SaTC: CORE: Small: New Cryptographic Capabilities for a Quantum World

量子技术的出现为加密能力的发展开辟了新的途径，否则这些能力是不可能实现的。例如，一旦攻击者获得了对一串数据的访问权，他们可能会存储该串的任意多个副本，并且没有办法验证该串是否真的被删除。即使字符串是对底层明文进行编码的密文，攻击者也可以永远保留该密文，或者将其许多副本分发给恶意实体。如果基础加密方案的安全性在将来失效，或者如果密钥被泄露，恶意实体可能能够恢复明文-这对于高度敏感的数据来说可能是不可接受的。另一方面，未知的量子态不能被复制，对这些状态的测量具有固有的破坏性和不可逆性。这提出了通过将信息编码成量子态来构建具有强删除和不可克隆特性的密码系统的令人兴奋的可能性。该研究项目通过将数学硬度与量子信息特性产生的安全性仔细结合来实现这些功能。第一个研究重点是开发支持敏感数据可验证删除的密码系统-这些包括高级加密方案，外包给不可信服务器的方法和分布式安全计算。这些方案允许不受信任的设备和服务器证明他们永远删除或删除了私人记录-即使在他们已经访问或计算了这些记录的编码之后。第二个重点是以密码学上有用的方式加强量子不可克隆原则，为不可克隆密码学奠定坚实的基础。这导致密码系统可以防止对手将量子编码分裂成两个或更多个状态，从而有意义地编码潜在的秘密。该项目还为密码学研究人员建立指导计划和研讨会，并开发临时材料，以使下一代研究人员受益。该奖项反映了NSF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。

The emergence of quantum technologies opens up new avenues for the development of cryptographic capabilities that would otherwise have been impossible to achieve. For example, once an adversary gains access to a string of data, they may store arbitrarily many copies of this string and there is no way to verify that the string was truly deleted. Even if the string is a ciphertext encoding an underlying plaintext, an adversary can always keep that ciphertext around forever or distribute many copies of it to malicious entities. If security of the underlying encryption scheme breaks down in the future, or if the key is compromised, malicious entities may be able to recover the plaintext – and this may be unacceptable for highly sensitive data. On the other hand, unknown quantum states cannot be copied, and measurements on these states are inherently destructive and irreversible. This raises the exciting possibility of building cryptosystems with strong deletion and unclonability properties by encoding information into quantum states. This research project enables these capabilities by carefully combining mathematical hardness with security that arises from the properties of quantum information. The first research focus develops cryptosystems that support verifiable deletion of sensitive data – these include advanced encryption schemes, methods of outsourcing to untrusted servers, and distributed secure computation. These schemes allow untrusted devices and servers to prove that they deleted or erased private records forever – even after they already had access to, or computed on, encodings of these records. The second focus strengthens the quantum no-cloning principle in cryptographically useful ways, to build strong foundations for unclonable cryptography. This leads to cryptosystems that prevent an adversary from splitting a quantum encoding into two or more states that meaningfully encode an underlying secret. The project also establishes mentoring programs and seminars for cryptography researchers and develops expository material to benefit an upcoming generation of researchers.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.