DETAILED ACTION
This action is in response to the amendments filed on June 17, 2026. Claims 28, 40, and 45-46 have been amended. Claims 1-27 have been previously canceled and claims 28-47 are pending. Claims 28-47 represent a method directed to quantum key distribution.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Specification
Applicant is reminded of the proper language and format for an abstract of the disclosure.
The abstract should be in narrative form and generally limited to a single paragraph on a separate sheet within the range of 50 to 150 words in length. The abstract should describe the disclosure sufficiently to assist readers in deciding whether there is a need for consulting the full patent text for details.
The remaining objections to the disclosure have been withdrawn in view of amendments to the specification.
Claim Objections
The objections to the claims have been withdrawn in view of the amendments to claim 28 and 40.
Claim Rejections - 35 USC § 112
The rejection to the claims have been withdrawn in view of the amendments to the claims.
Response to Arguments
Applicant's arguments filed June 17, 2026, have been fully considered but they are not persuasive.
On pages 11-12 of the Remarks, the applicant argues that the prior art Triandopoulos is nonanalogous art. In response to applicant's argument that Triandopoulos is nonanalogous art, it has been held that a prior art reference must either be in the field of the inventor’s endeavor or, if not, then be reasonably pertinent to the particular problem with which the inventor was concerned, in order to be relied upon as a basis for rejection of the claimed invention. See In re Oetiker, 977 F.2d 1443, 24 USPQ2d 1443 (Fed. Cir. 1992). In this case, Triandopoulos is reasonably pertinent to the particular problem with which the invention is concerned.
The applicant characterizes the particular problem the instant application is solving as “the handling of quantum channel loss events and the obfuscation of sifting announcements”, see Remarks (Page 12). That characterization is drawn from the solution recited in the claim rather than the problem the inventor sets out to address. The problem is identified in the applicant’s own specification. In the Background, the applicant acknowledges the prior ARQ19 protocol, disclosed in GB2590064, as already reducing the information available at the linking nodes, and then states that a further reduction of the information available to the linking nodes is desired. The particular problem is that of preventing a party that receives a set of reported values from determining which of the reported values are genuine.
Triandopoulos is directed to that same problem. As disclosed in the office action submitted on March 27, 2026, on page 10, Triandopoulos discloses the use of honeywords to conceal a real password of a user, in a random position, among a number of fake or decoy passwords, such that a party that obtains the set is unable to distinguish the genuine entry from the fake entries. Triandopoulos refers to its fake entries as decoys and the applicant’s specification likewise refers to the falsely reported symbol locations as “decoy received symbols”.
The applicant further argues that a person of ordinary skill in the field of quantum communications would not look to password authentication literature. The reported symbol numbers recited in claims 28 and 40 are composed and transmitted over a classical communication channel as disclosed in the claims, and no quantum operation is involved in composing or transmitting hem. The limitation is therefore directed to a classical information disclosure problem, and one of ordinary skill in the art would reasonably have looked to the art of concealment of a genuine entry among decoy entries.
On pages 12-13 of the Remarks, the applicant argues that the motivation to combine Triandopoulos with Childe is insufficient. The applicant states that the motivation rests on a mischaracterization because the Childe protocol does not involve passing plaintext passwords to an intermediary. The office action submitted does not find that Childe transmits passwords, and no such finding is necessary. The reference to a plaintext password identifies the subject matter that Triandopoulos protects. The reason for the modification, as stated, is to obscure the data without the intermediary obtaining knowledge of that data. In the combination proposed, the data obscured is the reported symbol numbers of Childe, and the technique taken from Triandopoulos is the inclusion of decoy entries among the genuine entries so that the receiving party cannot determine which entries are genuine. It is not necessary that a password be present in Childe in order for Childe to be modified in accordance with the technique that Triandopoulos teaches.
The applicant further argues that the motivation is not grounded in the teachings of the cited references themselves and that no passage has been identified that would suggest incorporating “not successfully received” symbol indices into a sifting announcement in order to obscure key material positions from the intermediary.
