Open research questions in Cryptography and Data Security
108 unresolved questions extracted from the limitations and future-work sections of 395 Cryptography and Data Security papers in our library. Each links back to the study that raised it.
What the literature leaves open
The accuracy cost introduced by the encryption overhead, specifically the combined effect of polynomial activation approximation error, ciphertext rounding noise, and modulus switching precision loss. The need for privacy-guaranteeing mechanisms in cloud-based ML pipelines. The requirement for encrypted computation in cross-institutional financial intelligence sharing.
HE-CloudML: a privacy-preserving framework for secure machine learning inference over encrypted cloud data using homomorphic encryption · 2026 · DOIInvestigating resistance to active/malicious-server, model-inversion, or membership-inference attacks - Evaluating HE-CloudML on more real-world sensitive domains - Exploring the application of HE-CloudML to other machine learning tasks
HE-CloudML: a privacy-preserving framework for secure machine learning inference over encrypted cloud data using homomorphic encryption · 2026 · DOIA major limitation of existing FHE frameworks is their inefficiency in evaluating nonlinear operations, which incur substantial overhead and dominate the decode stage.
ROSETTA: Efficient and Accurate Privacy-Preserving LLM Decoding via Hybrid CKKS/TFHE Evaluation · 2026Experimental evaluation of DMBB-RCB to validate its performance in practice. Investigation of the scheme's security against unknown lattice attacks. Development of methods to reduce the memory consumption of DMBB-RCB. Exploration of the scheme's applications in other domains, such as secure genome analysis or financial auditing.
The current MK-FHE solutions have linear computational growth and low bootstrapping throughput. The existing dynamic MKHE solutions suffer from severe network latency due to interactive multi-party key-switching after each bootstrapping. There is a need for a scheme that supports the dynamic addition of participants without parameter re-generation and enables depth-unbounded homomorphic evaluations with zero interaction between participants during the computation phase.
The existing searchable encryption schemes suffer from inefficient index construction and search process. The lack of support for dynamic updates and concealment of access patterns.
The lack of efficient and scalable solutions for searching encrypted data in cloud computing. The need for a secure and privacy-preserving data retrieval scheme that addresses the security and privacy concerns related to data confidentiality, unauthorized access, and privacy preservation.
The experimental evaluation lacks testing on realistic large-scale cloud datasets with millions of documents and dynamic insertion/deletion operations; scalability of the key-aggregate mechanism and optimized indexing to production-scale encrypted cloud environments remains unvalidated.
The paper identifies a research gap in the optimization of bootstrapping algorithms for FHE. The survey highlights the need for further research in reducing latency, enhancing parallelism, and controlling noise growth.
Future research can focus on optimizing the performance of DSKAG-IT-SIG. Future research can also explore the application of DSKAG-IT-SIG in other domains, such as secure multi-party computation.
DSKAG-IT-SIG: Information-Theoretic Transaction Signatures with Hardware-Bound Policy Binding and Permissionless Zero-Knowledge On-Chain Verification · 2026 · DOIThe blockchain and tokenized real-world asset industries face a structural cryptographic problem with current transaction signature schemes. Existing schemes are simultaneously too large, computationally secure rather than unconditionally secure, and architecturally disconnected from the compliance policy layer.
DSKAG-IT-SIG: Information-Theoretic Transaction Signatures with Hardware-Bound Policy Binding and Permissionless Zero-Knowledge On-Chain Verification · 2026 · DOIExisting schemes neither support the dynamic granting and revocation of users nor enable users to control the release of their attributes. There is a need for a lattice-based dynamic k-TAA scheme with attribute-based credentials.
Lattice-based dynamic k -times anonymous authentication with attribute-based credentials · 2026 · DOIThe lack of a secure and efficient broadcast encryption scheme that can prevent malicious encryptors and data leakage. The need for a public tracing mechanism to identify colluding malicious users. The requirement for a smart contract system to implement authentication services and store relevant data.
Traceable and Revocable Broadcast Encryption Scheme for Preventing Malicious Encryptors · 2026 · DOIThe lack of robustness in managing irrational updates in existing encrypted spatial-textual data retrieval schemes. The need for a novel scheme that achieves forward security, Type-I backward security, and enhanced robustness for boolean range queries.
REACTS: robust encrypted search for dynamic spatial-textual data with permission control · 2026 · DOITo bound the multi-target IND-CPA security of existing PKEs which underlie prominent KEMs such as HQC, FrodoKEM, and ML-KEM. To analyze the security of other KEMs using the SFO transform.
The standard IND-CCA security definition for KEMs considers only a single challenge public key and single challenge ciphertext, which may not be sufficient for practical deployments. There is a lack of proof showing that salting provides multi-ciphertext security.
