DETAILED ACTION
1. This office action is in response to an amendment filed on 05/04/2026. New dependent claim 10 is added. Thus claims 1-10 are pending and claim 1 is amended.
Notice of Pre-AIA or AIA Status
2. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
3. The information disclosure statements (IDS), filed on 05/04/2026 has been considered. The submission is in compliance with the provisions of 37 CFR 1.97. Form PTO-1449 is signed and attached hereto.
Response to Arguments
4. Referring to the independent claims 1 and the corresponding dependent claims 2-9 associated 35 U.S.C. 103 rejection, applicant’s remarks/arguments filed on May 4, 2026 have also been fully considered but aren’t persuasive.
Applicant attacks Jakobsson and Nakamoto individually and reads Jakobsson paragraphs [0024] and [0045] in isolation, whereas the rejection is based on the combined teachings of the references.
Applicant’s argument regarding independent claim 1,
Contrary to Applicant’s position, Jakobsson expressly teaches deriving a cryptographic challenge from both ledger information and transaction or event information. Paragraph 0025 states that “c is computed as the hash” of the most recent ledger entry together with the transactions signed in that ledger entry. Para. 0044 additionally teaches allowing selected transactions to contribute to and modify the challenge, while para. 0047 teaches generating a global challenge from ledger entries and expressly states that the local challenge may simply be the global challenge. Paragraph 0062 teaches that detecting an event causes and event-notification transaction to be added to the next transaction set. Accordingly, Jakobsson’s challenge is based on ledger state and event-related transaction information. The fact that the personalized challenge of paragraph 0045 may additionally depend on graph or mining-instance information does not negate that teaching because claim 1 requires only that the challenge be “based on” the hash chain and event; it does not require those to be the exclusive inputs.
Applicant’s distinction between Nakamoto’s block header and transaction body is also unpersuasive. Nakamoto explains that “transactions are hashed in a Merkle Tree…with only the root included in the block’s hash,” and its block-header diagram includes both the previous-block hash and the transaction root. Nakamoto’s proof-of-work is obtained by changing the nonce until that block hash stratifies the difficulty requirement. Thus, the proof-of-work instance is cryptographically dependent on both the previous-hash chain and the transaction or event content committed through the Merkle root. The claim does not require the raw event data itself to appear in the header.
Furthermore, the claimed ordering is likewise taught. Nakamoto first collects transactions into a candidate block, then performs proof-of-work for that block, then broadcasts the completed block for validation and addition to the chain. Jakobsson expressly states that its techniques apply to proof-of-work systems and may be used to retrofit such systems, while identifying reduced griding as a reason to bind a challenge to ledger and transaction information. This supplies an express, nonconclusory motivation to apply Jakobsson’s ledger-derived challenge to Nakamoto’s proof-of-work ledger.
In order to clarify the rejection and to show how the combination of Jakobsson and Nakamoto teaches all the limitation of at least independent claim 1, the office maps the combination of the prior art to each claim limitation as follows:
As per independent claim 1, Jakobsson discloses a device configured to implement a distributed ledger capable of immutably recording a hash chain [Para. 0003,. Discloses an apparatus implementing a mining system associated with a distributed ledger. Nakamoto also on abstract and section 3-4, teaches timestamping transactions into an ongoing hash-based proof of work chain that can not be changed without redoing the proof of work and taches including the previous timestamp’s hash in each subsequent timestamp. Together the references teach a device implementing an immutable distributed hash-chain ledger], the device comprising: a network interface memory and a processor [Para. 0067, discloses a processing device having a processor 910 coupled to a memory 912 and a network interface 914]
the processor configured to:
obtain a ledger entry the ledger entry comprising: a hash chain and an event [Para 0027, discloses a ledger entry containing a first signature associated with the previous ledger entry and a transaction set or references to the transactions. Para. 0062, teaches that detection of a publicly verifiable event results in an event-notification transaction being added to a transaction set. Furthermore, Nakamoto section 3 and 7 supplies that explicit hash-chain implementation through the previous block hash and the transaction commitment. Thus the combined ledger record contains both a link to the hash chain and event related transaction data.]