The statement of motivation is supported by a citation to Triandopoulos at Column 23, Lines 52-60, in which the Remarks do not address. That passage states that the use of permuted stored passwords together with the random selection of the chaff passwords ensures that the generation method is location oblivious. The effect of the secret permutation is that the position occupied within the set by any particular password is not determinable by a party in possession of the set. It is noted that the applicant characterizes the purpose of the claimed limitation in the same terms, as obscuring “key material positions” from an intermediary. The reason for the modification is further grounded in the applied art. Childe treats the intermediary device as an untrusted device and states as an object of its protocol that the intermediary not be enabled to determine exactly what the other devices received. The modification applies a known technique to a known method ready for improvement in order to yield that improvement.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 28-47 are rejected under 35 U.S.C. 103 as being unpatentable over Childe et al. (WO 2021090025), hereinafter referred to as Childe, in view of Triandopoulos et al. (US10735403), hereinafter referred to as Triandopoulos.
Regarding Claim 28, Childe discloses:
A computer-implemented method of quantum key distribution between a first device, a second device, and an intermediary device (In the abstract, Childe discloses “Methods, apparatus, and systems are provided for performing a quantum key distribution (QKD) protocol between a first device, a second device, and an intermediary device.”), the method comprising steps of: transmitting, by the intermediary device, a first secret symbol string over a first quantum channel to the first device, wherein each symbol of the first secret symbol string is modulated by a basis state randomly selected from a set of bases (In ¶ 110, Childe discloses “Alice 102a randomly generates the symbols for the first secret symbol stream (e.g. SB), or randomly generates a bit string/stream that is converted into the first secret symbol stream (e.g. SB). Alice 102a sends the first secret symbol string, SB, (e.g. 1 ,000,000 bits, when n=1 ) to Bob 102b over a first quantum channel 104a. For each symbol in SB that is sent to Bob 102b, Alice 102a randomly selects a basis from a set of bases (e.g. B) for modulating said each symbol for transmission over the first quantum channel 104a.”); transmitting, by the intermediary device, a second secret symbol string over a second quantum channel to the second device, wherein each symbol of the second secret symbol string is modulated by a basis state randomly selected from the set of bases (In ¶ 119, Childe discloses “Alice 102a sends a second secret symbol string (e.g. Sc) (e.g. also 1 ,000,000 bits, when n=1 ) to Carol 102c over a second quantum channel 106a. For each symbol in the second secret symbol string (e.g. Sc) that is sent to Carol 102c, Alice 102a randomly selects a basis from the set of bases B for modulating said each symbol for transmission over the second quantum channel 106a.”); demodulating, by the first device, the first secret symbol string, wherein each symbol of the first secret symbol string is demodulated by a basis state randomly selected from the set of bases (In ¶ 113, Childe discloses “Bob 102b demodulates each symbol of the first secret symbol string, SB, received via the first quantum channel 104a by randomly selecting a basis from the set of bases B (e.g. Bob 102b has the same set of bases B as Alice 102a) that is used to demodulate the received symbols from the first quantum channel 104a.”); demodulating, by the second device, the second secret symbol string, wherein each symbol of the second secret symbol string is demodulated by a basis state randomly selected from the set of bases (In ¶ 119, Childe discloses “Carol 102c demodulates each symbol received via the second quantum channel 106a by randomly selecting a basis from the set of bases B that is used to demodulate the received symbols from the second quantum channel 106a.”); transmitting, from the first device to the intermediary device over a first communication channel first, reported symbol numbers, wherein the first reported symbol numbers comprise symbol numbers of symbols of the first secret symbol string that were successfully received by the first device (In ¶ 115, Childe discloses “Bob 102b then sends to Alice 102a over a first classical communication channel 104b an indication of successfully received symbols (e.g. IB) that includes, without limitation, for example data representative of the symbol numbers (e.g. bit numbers) of the successfully received symbols (e.g. #2, #718, #2818, ...)”), transmitting, from the second device to the intermediary device over a second communication channel, second reported symbol numbers, wherein the second reported symbol numbers comprise symbol numbers of the second secret symbol string that were successfully received by the second device (In ¶ 120, Childe discloses “Carol 102c then