TWC: Small: On the Design of Secure Hash Functions and Block Ciphers

这个项目重新审视了构建安全哈希函数、分组密码和各种重要的加密原语的基本设计原则，通过研究基于更坚实的理论基础的新类型的结构，但仍然足够有效地用于实际使用。特别是，该项目侧重于分析和改进哈希函数和块密码作为消息摘要、密钥派生函数、消息认证码、流密码、承诺方案和随机预言机的使用。此外，研究人员还研究了新的操作模式，以从更简单的固定长度组件（如分组密码和固定长度压缩函数）构建复杂的变长原语。该项目还研究了可证明的加密算法和标准免受潜在未知后门攻击的可行性。最后，该项目为分析理想安全模型中的密码方案（如随机oracle和理想密码模型）奠定了坚实的基础。该项目旨在产生更安全的哈希函数和分组密码，以及在重要的密码学应用中更安全和/或更有效地使用哈希函数和分组密码。除了推进密码学理论之外，该项目还通过建议在此类应用中更合理地使用各种加密构建块，影响了安全系统的实际设计。PI定期教授密码学和网络安全课程，并积极将新成果纳入他所教授的课程中。此外，该提案有一个重要的研究生和博士后培训的组成部分。

This project revisits the basic design principle for constructing secure hash functions, block ciphers, and various important cryptographic primitives which are built from them, by investigating new types of constructions that are based on firmer theoretical foundations, and yet are still efficient enough for practical use. In particular, the project focuses on analyzing and improving the use of hash functions and block ciphers as message digests, key derivation functions, message authentication codes, stream ciphers, commitment schemes and random oracles. Additionally, the investigators study novel modes of operation to build complex variable-length primitives from simpler, fixed length components, such as block ciphers and fixed-length compression functions. The project also examines the feasibility of provably immunizing cryptographic algorithms and standards against potentially unknown backdoors. Finally, the project builds firmer foundations for analyzing cryptographic schemes in the idealized security models, such as the random oracle and the ideal cipher models. The project aims to yield more secure hash functions and block ciphers, and more secure and/or efficient usage of hash functions and block ciphers in important cryptographic applications. Besides advancing the theory of cryptography, this project also impacts the real-world design of secure systems, by suggesting more sound use of various cryptographic building blocks for such applications. The PI regularly teaches courses in cryptography and network security, and is actively incorporating the new results into the courses he teaches. In addition, the proposal has a significant graduate student and postdoc training component.