Anonymizing emails between sender and recipient

• US 9,118,632 B1
• Filed: 03/12/2015
• Issued: 08/25/2015
• Est. Priority Date: 03/12/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Lidzborski, Nicolas, Chuang, Weihaw
• Primary Examiner(s): Traore, Fatoumata
• Application Number:
  US14/656,039
• Time in Patent Office: 166 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 2209/76 Proxy, i.e. using intermediary entity to perform cryptographic operations
• CPC Class Codes: H04L 51/48 Message addressing, e.g. address format or anonymous messages, aliases
• CPC Class Codes: H04L 63/0414 during transmission, i.e. party's identity is protected against eavesdropping, e.g. by using temporary identifiers, but is known to the other party or parties involved in the communication
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates

Abstract

A sender may generate a primary email including a primary header and a primary body, the primary header including a sender address associated with the sender computing system and the recipient address associated with a recipient client, encrypt at least a part of the primary body to generate a primary encrypted email, encrypt the primary encrypted email to generate an encrypted sender-to-recipient pseudo-body, add a trusted party-to-recipient header to the encrypted sender-to-recipient pseudo-body including a trusted party address of a trusted party and the recipient address associated with the recipient client to generate a trusted party-to-recipient email, encrypt the trusted party-to-recipient email to generate an encrypted trusted party-to-recipient pseudo-body, add a sender-to-trusted party header to the encrypted trusted party-to-recipient pseudo-body including the sender address and the address of the trusted party to generate a sender-to-trusted party email, and send the sender-to-trusted party email to the trusted party.

Claims

1. A non-transitory computer-readable storage medium comprising instructions stored thereon for protecting a recipient address within a primary email that, when executed by at least one processor, are configured to cause a sender computing system to at least:

generate the primary email, the primary email including a primary header and a primary body, the primary header including a sender address associated with the sender computing system and the recipient address associated with a recipient client;

encrypt at least a part of the primary body to generate a primary encrypted email;

encrypt the primary encrypted email to generate an encrypted sender-to-recipient pseudo-body;

add a trusted party-to-recipient header to the encrypted sender-to-recipient pseudo-body, the trusted party-to-recipient header including a trusted party address of a trusted party and the recipient address associated with the recipient client, to generate a trusted party-to-recipient email;

encrypt the trusted party-to-recipient email according to a symmetric key to generate an encrypted trusted party-to-recipient pseudo-body;

generate a sender-to trusted party email by;

adding a sender-to-trusted party header to the encrypted trusted party-to-recipient pseudo-body, the sender-to-trusted party header including the sender address and the address of the trusted party; and

adding a sender-to-trusted party trailer to the encrypted trusted party-to-recipient pseudo-body, the sender-to-trusted party trailer including the symmetric key, the symmetric key being encrypted according to a public key associated with the trusted party; and

send the sender-to-trusted party email to the trusted party.

2. The non-transitory computer-readable storage medium of claim 1, wherein the encrypting the primary encrypted email includes encrypting the primary encrypted email according to the symmetric key included in the trusted party-to-recipient trailer to generate the encrypted sender-to-recipient pseudo-body.

3. The non-transitory computer-readable storage medium of claim 1, wherein the instructions are further configured to cause the sender computing system to:

add a trusted party-to-recipient trailer to the encrypted sender-to-recipient pseudo-body, the trusted party-to-recipient trailer including a recipient symmetric key, the recipient symmetric key being encrypted according to a public key associated with the recipient client, the adding the trusted party-to-recipient header and the adding the trusted party-to-recipient trailer to the encrypted sender-to-recipient pseudo-body generating the trusted party-to-recipient email,

wherein the encrypting the primary encrypted email includes encrypting the primary encrypted email according to the recipient symmetric key included in the trusted party-to-recipient trailer to generate the encrypted sender-to-recipient pseudo-body.

4. The non-transitory computer-readable storage medium of claim 3, wherein the public key associated with the recipient client is included in a public key infrastructure (PKI) certificate associated with the recipient client and the public key associated with the trusted party is included in a PKI certificate associated with the trusted party.

5. The non-transitory computer-readable storage medium of claim 4, wherein the PKI certificate associated with the trusted party is included in a chain of certificates from a PKI certificate associated with the sender computing system and a trusted root.

6. The non-transitory computer-readable storage medium of claim 1, wherein the primary email includes an X.509 certificate.

7. The non-transitory computer-readable storage medium of claim 6, wherein the X.509 certificate includes an extension declaring that a public key included in the X.509 certificate will be used to proxy the primary email via the trusted party.

8. The non-transitory computer-readable storage medium of claim 6, wherein the X.509 certificate includes an extension specifying the address of the trusted party and indicating that the trusted party will decrypt the encrypted trusted party-to-recipient pseudo-body and forward the trusted party-to-recipient email to the recipient client.

9. The non-transitory computer-readable storage medium of claim 6, wherein the X.509 certificate includes:

a first extension declaring that a public key included in the X.509 certificate will be used to proxy the primary email via the trusted party; and

a second extension specifying the address of the trusted party and indicating that the trusted party will decrypt the encrypted trusted party-to-recipient pseudo-body and forward the trusted party-to-recipient email to the recipient client.

10. The non-transitory computer-readable storage medium of claim 6, wherein the X.509 certificate includes a certificate signature, the certificate signature authenticating the X.509 certificate and being based on a private key of an entity that issued the certificate.