obtain a challenge using a cryptographic system wherein the challenge is based on the hash chain and the event [Para. 0025 teaches cryptographically hashing the most recent ledger entry together with transactions signed in that entry to compute challenge C. Para. 0044, teaches using transaction information as input that modifies the challenge, and para. 0047 teaches deriving the global challenge from ledger entries. Note: in Nakamoto, the candidate block hash includes the previous-block hash includes and the Merkle root committing to the event transactions. Consequently, the challenge presented by the combined system is based on both hash-chain state and event content];
broadcast a block that incorporates the ledger entry to securely add the block to a distributed ledger [Nokamoto section 5, teaches collecting new transactions into a block, finding proof-of-work for that block, broadcasting the block to the network, validating the transactions and extending the chain using the accepted blocks hash. The broadcast block therefore incorporates the ledger or even records and is securely added to the distributed ledger.]
wherein the block is capable of being validated by using a cryptographic system to obtain a proof based on the challenge [Para. 0003, teaches generating a proof in response to a challenge. Para. 0024-0025 teaches producing a witness or proof responsive to the challenge and cryptographically verifying that the witness matches the challenge and associated ledger transactions and Nakamoto section 4-5 further teaches cryptographic verification of proof of work and acceptance of a block only after validation.]
Applicant’s argument regarding dependent claims 2-9,
Examiner would like to point out that, applicant provide no separate substantive argument for claims 2-7, but relies on the alleged deficiency of claim 1. Because that alleged deficiency is not present, the derivative argument does not overcome the rejections. Nakamoto additionally teaches the iterative nonce-and-hash process of claim 2 and a difficulty or hardness target adjustment according to block-generation rate for claim 3.
Applicant’s arguments concerning claims 8 and 9 are not commensurate with the scope of those claims. Neither claim requires a witness, elimination of verifier re-computation, or reduced verification cost.
Yakovenko expressly teaches an iterative hash sequence in which each iteration uses “an output from a previous iteration as its input” expressly identifies a proof of history generator, mixes hashes of events into the sequence, and uses that sequences to determine the “temporal order of event data” whether one disclosed verification embodiment recomputes portions of the sequence does not remove these express teachings. Moreover, Jakobsson’s Merkle-tree structure is immaterial because Yakovenko-not Jakobsson-is relied upon the linear, iterative proof-of-history hash chain event ordering.
.5. From the above understanding the rejection set forth in the previous office action is maintained. Applicant’s representative is encouraged to call to the office and schedule a telephone interview to discuss this case further. In particular to discuss how the claims could be amended to overcome the ground of rejection.
Claim Rejections - 35 USC § 103
6. 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.
The factual inquiries set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or non-obviousness.
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 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.
7. Claims 1-3 are rejected under 35 U.S.C. 103 as being unpatentable over Bjorn Markus Jakobsson (herein after referred as Jakobsson) (US Publication No. 2019/0324995 A1) (Published on Oct. 24, 2019) in view of NPL document, titled, “Bitcoin: A Peer-to-Peer Electronic Cash System” by Satoshi Nakamoto (2008) (herein after referred as Nakamoto).
The following is referring to independent claim 1:
As per independent claim 1, Jakobsson discloses a device configured [Para. 0003, an apparatus comprises at least one processing device comprising a processor coupled to a memory. The at least one processing device implements a mining operator entity configured. The apparatus comprising the processing device implementing a mining operator entity meets the limitation, “device”] to implement a distributed ledger [Para. 0003, an apparatus comprises at least one processing device comprising a processor coupled to a memory. The at least one processing device implements a mining operator entity configured to instantiate one or more mining instances configured to generate one or more proofs of space …in response to a challenge, the challenge being computed at least in part from one or more ledger values of a distributed ledger.] capable of immutably recording a hash chain [Para. Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 meets the limitation, “hash chain”. Furthermore, Para. 0026, “a witness corresponds to the triple (P, pk, i), and is submitted by the miner to the ledger along with a Merkle signature using public key pk on the most recent set of transactions T that have not been signed in previous ledger entries… “To verify a ledger entry of this type, a verifier generates a leaf from (R, P, pk, i), determines that this leaf value matches the challenge c, and verifies that the associated Merkle signature using pk is a valid signature on the concatenation of the most recent ledger entry and the set T′ of transactions signed in the most recent ledger entry”. Examiner Note: each ledger entry contains -a Merkle signature (which commits to the entire Merkle hash structure: and it itself part of the distributed ledger. This meets the “immutably recording a hash chain” since once the entry with the Merkle signature is added, the committed Merkle tree (hash chain) is locked and verifiable], the device [Figure 9, ref. 902-1, “processing device”] comprising: a network interface [Figure 9, ref. 914, “network interface”]; memory [Figure 9, ref 912, “Memory”]; and a processor [Figure 9, ref. 910, “processor”], the processor configured to:
obtain a ledger entry [ Para. 0025, see how the verifier obtains/retrieve and verify T, the transaction set with is part of ledger entry/Figure 6. “To verify a ledger value, a verifier verifies the Merkle signature on the provided message (P,T) using public key pk, and verifies that T corresponds to a set of posted value transactions” where T is set of transaction. Para. 0027, “T is the set of transactions or references to these”. Figure 6, ref. Transaction set 615 which is part of ledger entry 610; Transaction Set T 625 which also contains “event notification” is part of ledger entry 620… and Figure 6, ref. 610, 620, 630 and 640/ledger entry], the ledger entry Figure 6, ref. 610, 620, 630 and 640/ledger entry] comprising: a hash chain [Para. 0027, The ledger entry comprises values (leafi, pk1, pk2, P, i, sig1, sig2, T) where pk1 is the Merkle public key for the first Merkle signature sig1, pk2 is the Merkle public key for the second signature sig2, and T is the set of transactions or references to these. Para. 0026, Merkle signature using public key pk on the most recent set of transactions T…. Where “leafi/lowest level of the hash is computed as a hash h of (R, P, pk, i)” and I is leaf position. Sig 1= sig1 is a signature of portions of a previous ledger entry and commits the entire Merkle tree. Sig 2 also commits entire Merkle tree. Examiner Note: Leafi+ i+sig-+sig 2 they are hash chain component in the ledger entity. See for instance Para. Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 which is part of ledger entry such as Leafi+ i+sig-+sig 2 meets the limitation, “hash chain”]; and an event [Figure 6, ref. 625, Transaction set T which also contains “event notification” 626 which is part of the ledger entry 620, corresponds to the limitation “event”. Para. 0027, The ledger entry comprises values (leafi, pk1, pk2, P, i, sig1, sig2, T) where …T is the set of transactions or references. and Para. 0025 ,…T corresponds to a set of posted value transactions]
obtain a challenge using a cryptographic system [Para. 0024, “When a miner receives/obtains a challenge c”] wherein the challenge is based on the hash chain [See the following where challenge C is validated based on the leaves which is hash chain. Para. 0024, “When a miner receives a challenge c, it determines what leaf matches the challenge using a matching function. If a leaf value leafi matches c,” and para. 0026, “a leaf value leafi is computed as a hash h of (R, P, pk, i)”, and the leafi is part of the hash chain. See for instance Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 which is part of ledger entry such as Leafi+ i+sig-+sig 2 meets the limitation, “hash chain”] and the event [Para. 0025, a verifier verifies the Merkle signature on the provided message (P,T) using public key pk, and verifies that T corresponds to a set of posted value transactions. Figure 6, ref. 625, Transaction set T which also contains “event notification” 626 which is part of the ledger entry 620, corresponds to the limitation “event”. Para. 0027, The ledger entry comprises values (leafi, pk1, pk2, P, i, sig1, sig2, T) where …T is the set of transactions or references. and Para. 0025 ,…T corresponds to a set of posted value transactions];
Jakobsson doesn’t explicitly disclose the limitation, “broadcast a block that incorporates the ledger entry to securely add the block to a distributed ledger, wherein the block is capable of being validated by using a cryptographic system to obtain a proof based on the challenge”
