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Ren Guo

Publications and source records attributed to Ren Guo.

At least 19 recordsLinked to original sources
arXiv2025

Cryptographic Application of Elliptic Curve with High Rank

Elliptic curve cryptography is better than traditional cryptography based on RSA and discrete logarithm of finite field in terms of efficiency and security. In this paper, we show how to exploit elliptic curve with high rank, which has not been used in cryptography before, to construct cryptographic schemes. Concretely we demonstrate how to construct public key signature scheme with hierarchy revocation based on elliptic curve with high rank, where the rank determines the height of the revocation tree. Although our construction is not very efficient in some sense, our construction shows elliptic curve with high rank is valuable and important for cryptographic usage. The technique and assumption presented can surely be used for other cryptographic constructions.

cs.CR↗
arXiv2025

Huawei Cloud Model-as-a-Service on the CloudMatrix384 SuperPod

Scaled-out MoE LLMs and scaled-up SuperPods create new systems challenges for production Model-as-a-Service (MaaS), requiring disaggregation, low-latency communication, and decentralized serving. This report presents xDeepServe, the production serving system behind Huawei Cloud's MaaS offering on CloudMatrix384, a 48-server SuperPod with 384 Ascend 910C chips connected by a high-bandwidth UB fabric and global shared memory. It serves models including DeepSeek, Kimi, GLM, Qwen, and MiniMax, among others. xDeepServe is built around Transformerless, a disaggregated execution architecture that decomposes transformer inference into modular units -- attention, feedforward, and MoE -- and supports disaggregated Prefill-Decode and MoE-Attention deployments. To enable disaggregation, we develop XCCL, a memory-semantic communication layer providing microsecond-level point-to-point and scalable all-to-all primitives, and we extend FlowServe with decentralized DP groups and techniques to mitigate stragglers and synchronization variance. In a peak decoding configuration, xDeepServe reaches 2400 tokens/s per Ascend 910C chip at ~50ms time-per-output-token (TPOT).

cs.DC↗
arXiv2025

Enhanced Security of Public Key Encryption with Certified Deletion

In classical cryptography, certified deletion is simply impossible. Since classical information can be copied any number of times easily. In quantum cryptography, certified deletion is possible because of theorems of quantum mechanics such as the quantum no-clone theorem, quantum superposition etc. In this paper, we show the PKE-CD (Public Key Encryption with Certified Deletion) scheme constructed in by Bartusek and Khurana in CRYPTO 2023 lack an important security property, which is important in practical applications. Then we show how to enhance this property, and construct a concrete scheme with this property. And we also discuss the relations between PKE-CD and other quantum cryptographic schemes such as quantum seal, quantum bit commitment etc.

cs.CR↗
arXiv2024

Research on Data Right Confirmation Mechanism of Federated Learning based on Blockchain

Federated learning can solve the privacy protection problem in distributed data mining and machine learning, and how to protect the ownership, use and income rights of all parties involved in federated learning is an important issue. This paper proposes a federated learning data ownership confirmation mechanism based on blockchain and smart contract, which uses decentralized blockchain technology to save the contribution of each participant on the blockchain, and distributes the benefits of federated learning results through the blockchain. In the local simulation environment of the blockchain, the relevant smart contracts and data structures are simulated and implemented, and the feasibility of the scheme is preliminarily demonstrated.

cs.CR↗
arXiv2024

Collaboration Encouraging Quantum Secret Sharing Scheme with Seal Property

A new concept of quantum secret sharing is introduced, in which collaboration among participants are encourage. And the dealer can ask the participants to send back their share and revoke the secret before a predefined date or event, i.e. so-called seal property. We also give two concrete constructions of CE-QSS-Seal (Collaboration-Encouraging Quantum Secret Sharing with Seal property) scheme. The first one is unconditional secure and achieve the optimal bound of a seal scheme. The second one improve the optimal bound of seal by introducing post-quantum secure computational assumption.