11. The non-transitory computer-readable storage medium of claim 1, wherein the primary encrypted email further includes a trailer, the trailer including a primary encrypted email signature, the primary encrypted email signature authenticating the sender computing system and being based on a private key associated with the sender computing system.

12. A non-transitory computer-readable storage medium comprising instructions stored thereon for forwarding a sender-to-trusted party email to a trusted party server associated with a recipient client that, when executed by a least one processor, are configured to cause a trusted party computing system associated with a sender client to at least:

receive, from the sender client, a sender-to-trusted party email, the sender-to-trusted party email including;

a sender-to-trusted party header including a sender address associated with the sender client and a first trusted party address associated with the trusted party computing system;

an encrypted trusted party-to-trusted party pseudo-body; and

a sender-to-trusted party trailer, the sender-to-trusted party trailer including a key for decrypting the encrypted trusted party-to-trusted party pseudo-body, the key being encrypted according to a public key associated with the trusted party computing system;

remove the sender-to-trusted party header from the sender-to-trusted party email;

decrypt the encrypted trusted party-to-trusted party pseudo-body to generate a trusted party-to-trusted party email, the trusted party-to-trusted party email including a trusted party-to-trusted party header and an encrypted trusted party-to-recipient pseudo-body, the trusted party-to-trusted party header including the first trusted party address and a second trusted party address associated with the trusted party server associated with the recipient client; and

send the trusted party-to-trusted party email to the trusted party server associated with the recipient client.

13. The non-transitory computer-readable storage medium of claim 12, wherein the decrypting the encrypted trusted party-to-trusted party pseudo-body includes:

decrypting the key included in the sender-to-trusted party trailer according to a private key associated with the trusted party computing system; and

decrypting the encrypted trusted party-to-trusted party pseudo-body with the decrypted key.

14. A non-transitory computer-readable storage medium comprising instructions stored thereon for forwarding a sender-to-trusted party email to a recipient client that, when executed by a least one processor, are configured to cause a trusted party computing system to at least:

receive, from a sender client, a sender-to-trusted party email, the sender-to-trusted party email including;

a sender-to-trusted party header including a sender address associated with the sender client and a trusted party address associated with the trusted party computing system;

an encrypted trusted party-to-recipient pseudo-body; and

a sender-to-trusted party trailer, the sender-to-trusted party trailer including a key for decrypting the encrypted trusted party-to-recipient pseudo-body;

remove the sender-to-trusted party header from the sender-to-trusted party email;

decrypt the encrypted trusted party-to-recipient pseudo-body to generate a trusted party-to-recipient email, the trusted party-to-recipient email including a trusted party-to-recipient header and an encrypted sender-to-recipient pseudo-body, the trusted party-to-recipient header including the trusted party address associated with the trusted party computing system and a recipient address associated with the recipient client, the encrypted sender-to-recipient pseudo-body including an encrypted email from the sender client to the recipient client; and

send the trusted party-to-recipient email to the recipient client.

15. The non-transitory computer-readable storage medium of claim 14, wherein the trusted party computing system is associated with the sender client.

16. The non-transitory computer-readable storage medium of claim 14, wherein the trusted party computing system is associated with the recipient client.

17. The non-transitory computer-readable storage medium of claim 14, wherein the key included in the sender-to-trusted party trailer is encrypted according to a public key associated with the trusted party computing system.

18. The non-transitory computer-readable storage medium of claim 17, wherein the decrypting the encrypted trusted party-to-recipient pseudo-body includes:

decrypting the key included in the sender-to-trusted party trailer according to a private key associated with the trusted party computing system; and

decrypting the encrypted trusted party-to-recipient pseudo-body with the decrypted key.

19. The non-transitory computer-readable storage medium of claim 14, wherein the decrypting the encrypted trusted party-to-recipient pseudo-body includes decrypting the encrypted trusted party-to-recipient pseudo-body based on the key included in the sender-to-trusted party trailer.

20. A method for forwarding a sender-to-trusted party email to a trusted party server associated with a recipient client, the method being performed by a trusted party computing system associated with a sender client, the method comprising:

receive, from the sender client, a sender-to-trusted party email, the sender-to-trusted party email including;

a sender-to-trusted party header including a sender address associated with the sender client and a first trusted party address associated with the trusted party computing system;

an encrypted trusted party-to-trusted party pseudo-body; and

a sender-to-trusted party trailer, the sender-to-trusted party trailer including a key for decrypting the encrypted trusted party-to-trusted party pseudo-body, the key being encrypted according to a public key associated with the trusted party computing system;

remove the sender-to-trusted party header from the sender-to-trusted party email;

decrypt the encrypted trusted party-to-trusted party pseudo-body to generate a trusted party-to-trusted party email, the trusted party-to-trusted party email including a trusted party-to-trusted party header and an encrypted trusted party-to-recipient pseudo-body, the trusted party-to-trusted party header including the first trusted party address and a second trusted party address associated with the trusted party server associated with the recipient client; and

send the trusted party-to-trusted party email to the trusted party server associated with the recipient client.

21. The method of claim 20, wherein the decrypting the encrypted trusted party-to-trusted party pseudo-body includes:

decrypting the key included in the sender-to-trusted party trailer according to a private key associated with the trusted party computing system; and

decrypting the encrypted trusted party-to-trusted party pseudo-body with the decrypted key.