However, Nakamoto explicitly discloses: broadcast a block that incorporates the ledger entry [Page 3, 5, 1-2. 1) New transactions are broadcast to all nodes. 2) Each node collects new transactions into a block] to securely add the block to a distributed ledger [Page 5, 8, “.. blocks added after it further confirm the network has accepted it” Page 3, 5. Network; 2-4, 3) 2) Each node collects new transactions into a block. Each node works on finding a difficult proof-of-work for its block. 4) When a node finds a proof-of-work, it broadcasts the block to all nodes. Examiner Note: In the Nakamoto paper, a block is added through a Proof-of-Work (PoW) competition where miners solve a hard math puzzle /challenge (finding a nonce) for a block of transactions; the winner broadcasts the solved block, other nodes verify the solution and transactions, then link it to the longest chain, reinforcing the network's distributed ledger and securing transactions through computational effort and economic incentives]
wherein the block is capable of being validated by using a cryptographic system to obtain a proof based on the challenge [Page 3, 4, “Proof-of-Work” and 5. Network, shows how miners are competing to solve and validate the challenge/Proof-of-work, “The proof-of-work involves scanning for a value that when hashed, such as with SHA-256, the hash begins with a number of zero bits” Note: this is the computational puzzle/challenge. Page 3. 5. “Network”, 3-5, 3) Each node works on finding a difficult proof-of-work for its block. 4) When a node finds a proof-of-work, it broadcasts the block to all nodes 5) Nodes accept the block only if all transactions in it are valid.”. Nodes always consider the longest chain to be the correct one and will keep working on extending it. Examiner Note: In the Nakamoto paper, a block is validated through a Proof-of-Work (PoW) consensus mechanism: nodes collect transactions, miners race to solve a difficult computational puzzle/corresponds to the claim limitation “challenge” (finding a nonce that produces a hash below a target), the first to solve it broadcasts the block, other nodes verify the block's validity (transactions are valid, not spent)]
Jakobsson and Nakamoto are an analogous in the same field of endeavor as they both address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson, a broadcasting and validation rules such as “broadcast a block that incorporates the ledger entry to securely add the block to a distributed ledger, wherein the block is capable of being validated by using a cryptographic system to obtain a proof based on the challenge” as per teaching of Nakamoto for enhancing the security of the system through a combination of decentralization, cryptography, and economic incentives. [Nakamoto, Abstract, The key security mechanisms are designed to allow a decentralized transactions between two parties without the need for a trusted third party like a bank..]
The following is referring to dependent claims 2-3:
As per dependent claim 2, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the proof is generated based on an iterative process [Para. 0023, “a miner selects one or more seed values, each represented by a value s, and then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function. In some embodiments, f is the function SHA256. As a result, an array of n leaves are generated, where n is preferably a power of two. From the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated”. Examiner Note: Hash tree in Merkle tree is iterative hashing each hash is computed in sequence/repeatedly, which corresponds to the claim limitation, “iterative process”]
As per dependent claim 3, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the challenge is further based on a hardness value [Abstract, the personalized challenge having an associated difficulty/hardness value determined based at least in part on a comparison of the designated amount of storage available for generating the proofs of space and a maximum amount of storage for a mining instance in the proof of space based mining system. Para, 0045, challenge may be a function of at least one of: the information associated with a mining instance, which is also referred to as the graph; the size of the graph; the Merkle tree associated with the graph, which is also referred to as a commitment to the graph; and a global difficulty parameter/hardness value that is used to control all personalized challenges at the same time. An example of the global difficulty parameter is an offset value that is used to modify the difficulty of all personalized challenges, e.g., by doubling their difficulty/hardness value, reducing their difficulty by 50%, etc.]
8. Claims 4-7 are rejected under 35 U.S.C. 103 as being unpatentable over Bjorn Markus Jakobsson (herein after referred as Jakobsson) (US Publication No. 2019/0324995 A1) (Published on Oct. 24, 2019) in view of NPL document, titled, “Bitcoin: A Peer-to-Peer Electronic Cash System” by Satoshi Nakamoto (2008) (herein after referred as Nakamoto) and further in view of Rahul Suraparaju (herein after referred as Suraparaju) (US Pub. No. 20190306190 A1) (Pub. Date: Oct. 3,2019).
