Securing Communications after Device Compromise

密码学中的传统对手模型主要关注无法访问端点的网络对手。我们现在知道这是naïve -由于当前的安全架构，具有物理访问权限的攻击者可以访问他们通信的所有过去和未来的密钥。之前解决这个问题的尝试包括前向保密的概念，这是一种加密属性，可以确保一个秘密（例如密钥）的泄露不会导致所有未来的秘密泄露。这可以通过键棘轮或键旋转来完成，在每次会话之后更新密钥。与身份验证相关的一种技术是恐慌密码，它会提醒第三方注意胁迫—当然，这是假设攻击者不知道这种隐蔽机制，这是一个弱模型。该项目将从开发一个新的安全模型开始，以对抗强大的物理对手——我们认为以前的模型不能满足我们新模型中的某些安全属性。反过来，我们将开发新的加密技术来减轻威胁，并提供可证明的安全保证。该项目将特别适用于应对内部威胁、亲密伙伴威胁以及身份验证过程中的通信胁迫，包括电子投票。该项目属于EPSRC全球不确定性研究领域。

Traditional adversary models in cryptography focus primarily on a network adversary with no access to endpoints. We now know that this was naïve - due to current security architectures, an adversary with physical access may have access to all past and future secret keys for their communications. Previous attempts at solving this problem include the notion of forward secrecy, a cryptographic property which ensures that compromise of a secret (e.g. key) does not lead to compromise of all future secrets. This can be done by key ratcheting or key rotation, which updates the secret key after every session. A related technique on authentication is panic password, which would alert a third party of the duress - this is of course assuming that the adversary isn't aware of this covert mechanism, which makes for a weak model.The project will start with developing a new security model against a strong physical adversary - we argue that the previous models do not satisfy certain security properties in our new model. In turn, we will develop new cryptographic techniques to mitigate the threats, with provably secure guarantees. This project will be relevant in particular against insider threat, intimate partner threat, as well as communicating duress during authentication, including e-Voting.This project falls within the EPSRC Global Uncertainties research area.