标题： 被阻止的无意识伪随机函数 显示英文标题

标题： Blocklisted Oblivious Pseudorandom Functions

摘要： 一种不可见伪随机函数（OPRF）是一种协议，通过该协议，客户端和服务器交互以在由服务器提供的密钥和由客户端提供的输入上评估伪随机函数，而不会将密钥或输入泄露给对方。 我们通过使服务器能够指定一个黑名单来扩展这一概念，使得只有当客户端的输入不在黑名单中时，OPRF的计算才能成功。 更具体地说，我们的设计通过将客户端输入嵌入到一个度量空间中来获得性能提升，只有当此嵌入不与黑名单元素聚集时，计算才会继续。 我们的框架利用这种结构来分离嵌入和黑名单检查，以实现每个部分的高效实现，但随后必须通过密码学手段将这些阶段连接起来。 我们的框架还支持对同一输入的OPRF的后续高效计算。 我们展示了该设计在增强型密码认证密钥交换中的密码黑名单应用，以及仅对不与已知恶意软件黑名单中的程序相似的可执行文件进行消息认证码（MAC）处理的应用。 显示英文摘要

摘要： An oblivious pseudorandom function (OPRF) is a protocol by which a client and server interact to evaluate a pseudorandom function on a key provided by the server and an input provided by the client, without divulging the key or input to the other party. We extend this notion by enabling the server to specify a blocklist, such that OPRF evaluation succeeds only if the client's input is not on the blocklist. More specifically, our design gains performance by embedding the client input into a metric space, where evaluation continues only if this embedding does not cluster with blocklist elements. Our framework exploits this structure to separate the embedding and blocklist check to enable efficient implementations of each, but then must stitch these phases together through cryptographic means. Our framework also supports subsequent evaluation of the OPRF on the same input more efficiently. We demonstrate the use of our design for password blocklisting in augmented password-authenticated key exchange, and to MAC only executables that are not similar to ones on a blocklist of known malware.