sends to Alice 102a over a second classical communication channel, set up between Alice 102a and Carol 102c, an indication of successfully received symbols (e.g. Ic) that includes, without limitation, for example data representative data representative of the symbol numbers (e.g. bit numbers) of the successfully received symbols (e.g. #3, #141 ,#5926, ...)”), transmitting, from the intermediary device to the first device over the first communication channel a first basis state set corresponding to the first reported symbol numbers, the first basis state set comprising the basis states used to modulate the symbols of the first secret symbol string, such that the first device can identify validly received symbols from the first secret symbol string to produce a first validly received set of secret symbols (In ¶ 118, Childe discloses “Alice 102a then sends to Bob 102b over the first classical communication channel 104b a first set of bases (e.g. BB) corresponding to each basis state that Alice 102a used to transmit the corresponding symbol of the first set of secret symbols (e.g. XB) in its original transmission (e.g. SB) over the first quantum channel 104a to Bob 102b. Bob 102b then compares the basis that Bob 102b used to demodulate each symbol with the corresponding basis in the received set of bases (e.g. BB) sent by Alice 102a.”); transmitting, from the intermediary device to the second device over the second communication channel, a second basis state set corresponding to the second reported symbol numbers, the second basis state set comprising the basis states used to modulate the symbols of the second secret symbol string, such that the second device can identify the validly received symbols from the second secret symbol string to produce a second validly received set of secret symbols (In ¶ 123, Childe discloses “Alice 102a then sends to Carol 102c over the second classical communication channel 106b a second set of bases (e.g. Be) corresponding to each basis state that Alice 102a used to transmit the corresponding symbol of the second set of secret symbols (e.g. Xc) in its original transmission (e.g. Sc) over the second quantum channel 106a to Carol 102c. Carol 102c then compares the basis that Carol 102a used to demodulate each symbol with the corresponding basis in the received second set of bases (e.g. Be) sent by Alice 102a.”); generating, by the intermediary device, a third symbol string using the first secret symbol string and the second secret symbol string, wherein the third symbol string is generated by: generating a first set of secret symbols comprising symbols of the first secret symbol string that correspond to the first reported symbol numbers (In ¶ 117, Childe discloses “This means that Alice 102a may generate or form a first set of secret symbols (e.g. XB) from the first secret symbol stream (e.g. SB) that were successfully received by Bob 102b using the received symbol numbers representing the symbols Bob 102b successfully received.”); generating a second set of secret symbols comprising symbols of the second secret symbol string that correspond to the second reported symbol numbers (In ¶ 122, Childe discloses “Alice 102a may generate or form a second set of secret symbols (e.g. Xc) from the second secret symbol stream (e.g. Sc) that were successfully received by Carol 102c using the received symbol numbers in Ic representing the symbols Carol 102c successfully received.”); and generating the third symbol string using the first set of secret symbols and the second set of secret symbols (In ¶ 124, Childe discloses “Alice 102a generates a third secret symbol string (e.g. CBC) based on Alice 102a performing a set of processing operations 107 for combining the first set of secret symbols (e.g. XB) with the second set of secret symbols (e.g. Xc) using one or more combining operations.”); transmitting from the intermediary device to the second device over the second communication channel the third symbol string (In ¶ 125, Childe discloses “Alice 102a sends the third secret symbol string (e.g. CBC) to Carol 102c over the second classical communication channel 106b.”), wherein the first device and the second device perform a quantum key exchange based on: generating, by the second device, a fourth set of secret symbols using the third symbol string and symbols corresponding to the second reported symbol numbers or the second validly received set of secret symbols (In ¶ 127, Childe discloses “Carol 102c performs a set of corresponding processing operations 109 for generating a fourth set of secret symbols (e.g. CB.sub.G') using the received second set of secret symbols (e.g. Xcr), which Carol 102c successfully received, and the received third secret symbol string (e.g. CBC).Math.”); wherein the fourth set of secret symbols comprise the symbols of the first device that correspond to the first reported symbol numbers (In ¶ 127, Childe discloses “The fourth set of secret symbols (e.g. CB.sub.G') includes symbols from the first secret set of symbols (e.g. Xer).”); sharing, between the first and the second device over a