SaTC: CORE: Medium: Collaborative: New Frontiers in Encryption Systems

加密是将数据编码成密文的过程，这样只有预期的接收者才能解码和了解数据。这个项目推动了加密技术的发展。该项目的新奇之处在于构建具有先进功能的加密系统，这些系统在标准假设下具有可证明的安全性。这些功能包括跟踪泄露机密信息的恶意用户的功能，以及在需要知道的基础上仅向用户发布选定的信息片段的功能。该项目的影响是开发新一代加密系统，这些系统建立在可靠且经过测试的数学基础之上。该项目包括三个主要重点。(1)选择密文安全性。所选密文安全（IND-CCA）对于传统加密系统和具有高级功能的系统来说都是正确的安全概念。研究人员研究了将IND-CPA系统转换为IND-CCA系统的通用方法和新工具。(2)加密系统中的跟踪。叛逆者跟踪是确定广播系统中解码器的源的问题。研究人员探索了具有挑战性的新问题，包括：对任何常数c获得具有N^{1/c}大小的密文的跟踪和广播系统，实现对相同参数的公共可追溯性，并使用跟踪技术作为证明自适应安全性的工具。(3)基于带错误学习（LWE）假设的加密新领域。从LWE假设构建是一种令人兴奋的途径，可以从一个经过充分研究的假设中生成密码学中的新功能。研究人员将在这个方向上追求雄心勃勃的目标，包括混淆伪随机功能及其应用的新概念，以及从LWE开始构建见证加密的程序，其中一个中间目标是为比特固定功能构建约束伪随机函数。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Encryption is the process of encoding data into a ciphertext such that only the intended recipient can decode and learn the data. This project pushes the frontiers of what is achievable for encryption. The project's novelties are building encryption systems with advanced capabilities that have provable security under standard assumptions. These include the capability to trace malicious users who leak confidential information as well as the ability to only release select pieces of information to users on a need to know basis. The project's impacts are the development of a new generation of encryption systems that are built from reliable and tested mathematical underpinnings.The project consists of three primary thrusts. (1) Chosen ciphertext security. Chosen ciphertext security (IND-CCA) is arguably the right notion of security both for traditional encryption systems as well as ones with advanced functionality. The investigators investigate generic methods and new tools for converting IND-CPA systems into IND-CCA ones. (2) Tracing in encryption systems. Traitor tracing is the problem of determining the source of a decoder box in a broadcast system. The investigators explore challenging new problems including: getting trace and broadcast systems with N^{1/c} sized ciphertexts for any constant c, achieving public traceability for the same parameters and using tracing techniques as a tool for proving adaptive security. (3) New frontiers in encryption based on the Learning With Errors (LWE) assumption. Building from the LWE assumption is an exciting avenue for producing new functionality in cryptography from a well-studied assumption. The investigators will pursue ambitious goals in this direction, including a new concept of obfuscating pseudorandom functionalities and its applications, as well as a program for constructing witness encryption from LWE beginning with an intermediate goal of building constrained pseudorandom functions for the bit fixing functionality.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.