US Patent 8,898,238 — Active e-mail filter with challenge-response

Life of the patent

28 dated events

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Abstract

When a user receives potential junk e-mail from an unknown sender address, an active filter installed in or cooperating with the user\'s e-mail system sends a challenge e-mail back to the sender address. Unless the user receives a correct response e-mail from the sender address and/or a response that meets formal criteria, the active filter rejects the original e-mail and blocks future e-mail from that sender address. The challenge preferably includes a question that the sender must correctly answer in his response. The question is such that only humans can interpret and respond to it correctly. For example, the question may relate to and/or be incorporated in an image in the challenge. Lists of approved and blocked sender addresses are compiled. The user may directly enter addresses in the address lists. Addresses to which the user has sent e-mail may also be included directly in the approved list.

Claims

42 · 3 independent · depth 5

42 granted claims

›1.independentA method for filtering electronic mail (e-mail) sent to a user e-mail system comprising:nreceiving at the user e-mail system a current e-mail message …+35

A method for filtering electronic mail (e-mail) sent to a user e-mail system comprising:nreceiving at the user e-mail system a current e-mail message sent from a sender address, wherein the e-mail system has a plurality of different levels of security ranging from high to low, each level of security associated with a different set of one or more e-mail filters;determining that a current level of security has been selected by the user, wherein the current level of security as selected by the user is associated with a challenge-response filter;determining that the current e-mail message is not a challenge e-mail response message sent from the sender address in response to a previous challenge rendered by the user e-mail system, the previous challenge having been identified at a computing device associated with the sender address by a valid challenge key in the previous challenge rendered by the user e-mail system, the valid challenge key identifying a message as a challenge requiring a challenge e-mail response message;returning to the sender address a challenge that requires a correct challenge response, wherein the challenge rendered by the user's e-mail system is selected from a plurality of challenges generated by an external provider of challenges, the challenge being sent to the sender address via e-mail;storing the current e-mail message sent from the sender address in an intermediate buffer coupled to the user e-mail system;receiving a challenge e-mail response message sent from the sender address in response to the challenge rendered by the user's e-mail system; andevaluating the challenge e-mail response message to determine whether the challenge response message includes a correct challenge response and corresponds to a formal criterion, wherein the formal criterion is a server of the sender being configured to accept e-mail, wherein future e-mail messages from senders associated with servers that do not accept e-mail are prevented from reaching an intended recipient at the user e-mail system.

›2.↳ 1The method of claim 1, further comprising blocking all future e-mail messages from the sender address until a challenge e-mail response message includ…d2

›3.↳ 1The method of claim 1, wherein the challenge rendered by the user e-mail system includes an instruction to the recipient at the sender address to perf…d2+22

›4.↳ 3The method of claim 3, wherein the action to be performed includes a response to a question.d3+5

›5.↳ 4The method of claim 4, wherein the challenge rendered by the user e-mail system is accompanied by an image.d4+4

›6.↳ 5The method of claim 5, wherein the performed action includes a response to a question concerning the image, the response including selection of an obj…d5

›7.↳ 5The method of claim 5, wherein the performed action includes a response to a question concerning the image, the response including the manual entry of…d5

›8.↳ 5The method of claim 5, wherein the challenge rendered by the user e-mail system is further accompanied by an audio file that instructs the recipient a…d5

›9.↳ 5The method of claim 5, wherein the challenge rendered by the user e-mail system is further accompanied by an audio file that instructs the recipient a…d5

›10.↳ 3The method of claim 3, wherein a user of the user e-mail system selects a challenge generated by the external provider of challenges.d3

›11.↳ 3The method of claim 3, wherein the action must be correctly performed within a predefined response period.d3

›12.↳ 3The method of claim 3, wherein multiple attempts are allowed to correctly perform the action.d3+2

›15.↳ 3The method of claim 3, further comprising:nadding the sender address to a list of approved sender addresses upon receipt of a challenge e-mail respons…d3+6