third communication channel, symbol numbers of the validly received symbols of the received first and the second set of secret symbols (In ¶ 130, Childe discloses “Carol 102c and Bob 102b perform symbol sifting (or bit sifting) or key exchange operations with each other using a third communication channel 108 in which Alice 102a is not a party to.”); and performing a symbol sifting operation by the first device and second device, respectively, by identifying validly received symbols of both the first and second devices that have a common symbol position (In ¶ 133, Childe discloses “On receiving the second set of basis flags (e.g. BFc) from Carol 102c, Bob 102b forms a first common set of secret symbols (e.g. CSB) by comparing each basis flag in the first set of basis flags (e.g. BFB) with each basis flag in the received second set of basis flags from Carol 102c (e.g. BFc) and discards those symbols from the valid first received set of secret symbols (e.g. VB.sub.C) where the corresponding basis flags from the first and received second sets of basis flags (e.g. BFB and BFB) do not match.”), wherein the second device is able to infer, using the fourth set of secret symbols, the validly received symbols of the first device, such that both the first and the second device obtain identical symbols for forming a quantum key (In ¶ 134, Childe discloses “the first and second common sets of secret symbols (e.g. CSB and CSc) and result in a common set of secret symbols from which a cryptographic key, e.g. a final cryptographic key CF, may be produced for Bob 102a and Carol 102c”).
However, Childe does not disclose including unsuccessful symbols.
Triandopoulos discloses:
and symbol numbers of one or more symbols of the first secret symbol string that were not successfully received by the first device (In Col 2, Lines 4-8, Triandopoulos discloses “use of honeywords to conceal a real password of a user (in a random position) in a password file among a number of fake or decoy passwords known as “honeywords” or chaff passwords.” And in Col 2, Lines 37-39 further discloses “generating a chaff set of passwords by modifying portions of the base passwords based on the distribution.”); and symbol numbers of one or more symbols of the second secret symbol string that were not successfully received by the second device (In Col 2, Lines 4-8, Triandopoulos discloses “use of honeywords to conceal a real password of a user (in a random position) in a password file among a number of fake or decoy passwords known as “honeywords” or chaff passwords.” And in Col 2, Lines 37-39 further discloses “generating a chaff set of passwords by modifying portions of the base passwords based on the distribution.”);
One of ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Childe’s approach by utilizing Triandopoulos’ approach of modifying a password that would be passed to an intermediatory to include decoy or dummy data as the motivation would be to obscure the data without the intermediatory obtaining the knowledge of the plaintext password (See Triandopoulos, Col 23, Lines 52-60)
Regarding Claim 29, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein a symbol is a bit. (In ¶ 116, Childe discloses “when n=1 bit per symbol i.e. a symbol is a bit”)
Regarding Claim 30, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the intermediary device comprises two or more nodes. (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 31, the combination of Childe and Triandopoulos disclose:
The method of claim 30, wherein each node is configured to receive data from an adjacent node and/or the first or the second device (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 32, the combination of Childe and Triandopoulos disclose:
The method of claim 30, wherein each node is configured to transmit data to an adjacent node and/or the first or the second device (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 33, the combination of Childe and Triandopoulos disclose:
The method of claim 32, wherein the two or more nodes comprise: a first node which transmits the first secret symbol string and the first basis state set to the first device, and receives the first reported symbol numbers transmitted from the first device; and a second node which transmits the second secret symbol string, the second basis state set, and the third symbol string to the second device, receives the second reported symbol numbers transmitted from the second device, and generates the third symbol string; wherein the first node transmits the first set of secret symbols, or the first secret symbol string and the first reported symbol numbers, to the second node. (In ¶ 138, Childe discloses “Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2), for obtaining cryptographic keys (e.g. Ci and C2) from each. The at least two different intermediary devices 102a and 102d (e.g. A1 and A2) are configured to perform a first QKD protocol instantiation 110a and a second QKD protocol instantiation 110b, respectively, with Bob 102a and Carol 102c based on the QKD protocol as described with reference to figure 1 a.”)
