{"id":"e767cacd-3998-42f6-a596-02aefc7ce7e0","arxiv_id":"2606.30407","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":3.0,"correctness_risk":"unknown","formal_verification":"none","parameter_count":0,"one_line_summary":"Investigation of linear and lattice-reduction-aided preprocessing variants for secrecy in THz-MIMO, optimized on error performance or rate and evaluated by simulation.","lead":"The paper examines preprocessing methods to improve physical-layer security in THz-MIMO wireless links by optimizing either error rates or achievable rates, with options that ignore or account for an eavesdropper. A smart generalist might read it to see how standard signal-processing tools can be tuned for secure high-frequency communications without extra encryption layers.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.3","headline":"Simulations rely on idealized THz channel models without hardware impairments or imperfect CSI, which may not support the reliability+secrecy claim in deployment.","rationale":"The reader's weakest assumption directly identifies the simulation-to-reality gap as load-bearing; my analysis confirms it is the single point where the numerical evidence could fail to support the claim, with no other internal inconsistency visible from the given abstract and claim description.","tokens_in":1606,"tokens_out":316,"duration_ms":26911,"concrete_test":"Re-run the paper's secrecy-rate simulations (both linear and LR-aided cases) after adding (i) additive phase-noise variance of 0.05 rad and (ii) MMSE channel estimation error with variance 0.1; if any variant's secrecy rate falls below 0.5 bits/use or error ratio exceeds 10^-3 at the operating SNR, the headline claim does not survive the impairment model.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim is that linear/LR-aided preprocessing variants (optimized on error or rate, with/without Eve) achieve reliable+secure THz-MIMO communication, as shown by simulated secrecy rates and error ratios. This holds only if the underlying channel model and perfect-CSI assumption accurately reflect real THz propagation (directional beams, molecular absorption, phase noise, estimation errors). The abstract and simulations provide no analytical guarantee or sensitivity analysis; if the model mismatches, the reported positive secrecy rates and low error ratios can vanish while the optimization still runs.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The manuscript investigates preprocessing techniques to achieve physical-layer security in a THz-MIMO wireless scenario. The goal is reliable and secure communication via optimization of preprocessing based on either error performance or transmission rate. Variants are considered that account only for the legitimate receiver or also include the eavesdropper; for each, both linear and lattice-reduction-aided approaches are examined. Performance is evaluated exclusively through numerical simulations of secrecy rates and error ratios, followed by comparisons and discussion of trade-offs.","tokens_in":1719,"tokens_out":338,"duration_ms":31807,"significance":"If the simulation results prove robust, the work offers practical comparisons of preprocessing variants for PLS in THz systems, an area of growing interest due to high-frequency propagation challenges. The explicit inclusion of both error- and rate-based criteria, with and without eavesdropper knowledge, provides useful design insights. No machine-checked proofs, parameter-free derivations, or reproducible code are present, so the significance remains tied to the validity of the underlying simulation assumptions.","major_comments":[{"comment":"Abstract (and implied simulation sections): the central claim that the listed preprocessing variants achieve reliable+secure communication rests on unspecified channel models and a perfect-CSI assumption; this is load-bearing because, as noted in the stress-test, mismatch with real THz effects (molecular absorption, phase noise, estimation errors) can nullify the reported positive secrecy rates while the optimization still executes.","section":"Abstract"},{"comment":"Numerical simulations (throughout): no sensitivity analysis or discussion of hardware impairments is provided, so the reported secrecy-rate and error-ratio improvements cannot be assessed for stability under the imperfect-CSI conditions that the weakest-assumption note identifies as critical.","section":"Numerical simulations"}],"minor_comments":[],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for the constructive feedback highlighting the importance of clearly stating modeling assumptions. We address the two major comments below and will revise the manuscript to improve clarity on the idealized conditions used.","responses":[{"response":"The full manuscript specifies a standard THz-MIMO channel model (including molecular absorption) in the system model section, with all results derived under the perfect-CSI assumption at the transmitter. The reported secrecy rates and error ratios hold only under these conditions, which is standard for initial studies of preprocessing techniques. We will revise the abstract to explicitly state the perfect-CSI assumption and add a clarifying sentence in the introduction noting that real-world effects such as phase noise or CSI mismatch are outside the current scope.","revision_made":"yes","referee_comment":"[Abstract] Abstract (and implied simulation sections): the central claim that the listed preprocessing variants achieve reliable+secure communication rests on unspecified channel models and a perfect-CSI assumption; this is load-bearing because, as noted in the stress-test, mismatch with real THz effects (molecular absorption, phase noise, estimation errors) can nullify the reported positive secrecy rates while the optimization still executes."},{"response":"We agree a discussion of robustness would be beneficial. The paper's focus is the comparison of linear and lattice-reduction-aided preprocessing under ideal conditions; a full sensitivity analysis with hardware impairments would require substantial additional simulation campaigns beyond the present scope. We will add a dedicated paragraph in the numerical results section discussing the impact of potential impairments (e.g., estimation errors) as a limitation and direction for future work.","revision_made":"partial","referee_comment":"[Numerical simulations] Numerical simulations (throughout): no sensitivity analysis or discussion of hardware impairments is provided, so the reported secrecy-rate and error-ratio improvements cannot be assessed for stability under the imperfect-CSI conditions that the weakest-assumption note identifies as critical."