As per dependent claim 4, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the challenge is further based on a hardness value [Abstract, the personalized challenge having an associated difficulty/hardness value determined based at least in part on a comparison of the designated amount of storage available for generating the proofs of space and a maximum amount of storage for a mining instance in the proof of space based mining system. Para, 0045, challenge may be a function of at least one of: the information associated with a mining instance, which is also referred to as the graph; the size of the graph; the Merkle tree associated with the graph, which is also referred to as a commitment to the graph; and a global difficulty parameter that is used to control all personalized challenges at the same time. An example of the global difficulty parameter is an offset value that is used to modify the difficulty of all personalized challenges, e.g., by doubling their difficulty/hardness value, reducing their difficulty by 50%, etc.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the hardness value is modified based on an occurrence of at least one collision associated with the event”
However, Suraparaju discloses: “wherein the hardness value is modified based on an occurrence of at least one collision associated with the event” [Abstract, “A modified mining algorithm of the conventional bitcoin system adopts, during some periods of time, a lower difficulty for proof-of-work (PoW) than the default difficulty of the conventional bitcoin system, while implementing a malicious fork detection mechanism to monitor the bitcoin blockchain during periods of reduced difficulty”.. “If a malicious fork is found, the mining difficulty is increased back to the default value for a period of time” Examiner Note: A malicious fork is a collision in the ledger (two conflicting branches) when such a collision is detected, the difficulty (hardness value) is increased back to default. This corresponds to “hardness value is modified based occurrence of at least one collision associated with the event”]
Jakobsson, Nakamoto and Suraparaju are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson and Nakamoto, a modification of hardness based on a fork/collision occurrence such as “the hardness value is modified based on an occurrence of at least one collision associated with the event” as per teaching of Suraparaju for enhancing the security of the system by greatly reducing the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain without limiting the capacity of the bitcoin blockchain [Suraparaju, para. 0005, This PoW scheme greatly reduces the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain. However, it also limits the capacity of the bitcoin blockchain (i.e. the amount of transaction data that can be recorded per unit time)]
As per dependent claim 5, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the challenge is based on a hardness value [[Abstract, the personalized challenge having an associated difficulty/hardness value determined based at least in part on a comparison of the designated amount of storage available for generating the proofs of space and a maximum amount of storage for a mining instance in the proof of space based mining system. Para, 0045, challenge may be a function of at least one of: the information associated with a mining instance, which is also referred to as the graph; the size of the graph; the Merkle tree associated with the graph, which is also referred to as a commitment to the graph; and a global difficulty parameter that is used to control all personalized challenges at the same time. An example of the global difficulty parameter is an offset value that is used to modify the difficulty of all personalized challenges, e.g., by doubling their difficulty/hardness value, reducing their difficulty by 50%, etc.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the challenge is further based on a hardness value and wherein the hardness value is modified based on a number of ledger closings”
However, Suraparaju explicitly discloses: “wherein a hardness value and wherein the hardness value is modified based on a number of ledger closings” [Para. 0010, (d) after adding a predefined number of blocks to the main blockchain, performing a malicious fork detection process. Abstract, “A modified mining algorithm of the conventional bitcoin system adopts, during some periods of time, a lower difficulty for proof-of-work (PoW) than the default difficulty of the conventional bitcoin system, while implementing a malicious fork detection mechanism to monitor the bitcoin blockchain during periods of reduced difficulty”.. “If a malicious fork is found, the mining difficulty is increased back to the default value for a period of time. The default difficulty corresponds to 2016 blocks every 14 days, while the reduced difficulty corresponds to 2016 blocks every 10 days.” Examiner Note: any operation that finalizes a group of transactions and commits to the ledger meets the limitation of ledger closings. In Surapaju, a block collects a set of transactions, after validation, the block is finalized and a predefined number of blocks are added to the chain. This is the same as closing a ledger. ]
Jakobsson, Nakamoto and Suraparaju are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson and Nakamoto, a modification of hardness based on completing of adding a predefined number of blocks into the ledger/block closure such as “wherein a hardness value and wherein the hardness value is modified based on a number of ledger closings” as per teaching of Suraparaju for enhancing the security of the system by greatly reducing the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data [Suraparaju, para. 0005, This PoW scheme greatly reduces the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain.]