Regarding Claim 34, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the third symbol string is generated based on performing an XOR operation of symbols comprising the first set of secret symbols and the second set of secret symbols (In ¶ 181, Childe discloses “generating the third symbol string based on performing an XOR operation using data representative of, at least in part, the first secret symbol string and the second secret symbol string;”)
Regarding Claim 35, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the third symbol string is generated based on performing a one-time pad encryption operations(s) of symbols comprising first set of secret symbols and the second set of secret symbols (In ¶ 26, Childe discloses “generating the third symbol string based on performing one time pad encryption operation(s) using data representative of, at least in part, the first secret symbol string and the second secret symbol string;”)
Regarding Claim 36, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the third symbol string is generated based on performing an operation for obfuscating one or more symbols of the first set of secret symbols using the second set of secret symbols (In ¶ 26, Childe discloses “generating the third symbol string based on performing one time pad encryption operation(s) using data representative of, at least in part, the first secret symbol string and the second secret symbol string;”)
Regarding Claim 37, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the fourth set of secret symbols is generated based on performing an XOR operation of symbols comprising the third symbol string and the symbols corresponding to the second reported symbol numbers or the second validly received set of secret symbols (In ¶ 18, Childe discloses “generating the fourth symbol string based on performing an XOR operation using data representative of, at least in part, the second secret symbol string and the third symbol string;”)
Regarding Claim 38, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the fourth set of secret symbols is generated based on performing a one-time pad decryption operations(s) of symbols comprising the third symbol string and the symbols corresponding to the second reported symbol numbers or the second validly received set of secret symbols (In ¶ 36, Childe discloses “generating the fourth symbol string based on performing one time pad decryption operation(s) using data representative, of at least in part, the received second secret symbol string and the received third secret symbol string”)
Regarding Claim 39, the combination of Childe and Triandopoulos disclose:
The method of claim 28, wherein the fourth set of secret symbols is generated based on performing an operation for extracting one or more symbols corresponding to the second reported symbol numbers or second validly received set of secret symbols using the third symbol string (In ¶ 18, Childe discloses “generating the fourth symbol string based on performing any other type of operation for extracting one or more symbols of the first secret symbol string using data representative of, at least in part, the second secret symbol string and the third symbol string.”)
Regarding Claim 40, Childe discloses:
A computer-implemented method of quantum key distribution between a first device, a second device, and an intermediary device (In the abstract, Childe discloses “Methods, apparatus, and systems are provided for performing a quantum key distribution (QKD) protocol between a first device, a second device, and an intermediary device.”), the method comprising steps of: transmitting, by the intermediary device, a first secret symbol string over a first quantum channel to the first device, wherein each symbol of the first secret symbol string is modulated by a basis state randomly selected from a set of bases (In ¶ 110, Childe discloses “Alice 102a randomly generates the symbols for the first secret symbol stream (e.g. SB), or randomly generates a bit string/stream that is converted into the first secret symbol stream (e.g. SB). Alice 102a sends the first secret symbol string, SB, (e.g. 1 ,000,000 bits, when n=1 ) to Bob 102b over a first quantum channel 104a. For each symbol in SB that is sent to Bob 102b, Alice 102a randomly selects a basis from a set of bases (e.g. B) for modulating said each symbol for transmission over the first quantum channel 104a.”); transmitting, by the intermediary device, a second secret symbol string over a second quantum channel to the second device, wherein each symbol of the second secret symbol string is modulated by a basis state randomly selected from the set of bases (In ¶ 119, Childe discloses “Alice 102a sends a second secret symbol string (e.g. Sc) (e.g. also 1 ,000,000 bits, when n=1 ) to Carol 102c over a second quantum channel 106a. For each symbol