DETAILED ACTION
This action is in response to the remarks filed on May 26, 2026. Claims 1-20 are pending. Of such, claims 1-6 represent a system, claims 7-13 represent a method, and claims 14-20 represent a non-transitory computer readable medium directed to encrypted information sharing with lightweight devices.
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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on May 26, 2026 has been entered.
Response to Arguments
Applicant's arguments filed May 26, 2026 have been fully considered but they are not persuasive.
On page 2 of the Remarks, the Applicant states that Le Saint (¶ 204) discloses “the MAC 1222 may be generated using the same key or a different key than the key used to generate the cipher text” is permissive rather than prescriptive. This argument is not persuasive.
Le Saint explicitly discloses a number of alternatives which suggests each of them, the use of the same key alternative is a choice among the alternatives disclosed. The Applicant identifies nothing in Le Saint that teaches away the use of the same key to generate the cipher text and Le Saint (¶ 204) affirmatively contemplates it.
On page 2 of the Remarks, the Applicant states that Bhattacharyya is applied only for derivation of a symmetric key using a cryptographic hash or one-way function (¶ 47) and does not describe how a MAC is generated or keyed. This argument is not persuasive.
Bhattacharyya is applied for the key-generation limitation only; no MAC limitation is mapped to Bhattacharyya. In response to applicant's arguments against the references individually, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986).
On pages 2-3 of the Remarks, the applicant contends Ginzboorg’s pre-shared group key and use of a plaintext message as a MAC input. This combination is not applied in the rejection that follows and is thus moot in view of the amendments to the claims.
However, upon further consideration, a new ground(s) of rejection is made in view of Le Saint, Bhattacharyya, Cachin, and Gilton.
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.
Claims 1-4, 7-10, 13-17, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Le Saint et al. (US 20160218875), hereinafter referred to as Le Saint, in view of Bhattacharyya et al. (US 20200252396), hereinafter referred to as Bhattacharyya, in further view of Cachin et al. (US 20080172562), hereinafter referred to as Cachin.
Regarding Claim 1, Le Saint discloses:
A system comprising: a memory; and a processor (In ¶ 86, Le Saint discloses “Server computer 300 may include a processor 301 communicatively coupled to a network interface 302, a memory 303, a computer readable medium 310, and optionally, a secure element 304.”) configured to: receive, by a sender, a public key of a recipient (In ¶ 12, Le Saint discloses “A server computer can receive a provisioning request message from a user device including a one-time user public key.”); generate, by the sender, a symmetric key using the public key of the recipient and a private key of the sender as inputs to a key generation algorithm (In ¶ 12, Le Saint discloses “A response shared secret can be generated using a static server private key and the one-time user public key.” And further in ¶ 83 discloses “Encryption module 212 may be further configured to derive a session key or storage protection key from a shared secret, such as using a key derivation function (KDF).”), encrypt, by the sender, a message using the symmetric key to generate an encrypted message (In ¶ 12, Le Saint discloses “The provisioning response message can be encrypted using the response session key to generate encrypted provisioning response message, wherein the provisioning response message includes the encrypted credential data.”); and transmit, by the sender, a second public key of the sender, the MAC, and the encrypted message to the recipient in a response, the second public key of the sender corresponding to the private key of the sender (In ¶ 205, Le Saint discloses “The provisioning response message 1210 corresponding to the provisioning request message 1202 may also include three data portions: a clear text portion 1212, a cipher text portion 1214, and a MAC 1216. The clear text portion 1212 can include a server public key (that may be blinded in some embodiments) and encrypted credential data 1218.” And in ¶ 14 “blinded static server public key corresponding to the static server private key.”).
However, Le Saint does not explicitly disclose the hash function to generate the symmetric key.
Bhattacharyya discloses:
the key generation algorithm comprising a hash function applied to a combination of the public key and the private key (In ¶ 47, Bhattacharyya discloses “At block 410, the device derives a symmetric cryptographic key from the shared secret using a key derivation algorithm, cryptographic hash, or one-way function.”)