}],"tokens_in":1230,"tokens_out":412,"duration_ms":44016,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The paper runs a comparison of preprocessing variants for physical-layer security in THz MIMO. They optimize either for error performance or transmission rate, include or exclude the eavesdropper in the design, and test both plain linear and lattice-reduction-aided versions. Numerical results on secrecy rates and error ratios are used to discuss the resulting trade-offs.\n\nWhat is actually new is the application and side-by-side evaluation in the THz setting, where high directionality and molecular absorption change the propagation picture. The simulations appear to show that accounting for the eavesdropper improves security metrics with limited reliability cost under the chosen models.\n\nThe soft spot is the complete dependence on idealized channel assumptions and perfect CSI. No hardware impairments, phase noise, or estimation errors are modeled, and there is no sensitivity check. If those factors matter in practice, the reported positive secrecy rates and low error ratios can disappear while the optimization still runs. The work contains no analytical guarantees or closed-form results, only the numerical comparison.\n\nThis is useful for researchers already working on THz communications or high-frequency PLS implementations. A reader looking for new theoretical tools or robust design methods will not find them here. The paper is coherent on its own terms and shows clear engagement with the standard PLS literature.\n\nI would send it to peer review. The comparison is concrete and the topic is current, even though the contribution is incremental and the modeling limitations should be addressed in revision.","headline":"This applies standard linear and LR-aided PLS preprocessing to THz-MIMO, compares error-rate and rate-based optimizations with and without the eavesdropper, and reports simulation trade-offs, but rests entirely on idealized channels.","tokens_in":2208,"tokens_out":374,"would_cite":false,"duration_ms":40313,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"Optimizing preprocessing in THz-MIMO systems can achieve both reliable communication for the intended receiver and security against eavesdroppers.","keywords":["physical-layer security","THz communication","MIMO","preprocessing","secrecy rate","lattice reduction","error performance","wireless security"],"falsifier":"A real THz-MIMO hardware test showing secrecy rates well below the simulated values when hardware impairments or channel estimation errors are present would falsify the claim that the optimized preprocessing delivers the reported security and reliability.","tokens_in":2494,"feed_emoji":"📡","tokens_out":605,"duration_ms":50779,"temperature":0.7,"pith_summary":"The paper examines preprocessing at the transmitter to support physical-layer security in wireless THz multiple-input multiple-output links. It compares optimization criteria based on error performance versus transmission rate, with versions that use only the legitimate receiver's channel and versions that also incorporate the eavesdropper. For each criterion, both standard linear preprocessing and lattice-reduction-aided versions are evaluated through numerical simulations that track secrecy rates and error ratios. A reader would care because THz bands offer high data rates for future wireless systems but need built-in ways to limit information leakage without extra cryptographic overhead.","feed_headline":"Preprocessing optimization secures THz-MIMO links in simulations","feed_subtitle":"Variants that balance receiver error and secrecy rates deliver both reliability and security over THz channels.","key_machinery":"The preprocessing matrix at the transmitter, optimized under error or rate criteria and with or without eavesdropper information, using either linear or lattice-reduction-aided designs.","core_discovery":"Optimization of the preprocessing matrix, performed either to improve error performance or transmission rate and either with or without the eavesdropper channel, yields positive secrecy rates together with acceptable error ratios at the legitimate receiver when linear or lattice-reduction-aided designs are applied in the THz-MIMO setting.","pith_inferences":["The same preprocessing approach could be tested in other high-frequency bands if similar channel statistics apply.","Adding explicit modeling of hardware impairments would show how much the simulated gains shrink in practice.","Combining the preprocessing with power allocation or antenna selection might further raise the secrecy rates."],"forward_implications":["Including the eavesdropper channel in the optimization improves the achieved secrecy rate compared with receiver-only designs.","Lattice-reduction-aided preprocessing produces lower error ratios than linear preprocessing under the same optimization criterion.","Optimizing for error performance tends to favor reliability while optimizing for rate tends to favor secrecy in the simulated scenarios.","All variants produce positive secrecy rates in the considered THz-MIMO channel models."],"fun_headline_variants":["THz-MIMO preprocessing for physical-layer security optimization","Preprocessing variants for THz-MIMO error and secrecy rates","THz-MIMO security via receiver or eavesdropper preprocessing","Linear and lattice preprocessing for THz security in MIMO"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"The simulated channel models and optimization criteria accurately capture the security-performance trade-offs that would occur in a real THz deployment with hardware impairments and imperfect channel knowledge.","fun_headline_variants_meta":{"raw":{"variants":["THz-MIMO preprocessing for physical-layer security optimization","Preprocessing variants for THz-MIMO error and secrecy rates","THz-MIMO security via receiver or eavesdropper preprocessing","Linear and lattice preprocessing for THz security in MIMO"]},"model":"grok-4.3","cost_usd":0.007157,"raw_usage":{"total_tokens":3225,"prompt_tokens":509,"num_sources_used":0,"completion_tokens":62,"cost_in_usd_ticks":71574500,"prompt_tokens_details":{"text_tokens":509,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":2654,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":509,"tokens_out":62,"duration_ms":46330,"temperature":1.0,"reasoning_tokens":2654,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-30T03:30:52.763356+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A real THz-MIMO hardware test showing secrecy rates well below the simulated values when hardware impairments or channel estimation errors are present would falsify the claim that the optimized preprocessing delivers the reported security and reliability.","supporting_citations":[],"review_version":1}