in the second secret symbol string (e.g. Sc) that is sent to Carol 102c, Alice 102a randomly selects a basis from the set of bases B for modulating said each symbol for transmission over the second quantum channel 106a.”); demodulating, by the first device, the first secret symbol string, wherein each symbol of the first secret symbol string is demodulated by a basis state randomly selected from the set of bases (In ¶ 113, Childe discloses “Bob 102b demodulates each symbol of the first secret symbol string, SB, received via the first quantum channel 104a by randomly selecting a basis from the set of bases B (e.g. Bob 102b has the same set of bases B as Alice 102a) that is used to demodulate the received symbols from the first quantum channel 104a.”); demodulating, by the second device, the second secret symbol string, wherein each symbol of the second secret symbol string is demodulated by a basis state randomly selected from the set of bases (In ¶ 119, Childe discloses “Carol 102c demodulates each symbol received via the second quantum channel 106a by randomly selecting a basis from the set of bases B that is used to demodulate the received symbols from the second quantum channel 106a.”); transmitting, from the first device to the intermediary device over a first communication channel first reported symbol numbers, wherein the first reported symbol numbers comprise symbol numbers of symbols of the first secret symbol string that were successfully received by the first device(In ¶ 115, Childe discloses “Bob 102b then sends to Alice 102a over a first classical communication channel 104b an indication of successfully received symbols (e.g. IB) that includes, without limitation, for example data representative of the symbol numbers (e.g. bit numbers) of the successfully received symbols (e.g. #2, #718, #2818, ...)”); transmitting from the second device to the intermediary device over a second communication channel, second reported symbol numbers, wherein the second reported symbol numbers comprise symbol numbers of the second secret symbol string that were successfully received by the second device (In ¶ 120, Childe discloses “Carol 102c then sends to Alice 102a over a second classical communication channel, set up between Alice 102a and Carol 102c, an indication of successfully received symbols (e.g. Ic) that includes, without limitation, for example data representative data representative of the symbol numbers (e.g. bit numbers) of the successfully received symbols (e.g. #3, #141 ,#5926, ...)”); transmitting, from the intermediary device to the first device over the first communication channel, a first basis state set corresponding to the first reported symbol numbers, the first basis state set comprising the basis states used to modulate the symbols of the first secret symbol string, such that the first device can identify validly received symbols from the first secret symbol string to produce a first validly received set of secret symbols (In ¶ 118, Childe discloses “Alice 102a then sends to Bob 102b over the first classical communication channel 104b a first set of bases (e.g. BB) corresponding to each basis state that Alice 102a used to transmit the corresponding symbol of the first set of secret symbols (e.g. XB) in its original transmission (e.g. SB) over the first quantum channel 104a to Bob 102b. Bob 102b then compares the basis that Bob 102b used to demodulate each symbol with the corresponding basis in the received set of bases (e.g. BB) sent by Alice 102a.”); transmitting, from the intermediary device to the second device over the second communication channel, a second basis state set corresponding to the second reported symbol numbers, the second basis state set comprising the basis states used to modulate the symbols of the second secret symbol string, such that the second device can identify the validly received symbols from the second secret symbol string to produce a second validly received set of secret symbols (In ¶ 123, Childe discloses “Alice 102a then sends to Carol 102c over the second classical communication channel 106b a second set of bases (e.g. Be) corresponding to each basis state that Alice 102a used to transmit the corresponding symbol of the second set of secret symbols (e.g. Xc) in its original transmission (e.g. Sc) over the second quantum channel 106a to Carol 102c. Carol 102c then compares the basis that Carol 102a used to demodulate each symbol with the corresponding basis in the received second set of bases (e.g. Be) sent by Alice 102a.”), wherein the first and the second device use a shared symmetric key to generate common symbol positions to position their validly received symbols (In ¶ 228, Childe discloses “The communications over one or more of: the first quantum channel, the second quantum channel, the first communication channel, the