One in ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Le Saint’s approach by utilizing Bhattacharyya’s approach of hash based key generation as the motivation would be that the receiver would be able to perform a key derivation function to derive the symmetric key used to decrypt the message (See Bhattacharyya, ¶ 57).
However, Le Saint does not explicitly disclose the generation of the Message Authentication Code using the encrypted message and key as inputs.
Cachin discloses:
generate a message authentication code (MAC) using the symmetric key and the encrypted message as inputs to a MAC generation function (In ¶ 31, Cachin discloses “the plaintext data block P1 and a (short) secret key K and outputs a ciphertext, i.e. an encrypted data block C1, and a (short) authentication tag 1”); wherein the symmetric key used as an input to the MAC generation function is the same symmetric key that was used to generate the encrypted message (In ¶ 31, Cachin discloses “The authenticated encryption S1 with the same key K”)
One in ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Le Saint’s approach by utilizing Cachin’s approach of computing a MAC over the transmitted ciphertext using a single symmetric key via a GCM-mode encryption construction to authenticate the ciphertext as the motivation would be that ease of using a single key allows for efficiency, time saving, and ease of implementation (See Cachin, ¶¶ 4-5).
Regarding Claim 2, the combination of Le Saint, Bhattacharyya, and Cachin disclose:
The system of claim 1, wherein the public key of the recipient comprises an elliptic curve cryptography (ECC) public key and the second public key of the sender comprises a second ECC public key (In ¶ 36, Le Saint discloses “Public and private keys may be in any suitable format, including those based on RSA or elliptic curve cryptography (ECC).”).
Regarding Claim 3, the combination of Le Saint, Bhattacharyya, and Cachin disclose:
The system of claim 1, wherein generating the symmetric key comprises generating the symmetric key using the public key of the recipient and a private key of the sender (In ¶ 12, Le Saint discloses “A response shared secret can be generated using a static server private key and the one-time user public key.”), the private key of the sender corresponding to the second public key (In ¶ 14, Le Saint discloses “The provisioning response message can include a blinded static server public key corresponding to the static server private key.”)
Regarding Claim 4, the combination of Le Saint, Bhattacharyya, and Cachin disclose:
The system of claim 3, further comprising a second processor configured to: re-calculate a second symmetric key using a private key of the recipient and the second public key (In ¶ 122, Le Saint discloses “ In some embodiments, the response shared secret may be generated from the user private key and the blinded static server public key using any suitable method, such as ECDH” and further in ¶ 124 “ At block 510, a response session key is determined using the response shared secret and other suitable supplementary data such as key derivation data, if any”); and decrypting the encrypted message using the second symmetric key (In ¶ 126, Le saint discloses “the provisioning response message is decrypted using the response session key to obtain response data.)”
Claims 7-10 are directed to a method having functionality corresponding to the system of Claims 1-4, respectively, and are rejected by a similar rationale, mutatis mutandis.
Regarding Claim 13, the combination of Le Saint, Bhattacharyya, and Cachin disclose:
The method of claim 7, and transmitting the MAC to the recipient along with the second public key of the sender and the encrypted message (In ¶ 205, Le Saint discloses “The provisioning response message 1210 corresponding to the provisioning request message 1202 may also include three data portions: a clear text portion 1212, a cipher text portion 1214, and a MAC 1216. The clear text portion 1212 can include a server public key (that may be blinded in some embodiments) and encrypted credential data 1218.”).
However, Le Saint does not explicitly disclose the encryption and signing of the keys.
Cachin discloses:
further comprising generating a message authentication code (MAC) using the symmetric key (In ¶ 31, Cachin discloses “the plaintext data block P1 and a (short) secret key K and outputs a ciphertext, i.e. an encrypted data block C1, and a (short) authentication tag 1”)
One in ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Le Saint’s approach by utilizing Cachin’s approach of computing a MAC over the transmitted ciphertext using a single symmetric key via a GCM-mode encryption construction to authenticate the ciphertext as the motivation would be that ease of using a single key allows for efficiency, time saving, and ease of implementation (See Cachin, ¶¶ 4-5).