quant-ph↗
arXiv2023

Concept and Construction of Group Signature with self-proof capacity for confirming and denying

With privacy-preserving and traceability properties, group signature is a cryptosystem with central role in cryptography. And there are lots of application scenarios. A new extension concept of group signature is presented, namely group signature with self-proof capacity. For a legitimate group signature, the real signer can prove that the signature is indeed signed by him/her. While for the other members of the group, they can prove that the signature is not signed by him/her. The former can be used for claiming money reward from the police, while the latter can be used for proving one's innocent in a criminal investigation.

cs.CR↗
arXiv2023

Better Quantum Seal Schemes based on Trapdoor Claw-Free Functions

Seal in classical information is simply impossible. Since classical information can be easily copied any number of times. Based on quantum information, esp. quantum unclonable theorem, quantum seal maybe constructed perfectly. But it is shown that perfect quantum seal is impossible, and the success probability is bounded. In this paper, we show how to exceed the optimal bound by using the TCF (Trapdoor Claw Free) functions, which can be constructed based on LWE assumption. Hence it is post-quantum secure.

quant-ph↗
arXiv2022

Quantum Advantage of Threshold Changeable Secret Sharing Scheme

In TCSS (Threshold Changeable Secret Sharing) scheme, the threshold can be changed to deal with share leakage in the long term. But in classical TCSS, there is no guarantee that old shares are deleted even if the participated parties are honest. So, the changed threshold may not prevent an adversary from reconstructing the secret by the old shares and old threshold number of parties. We show how to tackle this problem quantum mechanically. I.e., quantum mechanically we can make the changed threshold mandatory. So, there is quantum advantage of quantum TCSS over classical TCSS.

quant-ph↗
arXiv2017

Strengthened Euler's Inequality in Spherical and Hyperbolic Geometries

Euler's inequality is a well known inequality relating the inradius and circumradius of a triangle. In Euclidean geometry, this inequality takes the form $R \geq 2r$ where $R$ is the circumradius and $r$ is the inradius. In spherical geometry, the inequality takes the form $\tan(R) \geq 2\tan(r)$ as proved in \cite{MPV}; similary, we have $\tanh(R) \geq 2\tanh(r)$ for hyperbolic triangles (see \cite{SV} for proof). In Euclidean geometry, this inequality can be strengthened as discussed in \cite{SV}. We prove an analogous version of this strengthened inequality which holds in spherical geometry, as well as an additional strengthening of Euler's inequality which holds in Euclidean geometry and can be generalized into both spherical and hyperbolic geometry.

math.MG↗
arXiv2014

The Unified Surface Ricci Flow

Ricci flow deforms the Riemannian metric proportionally to the curvature, such that the curvature evolves according to a heat diffusion process and eventually becomes constant everywhere. Ricci flow has demonstrated its great potential by solving various problems in many fields, which can be hardly handled by alternative methods so far. This work introduces the unified theoretic framework for discrete Surface Ricci Flow, including all common schemes: Thurston's Circle Packing, Tangential Circle Packing, Inversive Distance Circle Packing and Discrete Yamabe. Furthermore, this work also introduces a novel scheme, virtual radius circle packing, under the unified framework. This work gives explicit geometric interpretation to the discrete Ricci energy for all the schemes, and Hessian of the discrete Ricci energy for schemes with Euclidean back ground geometry. The unified frame work deepen our understanding to the the discrete surface Ricci flow theory, and inspired us to discover the new schemes, improved the flexibility and robustness of the algorithms, greatly simplified the implementation and improved the debugging efficiency. Experimental results shows the unified surface Ricci flow algorithms can handle general surfaces with different topologies, and is robust to meshes with different qualities, and effective for solving real problems.