second communication channel and/or the third communication channel; may be, without limitation, for example encrypted communications with pre-shared keys between the corresponding intermediary device, the first device, and/or the second device and/or as the application demands.”); transmitting, from the first device to the intermediary device via the first communication channel a third basis state set, wherein the third basis state set comprises the basis states used to modulate the validly received symbols of the first secret symbol string, and one or more basis states corresponding to symbols from the first secret symbol string that were successfully received, but not validly received, and/or one or more basis states corresponding to symbols from the first secret symbol string that were not successfully received (In ¶ 130, Childe discloses “Bob 102b formed a first set of basis flags (e.g. BFB) including a plurality of indications/flags corresponding to each symbol of the first received set of secret symbols (e.g. Xer), where each indication/flag for a symbol includes data representative of whether that symbol in the first received set of secret symbols (e.g. Xe.sub.r) was validly received or not based on the comparison of bases”); transmitting, from the second device to the intermediary device via the second communication channel a fourth basis state set, wherein the fourth basis state set comprises the basis states used to modulate the validly received symbols of the second secret symbol string, and one or more basis states corresponding to symbols from the second secret symbol string that were successfully received, but not validly received, and/or one or more basis states corresponding to symbols from the second secret symbol string that were not successfully received (In ¶ 131, Childe discloses “Carol 102c formed a second set of basis flags (e.g. BFc) including a plurality of indications/flags corresponding to each symbol of the second received set of secret symbols (e.g. Xcr), where each indication/flag for a symbol includes data representative of whether that symbol in the second received set of secret symbols (e.g. Xcr) was validly received or not based on the comparison of bases”); generating, by the intermediary device, a third symbol string using the first secret symbol string and the second secret symbol string, wherein the third symbol string is generated by: generating a first set of secret symbols comprising symbols of the first secret symbol string that correspond to the third basis state set (In ¶ 117, Childe discloses “This means that Alice 102a may generate or form a first set of secret symbols (e.g. XB) from the first secret symbol stream (e.g. SB) that were successfully received by Bob 102b using the received symbol numbers representing the symbols Bob 102b successfully received.”); generating a second set of secret symbols comprising symbols of the second secret symbol string that correspond to the fourth basis state set (In ¶ 122, Childe discloses “Alice 102a may generate or form a second set of secret symbols (e.g. Xc) from the second secret symbol stream (e.g. Sc) that were successfully received by Carol 102c using the received symbol numbers in Ic representing the symbols Carol 102c successfully received.”) shifting the first and the second set of secret symbols to produce, respectively, a first and a second set of shifted secret symbols; and generating the third symbol string using the first and a second set of shifted secret symbols (In ¶ 138, Childe discloses “Carol 102c may perform a similar set of operations, by converting the received third secret symbol string into a received third secret bit string and perform a bitwise XOR operation using the received third secret bit string”); and transmitting from the intermediary device to the second device over the second communication channel the third symbol string (In ¶ 125, Childe discloses “Alice 102a sends the third secret symbol string (e.g. CBC) to Carol 102c over the second classical communication channel 106b.”); and generating, by the second device, a fourth set of secret symbols using the third symbol string and the symbols corresponding to the fourth basis state set or the second validly received set of secret symbols, wherein the second device is able to infer, using the fourth set of secret symbols, the symbols of the first device that correspond to the third basis state set, such that both the first and the second device obtain identical symbols for forming a quantum key (In ¶ 134, Childe discloses “the first and second common sets of secret symbols (e.g. CSB and CSc) and result in a common set of secret symbols from which a cryptographic key, e.g. a final cryptographic key CF, may be produced for Bob 102a and Carol 102c”).
However, Childe does not disclose including unsuccessful symbols.