As per dependent claim 6, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the challenge is based on a hardness value [Abstract, the personalized challenge having an associated difficulty/hardness value determined based at least in part on a comparison of the designated amount of storage available for generating the proofs of space and a maximum amount of storage for a mining instance in the proof of space based mining system. Para, 0045, challenge may be a function of at least one of: the information associated with a mining instance, which is also referred to as the graph; the size of the graph; the Merkle tree associated with the graph, which is also referred to as a commitment to the graph; and a global difficulty parameter that is used to control all personalized challenges at the same time. An example of the global difficulty parameter is an offset value that is used to modify the difficulty of all personalized challenges, e.g., by doubling their difficulty/hardness value, reducing their difficulty by 50%, etc.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the hardness value is modified based on a change in system time”
However, Suraparaju discloses: “wherein the hardness value is modified based on a change in system time” [Para.0004, s more miners join the bitcoin network and compete to generate valid blocks, the average time it takes for a valid block to be generated will decrease (i.e. the rate of block generation will increase). The bitcoin system is designed so that the difficulty target is adjusted every 2016 blocks, to a value such that the previous 2016 blocks would have been generated in 14 days (i.e. an average rate of approximately one block every 10 minutes) had every miner been mining at that difficulty/hardness. This keeps the average rate of block generation approximately constant (approximately one block every 10 minutes) over time. Claim 1. “for a predefined time period, performing mining operation using a default mining difficulty index to add blocks to the main blockchain, without performing the malicious fork detection process, the default mining difficulty index/hardness being more difficult than the reduced mining difficulty index. Examiner Note: Para. 0004 and abstract and claim 1, teaches difficulty/hardness value that changes to maintain a target time interval. If blocks are generated faster than expected, the difficulty increases, and if blocks are generated slower than expected, the difficulty decreases…A time interval measures the duration between two points in system time. Thus, this meets the limitation, “the hardness value is modified based on a change in system time’]
Jakobsson, Nakamoto and Suraparaju are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson and Nakamoto, a modification of hardness based on time interval or system clock such as “wherein the hardness value is modified based on a change in system time” as per teaching of Suraparaju for enhancing the security of the system by greatly reducing the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data [Suraparaju, para. 0005, This PoW scheme greatly reduces the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain.]
As per dependent claim 7, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses the device, wherein the challenge is based on a hardness value [Abstract, the personalized challenge having an associated difficulty/hardness value determined based at least in part on a comparison of the designated amount of storage available for generating the proofs of space and a maximum amount of storage for a mining instance in the proof of space based mining system. Para, 0045, challenge may be a function of at least one of: the information associated with a mining instance, which is also referred to as the graph; the size of the graph; the Merkle tree associated with the graph, which is also referred to as a commitment to the graph; and a global difficulty parameter that is used to control all personalized challenges at the same time. An example of the global difficulty parameter is an offset value that is used to modify the difficulty of all personalized challenges, e.g., by doubling their difficulty/hardness value, reducing their difficulty by 50%, etc.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the hardness value is modified based on an absence of at least one collision associated with the event”
However, Suraparaju explicitly discloses: “wherein the hardness value is modified based on an absence of at least one collision associated with the event” [Para.0010, (e) in response to no malicious fork being detected/no collision or absence of collision in the malicious fork detection process in step (d), repeating steps (c) c) performing mining operation using the reduced mining difficulty index/reducing the hardness value]
Jakobsson, Nakamoto and Suraparaju are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson and Nakamoto, a modification of hardness based on absence of collision such as “the hardness value is modified based on an absence of at least one collision associated with the event” as per teaching of Suraparaju for enhancing the security of the system by greatly reducing the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain [Suraparaju, para. 0005, This PoW scheme greatly reduces the probability of successful attacks on the blockchain, the attack being malicious miners attempting to generate valid blocks with fabricated transaction data and to have the malicious blocks being accepted as a part of the longest chain. However, it also limits the capacity of the bitcoin blockchain (i.e. the amount of transaction data that can be recorded per unit time)]
9. Claims 8-10 are rejected under 35 U.S.C. 103 as being unpatentable over Bjorn Markus Jakobsson (herein after referred as Jakobsson) (US Publication No. 2019/0324995 A1) (Published on Oct. 24, 2019) in view of NPL document, titled, “Bitcoin: A Peer-to-Peer Electronic Cash System” by Satoshi Nakamoto (2008) (herein after referred as Nakamoto) and further in view Anatoly Yakovenko (Yakovenko) (International application, Publication No. WO2019113495A1, Pub. Date: June 13, 2019.
The following is referring to independent claims 8-10:
As per dependent claim 8, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses “the hash chain” [Para. Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 meets the limitation, “hash chain”. Furthermore Nakamot on at least abstract teaches “hash chain”, “A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work”. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the hash chain is used for a Proof of History computation”
However, Yakovenko discloses: ” wherein the hash chain is used for a Proof of History computation” [Figure 10-12 and para. 0026-0027, [0026] Figure, ref. “Proof of History Hash” and Fig. 11 shows the system architecture showing the currently active Proof of History generator node and downstream nodes; [0027] Fig. 12 shows the Proof of History generator node of Fig. 11 with incoming and outgoing traffic; and Para. 0083, continuous chain of hashes 0006, Such a cryptographically secure function may be completely executed to generate an output, and such function may be run iteratively in a sequence so that its output from a previous execution may be used as the input in the current execution. The current output and/or how many times it has been executed or called can be periodically recorded].