›16.↳ 15The method of claim 15, wherein adding the sender to a list of approved sender addresses includes manually adding user-specified e-mail addresses to t…d4

›17.↳ 15The method of claim 15, wherein adding the sender to a list of approved sender addresses includes automatically adding to the list of approved sender …d4

›18.↳ 15The method of claim 15, further comprising adding to the list of approved sender addresses at least one e-mail address obtained from an externally com…d4

›19.↳ 15The method of claim 15, wherein the list of approved sender addresses includes an internally-compiled list of senders for an enterprise e-mail system.d4

›20.↳ 15The method of claim 15, wherein the list of approved sender addresses includes a user-specific list of senders.d4

›21.↳ 15The method of claim 15, wherein the list of approved sender addresses includes both an internally-compiled list of senders for an enterprise e-mail sy…d4

›22.↳ 3The method of claim 3, wherein the instruction to perform the action is presented by an audio file that accompanied the challenge and the correct chal…d3

›23.↳ 3The method of claim 3, wherein the challenge is further accompanied by motion video.d3+2

›26.↳ 1The method of claim 1, further comprising blocking any e-mail message received from any address included on a list of blocked sender addresses without…d2+4

›31.↳ 1The method of claim 1, further comprising:nnotifying the user of receipt of the current e-mail message;prompting the user to indicate whether to send …d2

›32.↳ 1The method of claim 1, wherein the valid challenge key includes a checksum.d2

›33.↳ 1The method of claim 1, wherein the address of a sender of any challenge e-mail response message that includes both the correct challenge response and …d2+1

›35.↳ 1The method of claim 1, wherein the valid challenge key is encrypted.d2

›36.↳ 1The method of claim 1, wherein the valid challenge key includes a random number.d2

›37.independentA system for filtering electronic mail (e-mail) sent to a user comprising:na network that receives and transmits e-mail;a computing device communicati…+4

A system for filtering electronic mail (e-mail) sent to a user comprising:na network that receives and transmits e-mail;a computing device communicatively coupled to the network, the computing device associated with a recipient address and having a plurality of different levels of security ranging from high to low, each level of security associated with a different set of one or more e-mail filters, and wherein the computing device:nreceives a current e-mail message sent over the network from a sender address to the recipient address;determines that a current level of security has been selected by the user, wherein the current level of security as selected by the user is associated with a challenge-response filter,determines that the current e-mail message is not a challenge e-mail response message sent in response to a previous challenge initiated by the computing device, the previous challenge having been identified by a valid challenge key in the previous challenge rendered by the computing device, the valid challenge key identifying a message as a challenge requiring a challenge e-mail response message;sends to the sender address a challenge that requires a correct challenge response, wherein the challenge is selected from a plurality of challenges generated by an external provider of challenges, the external provider being communicatively coupled to the computing device and accessed over the network;stores the current e-mail message from the sender address in an intermediate storage buffer coupled to the computing device;receives a challenge e-mail response message from the sender address; andevaluates the challenge e-mail response message to determine whether the challenge e-mail response message includes a correct challenge response and corresponds to a formal criterion, wherein the formal criterion is a server of the sender address being configured to accept e-mail, wherein future e-mail messages from sender addresses associated with servers that do not accept e-mail are prevented from reaching an intended recipient at the computing device.

›42.independentA non-transitory computer-readable storage medium having embodied thereon a program, the program being executable by a computer to perform a method fo…

Classifications

4 codes

IPC · International Patent Classification

Section G — Physics

G06Q10/10
G06F15/16

Section H — Electricity

H04L12/58

USPC · US Patent Classification

709/206

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Pendency

12.4 y

4,515 days filing → grant

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9

non-final + final

Responses

6

4 RCE

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2

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1

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Examiner

Backhean Tiv

art unit 2451 · TC 2400

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Citations: 204 back · 0 forward

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Priority chain

1 priority documents

›Priority documents — 1

Type	Document	Date
related publication	US 20040015554 A1	22 Jan 2004

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