math.GT↗
arXiv2014

A discrete uniformization theorem for polyhedral surfaces II

A discrete conformality for hyperbolic polyhedral surfaces is introduced in this paper. This discrete conformality is shown to be computable. It is proved that each hyperbolic polyhedral metric on a closed surface is discrete conformal to a unique hyperbolic polyhedral metric with a given discrete curvature satisfying Gauss-Bonnet formula. Furthermore, the hyperbolic polyhedral metric with given curvature can be obtained using a discrete Yamabe flow with surgery. In particular, each hyperbolic polyhedral metric on a closed surface with negative Euler characteristic is discrete conformal to a unique hyperbolic metric.

math.GT↗
arXiv2011

Extremum problems for eigenvalues of discrete Laplace operators

The discrete Laplace operator on a triangulated polyhedral surface is related to geometric properties of the surface. This paper studies extremum problems for eigenvalues of the discrete Laplace operators. Among all triangles, an equilateral triangle has the maximal first positive eigenvalue. Among all cyclic quadrilateral, a square has the maximal first positive eigenvalue. Among all cyclic $n$-gons, a regular one has the minimal value of the sum of all nontrivial eigenvalues and the minimal value of the product of all nontrivial eigenvalues.

math.MG↗
arXiv2010

Discrete Laplace-Beltrami Operator Determines Discrete Riemannian Metric

The Laplace-Beltrami operator of a smooth Riemannian manifold is determined by the Riemannian metric. Conversely, the heat kernel constructed from its eigenvalues and eigenfunctions determines the Riemannian metric. This work proves the analogy on Euclidean polyhedral surfaces (triangle meshes), that the discrete Laplace-Beltrami operator and the discrete Riemannian metric (unique up to a scaling) are mutually determined by each other. Given an Euclidean polyhedral surface, its Riemannian metric is represented as edge lengths, satisfying triangle inequalities on all faces. The Laplace-Beltrami operator is formulated using the cotangent formula, where the edge weight is defined as the sum of the cotangent of angles against the edge. We prove that the edge lengths can be determined by the edge weights unique up to a scaling using the variational approach. First, we show that the space of all possible metrics of a polyhedral surface is convex. Then, we construct a special energy defined on the metric space, such that the gradient of the energy equals to the edge weights. Third, we show the Hessian matrix of the energy is positive definite, restricted on the tangent space of the metric space, therefore the energy is convex. Finally, by the fact that the parameter on a convex domain and the gradient of a convex function defined on the domain have one-to-one correspondence, we show the edge weights determines the polyhedral metric unique up to a scaling. The constructive proof leads to a computational algorithm that finds the unique metric on a topological triangle mesh from a discrete Laplace-Beltrami operator matrix.

cs.DM↗
arXiv2010

Cyclic polygons in classical geometry

Formulas about the side lengths, diagonal lengths or radius of the circumcircle of a cyclic polygon in Euclidean geometry, hyperbolic geometry or spherical geometry can be unified.

math.MG↗
arXiv2010

Calculus of generalized hyperbolic tetrahedron

We calculate the Jacobian matrix of the dihedral angles of a generalized hyperbolic tetrahedron as functions of edge lengths and find the complete set of symmetries of this matrix.

math.MG↗
arXiv2010

Cell decompositions of Teichmüller spaces of surfaces with boundary

A family of coordinates $ψ_h$ for the Teichmüller space of a compact surface with boundary was introduced in \cite{l2}. In the work \cite{m1}, Mondello showed that the coordinate $ψ_0$ can be used to produce a natural cell decomposition of the Teichmüller space invariant under the action of the mapping class group. In this paper, we show that the similar result also works for all other coordinate $ψ_h$ for any $h \geq 0$.

math.GT↗
arXiv2010

Curvatures on the Teichmüller curve

The Teichmüller curve is the fiber space over Teichmüller space of closed Riemann surfaces, where the fiber over a point in Teichmüller space is the underlying surface. We derive formulas for sectional curvatures on the Teichmüller curve. In particular, our method can be applied to investigate the geometry of the Weil-Petersson geodesic as a three-manifold, and the degeneration of the curvatures near the infinity of the augmented Teichmüller space along a Weil-Petersson geodesic, as well as the minimality of hyperbolic surfaces in this three-manifold.

math.DG↗