Claims 14-17 are directed to a non-transitory computer readable medium having functionality corresponding to the system of Claims 1-4, respectively, and are rejected by a similar rationale, mutatis mutandis.
Claim 20 is directed to a method having functionality corresponding to the method of Claim 13 and is rejected by a similar rationale, mutatis mutandis.
Claims 5-6, 11-12, and 18-19 are rejected under 35 U.S.C. 103 as being unpatentable over Le Saint et al. (US 20160218875), hereinafter referred to as Le Saint, in view of Bhattacharyya et al. (US 20200252396), hereinafter referred to as Bhattacharyya, in further view of Cachin et al. (US 20080172562), hereinafter referred to as Cachin, in further view of Gilton et al. (US 20210099292), hereinafter referred to as Gilton.
Regarding Claim 5, the combination of Le Saint, Bhattacharyya, and Cachin disclose the limitations of Claim 1.
However, Le Saint does not explicitly disclose the encryption and signing of the keys.
Gilton discloses:
encrypt, by the sender, the symmetric key using the public key of the recipient to generate an encrypted symmetric key (In ¶ 62, Gilton discloses “The encryption module 308 then encrypts the generated session key with the received device public key.”); sign, by the sender, the symmetric key using a private key of the sender to generate a digital signature (In ¶ 62, Gilton discloses “the key signing module 306 signs a combination of the received device nonce and the generated session key (e.g., a concatenation of the device nonce and the session key) with the server private key.”); and transmit the digital signature and the encrypted symmetric key to the recipient along with the second public key of the sender and the encrypted message (In ¶ 62, Bhattacharyya discloses “transmits the device nonce, the signed combination of the device nonce and the session key, and the encrypted session key to the DCM 202.”).
One in ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Le Saint’s approach by utilizing Gilton’s approach of digital signatures and encryption as the motivation would be that the signing a combination including the session key with the server private key prevents the session key from being replaced if the communication is intercepted. (See Gilton, ¶¶ 62-63).
Regarding Claim 6, the combination of Le Saint, Bhattacharyya, and Cachin disclose the limitations of Claim 5.
However, Le Saint does not explicitly disclose the encryption and signing of the keys.
Gilton discloses:
The system of claim 5, further comprising a second processor configured to: validate the digital signature using the second public key of the sender (In ¶ 63, Gilton discloses “uses the server public key to read the signed combination of the device nonce and the session key to obtain a validated device nonce and a validated session key.”); decrypt the encrypted symmetric key using a private key of the recipient to obtain a decrypted symmetric key; and decrypt the encrypted message using the decrypted symmetric key (In ¶ 63, Gilton discloses “The verification module 412 uses the device private key to decrypt the encrypted session key and verifies that the result matches the validated session key.”).
One in ordinary skill in the art of cryptography would have been motivated, before the effective filing date of the claimed invention to modify Le Saint’s approach by utilizing Gilton’s approach of digital signatures and encryption as the motivation would be that the signing a combination including the session key with the server private key prevents the session key from being replaced if the communication is intercepted. (See Gilton, ¶¶ 62-63).
Claims 11 and 12 are directed to a method having functionality corresponding to the system of Claims 5 and 6, respectively, and are rejected by a similar rationale, mutatis mutandis.
Claims 18 and 19 are directed to a non-transitory computer readable medium having functionality corresponding to the system of Claims 5 and 6, respectively, and are rejected by a similar rationale, mutatis mutandis.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
Sherkin et al. (US 20170357819) discloses a peer to peer encrypted message communication method.
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/SHADI H KOBROSLI/Examiner, Art Unit 2492 /RUPAL DHARIA/Supervisory Patent Examiner, Art Unit 2492
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