Triandopoulos discloses:
and symbol numbers of one or more symbols of the first secret symbol string that were not successfully received by the first device (In Col 2, Lines 4-8, Triandopoulos discloses “use of honeywords to conceal a real password of a user (in a random position) in a password file among a number of fake or decoy passwords known as “honeywords” or chaff passwords.” And in Col 2, Lines 37-39 further discloses “generating a chaff set of passwords by modifying portions of the base passwords based on the distribution.”); and symbol numbers of one or more symbols of the second secret symbol string that were not successfully received by the second device (In Col 2, Lines 4-8, Triandopoulos discloses “use of honeywords to conceal a real password of a user (in a random position) in a password file among a number of fake or decoy passwords known as “honeywords” or chaff passwords.” And in Col 2, Lines 37-39 further discloses “generating a chaff set of passwords by modifying portions of the base passwords based on the distribution.”);
One of ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Childe’s approach by utilizing Triandopoulos’ approach of modifying a password that would be passed to an intermediatory to include decoy or dummy data as the motivation would be to obscure the data without the intermediatory obtaining the knowledge of the plaintext password (See Triandopoulos, Col 23, Lines 52-60)
Regarding Claim 41, the combination of Childe and Triandopoulos disclose:
The method of claim 40, wherein a symbol is a bit. (In ¶ 116, Childe discloses “when n=1 bit per symbol i.e. a symbol is a bit”)
Regarding Claim 42, the combination of Childe and Triandopoulos disclose:
The method of claim 40, wherein the intermediary device comprises one or more nodes. (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 43, the combination of Childe and Triandopoulos disclose:
The method of claim 42, wherein each node is configured to receive data from an adjacent node and/or the first or the second device. (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 44, the combination of Childe and Triandopoulos disclose:
The method of claim 42, wherein each node is configured to transmit data to an adjacent node and/or the first or the second device. (In ¶ 138, Childe discloses “In this case, Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2),”)
Regarding Claim 45, the combination of Childe and Triandopoulos disclose:
The method of claim 44, wherein the one or more nodes comprise: a first node which transmits the first secret symbol string and the first basis state set to the first device, and receives the first reported symbol numbers and the third basis state set transmitted from the first device; and a second node which transmits the second secret symbol string, the second basis state set, and the third symbol string to the second device, receives the second reported symbol numbers and the fourth basis state set transmitted from the second device, and generates the third symbol string; wherein the first node transmits the first set of secret symbols, or the first secret symbol string and the third basis state set, to the second node. (In ¶ 138, Childe discloses “Bob 102b (first device 102b) and Carol 102c (second device 102c) may use two different providers of QKD services or at least two different intermediary devices 102a and 102d (e.g. A1 and A2), for obtaining cryptographic keys (e.g. Ci and C2) from each. The at least two different intermediary devices 102a and 102d (e.g. A1 and A2) are configured to perform a first QKD protocol instantiation 110a and a second QKD protocol instantiation 110b, respectively, with Bob 102a and Carol 102c based on the QKD protocol as described with reference to figure 1 a.”)
Regarding Claim 46, the combination of Childe and Triandopoulos disclose:
The method of claim 40, wherein the third symbol string is generated based on performing an XOR operation of symbols comprising the first set of shifted secret symbols and the second set of sifted secret symbols (In ¶ 181, Childe discloses “generating the third symbol string based on performing an XOR operation using data representative of, at least in part, the first secret symbol string and the second secret symbol string;”)
Regarding Claim 47, the combination of Childe and Triandopoulos disclose:
The method of claim 40, wherein the third symbol string is generated based on performing a one-time pad encryption operations(s) of symbols comprising first set of shifted secret symbols and the second set of shifted secret symbols (In ¶ 26, Childe discloses “generating the third symbol string based on performing one time pad encryption operation(s) using data representative of, at least in part, the first secret symbol string and the second secret symbol string;”)
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Jacobs, Bryan (US 8693691) discloses a methods and systems to authenticate systems in a quantum key distribution environment based on limited disclosures and identical, re-usable, pre-provisioned authentication keys, each system constructs an encryption key based on a corresponding one of transmitted events and detected events.
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/SHADI H KOBROSLI/Examiner, Art Unit 2492 /RUPAL DHARIA/Supervisory Patent Examiner, Art Unit 2492
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