To further improve the efficiency of the algorithm. To apply the algorithm to other problems in differential privacy. To explore the applications of the algorithm in practice.
The previous best deterministic-time bound for releasing differentially private sparse histograms was Õ(n^2). There was a need for an algorithm that achieves the optimal ℓ ∞-estimation error and runs in strictly O(n) time.
Bidirectional authorization raises concerns - Existing ORE schemes have limitations
To further develop the DEF-CRYPT-Q framework for practical implementation. To explore the application of DEF-CRYPT-Q in other domains.
DEF-CRYPT-Q: a quantum-enhanced hybrid encryption framework for privacy-preserving distributed defense communications · 2026 · DOIExisting cryptographic infrastructures are not suitable for heterogeneous defense settings. Traditional public-key algorithms are vulnerable to quantum attacks.
DEF-CRYPT-Q: a quantum-enhanced hybrid encryption framework for privacy-preserving distributed defense communications · 2026 · DOIThe advent of quantum computing poses a severe danger to the encryption techniques used to safeguard electronic health records. There is a need for a robust security system that can protect electronic health records against quantum attacks.
<p>Enhancing Blockchain Security for Electronic Health Records with Hybrid Encryption and Anti-Quantum Signatures</p> · 2026 · DOIAlthough the hybrid signature system that combines Dilithium and ECDSA seem promising, further investigation into How to cite this article: Bhabad H P, Rajawat A (May 22, 2026) Enhancing Blockchain Security for Electronic Health Records with Hybrid Encryption and Anti-Quantum Signatures.
<p>Enhancing Blockchain Security for Electronic Health Records with Hybrid Encryption and Anti-Quantum Signatures</p> · 2026 · DOIThe interplay between quantum computing and federated learning poses a challenge to conventional cryptographic authentication protocols. Traditional public key systems become inefficient due to Shor’s algorithm.
Third, Future research should focus on (1) reducing the proof size of Zero-Knowledge proofs for deep neural networks, (2) integrating hardware security modules (HSMs) optimized for lattice-based cryptography to accelerate edge authentication, and (3) developing migration strategies for legacy IoT devices that lack the computational resources for ML-DSA, potentially relying on hybrid mode where gateways perform the heavy lifting.
Most-cited papers in Cryptography and Data Security
- How to share a secret · Communications of the ACM · 1979 · 10,601 citations
- Untraceable electronic mail, return addresses, and digital pseudonyms · Communications of the ACM · 1981 · 2,977 citations
- A survey of trust and reputation systems for online service provision · Decision Support Systems · 2005 · 2,428 citations
- Computing arbitrary functions of encrypted data · Communications of the ACM · 2010 · 468 citations
- Secure attribute-based data sharing for resource-limited users in cloud computing · Computers & Security · 2017 · 403 citations
- Privacy-Preserving Machine Learning With Fully Homomorphic Encryption for Deep Neural Network · IEEE Access · 2022 · 376 citations
- A method for obtaining digital signatures and public-key cryptosystems · Communications of the ACM · 1983 · 346 citations
- Pinocchio · Communications of the ACM · 2016 · 197 citations
- Hierarchical attribute-based encryption and scalable user revocation for sharing data in cloud servers · Computers & Security · 2011 · 185 citations
- Privacy integrated queries · Communications of the ACM · 2010 · 174 citations
Most recent work
- Homomorphic encryption for secure healthcare artificial intelligence · Discover Artificial Intelligence · 2026
- PCL-BPRE: privacy-preserving certificateless-based broadcast proxy re-encryption for data sharing in cloud-based IIoT · Future Generation Computer Systems · 2026
- On The Multi-target Security of Post-Quantum Key Encapsulation Mechanisms · IACR Communications in Cryptology · 2026
- Identity Crisis in Confidential Computing: Formal Analysis of Attested TLS · 2026
- Homomorphic Encryption in Finance: Training and Inference on Encrypted Data with Concrete ML · Afyon Kocatepe University Journal of Sciences and Engineering · 2026
- Protecting HWSNs from Super Adversaries with Robust Certificateless Signcryption · Telecom · 2026
- Authenticated encryption from packed secret sharing: Scalable one-pass lightweight design with provable security · Journal of Information Security and Applications · 2026
- Efficient Batched IBE from Lattices in the Standard Model · IACR Communications in Cryptology · 2026
- Merits of geometric algebra applied to cryptography and machine learning · Philosophical Transactions of the Royal Society A Mathematical Physical and Engineering Sciences · 2026
- A Blockchain-Assisted Quantum Encryption Scheme for Secure Communication in Internet of Things Networks · IEEE Internet of Things Magazine · 2026
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