Jakobsson, Nakamoto and Yakovenko are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entry system of Jakobsson and Nakamoto, a Proof of History computation such as “wherein the hash chain is used for a Proof of History computation” as per teaching of Yakovenko for enhancing the security of the system by disabling any misbehaving validators. [Yakovenko, para. 0092, a specific instance of proof of stake permits quick confirmation of the current sequence produced by a proof of history (PoH) generator, for voting and selecting the next proof of history generator, and for disabling any misbehaving validators. ]
As per dependent claim 9, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses “the hash chain” [Para. Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 meets the limitation, “hash chain”. Furthermore, Nakamot on at least abstract teaches “hash chain”, “A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work”. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power.]
The combination of Jakobsson and Nakamoto doesn’t explicitly discloses:
“wherein the hash chain is used to create a relative order between recorded events, wherein the recorded events comprise the event”
However, Yakovenko explicitly discloses: “wherein the hash chain is used to create a relative order between recorded events, wherein the recorded events comprise the event” [Para. 0006, A cryptographically secure hash function may be used herein whose output cannot be predicted from the input. Such a cryptographically secure function may be completely executed to generate an output, and such function may be run iteratively in a sequence so that its output from a previous execution may be used as the input in the current execution. The current output and/or how many times it has been executed or called can be periodically recorded. The output can then be recomputed and verified by external computers in parallel by checking one or more iterations in parallel on separate computer(s). Data can be timestamped into the sequence by recording the data and the index when the data is mixed into the sequence. Such timestamp then may guarantee that the data was created sometime before a next output of the secure function is generated in the sequence. Multiple clocks can synchronize amongst each other by mixing their state into each other’s sequences. Para. 0007, The present disclosure may advantageously enable creation of a temporal order of events that does not have to be trusted by any of the external clients. Note the sequence of hashes is the hash chain.]
Jakobsson, Nakamoto and Yakovenko are an analogous in the same field of endeavor as they all address data in distributed ledger using cryptographic proof.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to implement in the challenge-verified ledger entries system of Jakobsson and Nakamoto, sequence of recorded events such as “wherein the hash chain is used to create a relative order between recorded events, wherein the recorded events comprise the event” as per teaching of Yakovenko for enhancing the security of the system by disabling any misbehaving validators. [Yakovenko, para. 0092, a specific instance of proof of stake permits quick confirmation of the current sequence produced by a proof of history (PoH) generator, for voting and selecting the next proof of history generator, and for disabling any misbehaving validators]
10. As per dependent claim 10, the combination of Jakobsson and Nakamoto discloses the device as applied to claim 1 above. Furthermore, Jakobsson discloses “the hash chain” [Para. Para. 0023, a miner then computes a collection of leaves in a Merkle tree from s by applying a one-way function to s. For example, if the leaves are numbered 0 . . . n−1, the miner generates the jth Merkle leaf as f(s,j), where f is a one-way function such as a cryptographic hash function….., f is the function SHA256. As a result, an array of n leaves are generated, ”… the leaves, n internal node values are generated by applying, to each leaf, a one-way function such as a hash function h. These n internal nodes are then concatenated pairwise, resulting in n/2 pairs, where each such pair is then hashed, resulting in n/2 internal nodes on the next level. This is repeated until only one resulting value is generated, where this resulting value will represent all the n Merkle leaf values generated from s. The Merkle structure/tree that is produced by repeated hashing described in para. 0023-0024 meets the limitation, “hash chain”. Furthermore Nakamot on at least abstract teaches “hash chain”, “A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution. Digital signatures provide part of the solution, but the main benefits are lost if a trusted third party is still required to prevent double-spending. We propose a solution to the double-spending problem using a peer-to-peer network. The network timestamps transactions by hashing them into an ongoing chain of hash-based proof-of-work, forming a record that cannot be changed without redoing the proof-of-work”. The longest chain not only serves as proof of the sequence of events witnessed, but proof that it came from the largest pool of CPU power.] and wherein the challenge is computed by combining the hash chain with the event [para. 0025, “c is computed as the hash of a value” comprising “the concatenation of the most recent ledger entry. Para. 0044 further teaches that transaction information, “would contribute to the challenge”]
The combination of Jakobsson and Nakamoto doesn’t explicitly disclose the following underlined claim limitation:
“wherein the hash chain comprises a series of iteratively computed hash values where each hash value is computed using an output of a previous hash computation as input, and wherein the challenge is computed by combining the hash chain with the event to establish a temporal ordering of the event”
However, Yakovenko explicitly discloses:
“wherein the hash chain comprises a series of iteratively computed hash values where each hash value is computed using an output of a previous hash computation as input [Para. 0044, the preceding output is “passed as input into the same function again” para. 0046-0048 illustrate the sequential operations sha256(hashl) -> hash2 and sha256(hash2) -> hash3, and record the resulting values as a sequence. Note: Yakovenko expressly teaches the claimed linear iterative hash chain. Each newly generated hash is calculated using the output of the immediately preceding hash operation as the input to the next operation. Nakamoto independently reinforces this teaching by including the previous block hash in the calculation of the next block hash.], and wherein the challenge is computed by combining the hash chain with the event [Para. 0056 and 0058, and event hash is “appended to the binary data of the current hash” after which the next hash value is computed form the combined current hash and event hash. Para. 0043 and 0062 expressly identify the inserted data as a cryptographic hash value of an event]
to establish a temporal ordering of the event [Para. 0060, explains that sequential execution permits the order of entered events to be determined without an external clock. Para. 0063 teaches carrying the event insertion into the next hash values and para. 0074 expressly states that the sequence is used to “determine the temporal order of event data” Note: because the event is inserted at a particular point in the sequential hash chain and changes the next and subsequent hash values, its position relative to other events is cryptographically established. Yakovenko therefore expressly teaches the claimed result of establishing temporal ordering]
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the challenge-verified ledger entries system of Jakobsson and Nakamoto, iteratively computed hash values such as “wherein the hash chain comprises a series of iteratively computed hash values where each hash value is computed using an output of a previous hash computation as input, and wherein the challenge is computed by combining the hash chain with the event to establish a temporal ordering of the event” as per teaching of Yakovenko for enhancing the security of the system by bounding the challenge to both the prior ledger history and the current event, preventing undetected alteration or reordering of the event and providing a cryptographically verifiable relative event time [Yakovenko, para. 0092, a specific instance of proof of stake permits quick confirmation of the current sequence produced by a proof of history (PoH) generator, for voting and selecting the next proof of history generator, and for disabling any misbehaving validators]
Conclusion
11. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
A. US Publication No. No 20200044827A1 Snow discloses a Factom protocol cost effectively separates any blockchain (such as the Bitcoin blockchain) from any cryptocurrency (such as the Bitcoin cryptocurrency). The Factom protocol provides client-defined Chains of Entries, client-side validation of Entries, a distributed consensus algorithm for recording the Entries, and a blockchain anchoring approach for security.
B. US Patent No. 11218324 B2 Wentz et al discloses a system for authenticating a requesting device using verified evaluators includes an authenticating device. The authenticating device is designed and configured to receive at least a first digitally signed assertion from a requesting device, the at least a first digitally signed assertion linked to at least a verification datum, evaluate at least a second digitally signed assertion, signed by at least a cryptographic evaluator, conferring a credential to the requesting device, validate the credential, as a function of the at least a second digitally signed assertion, and authenticate the requesting device based on the credential.
C. US Publication No. 20210192520 A1 Patel et al discloses a ramework is provided for an automated and distributed system including onboarding to a network utilizing a digital ledger, payment processing and settlement, and a data marketplace in which users control access to their data. The ledger is stored within a distributed architecture. The ledger includes blocks, wherein a complete copy of the ledger is stored on one or more nodes, and the ledger is capable of verifying the blocks. A credential request is provided that includes information that when received at a first node can be used to perform a credential lookup. A verified, issued credential is received when the credential lookup is successful. The framework allows for generating a zero knowledge proof using the verified, issued credential and for providing the zero knowledge proof. When the zero knowledge proof is received at a second node, the zero knowledge proof can be used to verify a criteria.
D. See the other cited prior arts.
12. 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 extension fee 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SAMSON B LEMMA whose telephone number is 571-272-3806. The examiner can normally be reached on M-F 8am-10pm.
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/SAMSON B LEMMA/Primary Examiner, Art Unit 2498
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