is stored securely inside the sender organization'"'"'s system which transmits the message envelope to an intended recipient. The intended recipient processes the message envelope in order to generate a message receipt verification, which is transmitted to the sender. The message receipt verification is processed by the sender server to verify that the message envelope reached the intended recipient. The message receipt verification, which is comprised of the confidential mail token and unique verification data generated by the intended recipient allows the sender server to verify that the message envelope reached the intended receiver and that the message envelope identified as received is authentic. Following verification that the message transmitted by the sender reached the intended receiver and is authorized, the sender transmits the content encryption key to the intended receiver.

Claims

1. A method of verifying that an electronic communication has been received by an intended recipient comprising:

(a) creating an message envelope including at least an encrypted message and a confidential mail token;

(b) transmitting the message envelope from a sender to an intended recipient;

(c) processing of at least a portion of the data within the message envelope by the intended recipient, resulting in generating a verification return receipt;

(d) transmitting the verification return receipt from the intended recipient to the sender; and

(e) processing of the verification return receipt by the sender to verify that the message envelope reached the intended recipient.

2. The method of claim 1 wherein the confidential mail token is comprised of a plurality of data fields, wherein a first data field within said plurality of data fields is comprised of data representative of a content encryption key encrypted with a public key of the sender, wherein a second data field within said plurality of data fields is comprised of data representative of a hash of a combination of data representative of the encrypted message encrypted with the content encryption key and data representative of a hash of a message signed with a private key of the sender, wherein a third data field within said plurality of data fields is comprised of data representative of a content encryption key encryption of data representative of the hash of an encrypted message encrypted with the content encryption key.

3. The method of claim 1 wherein the confidential mail token is comprised of a plurality of data fields, wherein a data field within the plurality of data fields includes a privacy policy bit having a first setting which dictates that an encrypted message may be decrypted by an organization server of the intended receiver and forwarded to the intended receiver.

4. The method of claim 1 wherein the confidential mail token is comprised of a plurality of data fields, wherein a data field within the plurality of data fields includes a privacy policy bit having a second setting which dictates that an encrypted message may only be decrypted by the intended receiver through use of a certificate verifying the intended receiver'"'"'s identity

5. The method of claim 1 wherein the confidential mail token is comprised of a plurality of data fields, wherein a data field within the plurality of data fields includes an encrypted time stamp that facilitates tracking of timing associated with receipt of the transmitted message envelope.

6. The method of claim 1 further comprising, creating a session content encryption key for each message session initiated and transmitting the session content encryption key to the intended recipient following verification that the message envelope reached the intended recipient.

7. The method of claim 1 wherein the verification receipt comprises a confidential mail token, data representative of an email address of the intended recipient, and a unique data set generated by the intended recipient, wherein the unique data set is derived from data within the message envelope.

8. The method of claim 1 further comprising, verifying that the electronic communication was received by the intended receiver through processing of data representative of an email address of the intended recipient and a unique data set generated by the intended recipient.

9. The method of claim 1 further comprising:

(a) creating a session content encryption key for each message session initiated;

(b) the message envelope further comprising at least data representative of;

(i) an encrypted version of the electronic communication, encrypted through use of a content encryption key; and

(ii) a hashed version of the electronic communication signed with a private key of a sender;

(c) wherein the confidential mail token is comprised of a plurality of data fields including at least data representative of;

(1) an encryption of the content encryption key;

(2) a hash of a data combination comprising the encrypted version of the electronic communication and the hashed version of the electronic communication signed with a private key of a sender; and

(3) an encryption of data representative of a hash of the encrypted version of the electronic communication, wherein the encryption is performed through the use of the content encryption key.

10. The method of claim 9 wherein the encryption of the content encryption key is performed by use of a sender'"'"'s private key.

11. The method of claim 8 wherein verifying that the electronic communication was received by the intended receiver further includes:

(a) decrypting the encryption of the content encryption key and using the content encryption key to decrypt the encryption of data representative of a hash of the encrypted version of the electronic communication; and

(b) comparing the decrypted data representative of a hash of the encrypted version of the electronic communication to a hash of the encrypted version of the communication generated by the intended recipient.

12. The method of claim 3 wherein the confidential mail token further includes an encrypted email address of message the intended message recipient which is used in combination with the privacy policy bit to control message authentication.

13. The method of claim 8 wherein the message envelope further comprises data representative of:

(a) a signed hash of the confidential mail token, signed with a sender'"'"'s private key; and

(b) a certificate representative of the sender domain.

14. The method of claim 8 wherein the sender verifies that the electronic communication was received by the intended receiver by:

(a) processing the confidential mail token transmitted from the intended receiver in order to determine the content encryption key;

(b) utilizing the content encryption key to decrypt the hash of the encrypted version of the electronic communication within the confidential mail token; and

(c) comparing the decrypted hash of the encrypted version of the electronic communication within the confidential mail token with the hash of the encrypted version of the communication transmitted by the intended receiver.

15. A system for authenticating confidential email communications transmitted from a sender to a receiver, the system comprising:

(a) a sender server configured to create and transmit an electronic message envelope including at least an encrypted message and a confidential mail token;

(b) a client server configured to process data within the electronic message envelope received and generate a secret identifier that can only be generated if the client server is in possession of the message envelope, the client server being further configured to transmit the secret identifier to the sender server following generation of the secret identifier;

wherein the sender server processes the secret identifier transmitted by the client server to verify that the message envelope reached its intended receiver.

16. The system of claim 15 wherein the sender server transmits a first encryption key to the client server following verification that the message envelope reached the intended receiver.

17. The system of claim 15 wherein the secret identifier comprises a hash of the encrypted message generated by the intended recipient.

20. The computer-readable medium of claim 17 wherein the verification receipt includes a unique data set generated by the intended receiver which is processed to verify that the message is authentic.

18. A computer-readable medium which stores a set of instructions which when executed performs a method for providing confidential electronic communication with tracking and authentication, the method executed by the set of instructions comprising:

(a) creating an message envelope including at least an encrypted message and a confidential mail token;

(b) transmitting the message envelope from a sender to an intended receiver,

(c) processing of data extracted from the message envelope by the intended receiver and generating a verification return receipt; and

(d) transmitting the verification return receipt from the intended receiver to the sender; and

(d) processing of the verification return receipt by the sender to verify that the message envelope reached the intended receiver.

19. The computer-readable medium of claim 18 wherein the method executed by the set of instructions further comprises transmitting a first encryption key to the intended receiver following verification that the message envelope reached the intended receiver and decrypting an first encryption key encrypted time stamp within the verification return receipt.