TC: Small: New Directions in Encryption

新的应用场景（最明显的是云计算）引发了一系列新的安全问题。毫不奇怪，传统的加密概念在处理这些新的应用场景和问题时还有很多需要改进的地方。出于这些问题，我们开发新的加密系统，提供更大的功能比经典的加密概念。特别是，我们专注于两个广泛的研究方向：函数加密和有效的安全计算编码。在函数加密中，可以加密一般函数f，而不是加密给单个用户的消息。如果接收用户拥有某些凭证X，则其获得对应于那些凭证的秘密密钥SK-X。当该用户获得作为f的加密的密文时，通过应用解密算法，它获得f（X），而不是更多。 有效的安全计算编码是一个全新的概念，具有基本的应用，以新的表达加密方案，包括功能加密与公钥（最近介绍了PI下的术语？无忧加密？），最值得注意的是受控同态加密--在密文上可以有表达性的同态，但是初始的加密器可以控制允许什么样的同态。

New application scenarios (most notably arising from cloud computing) have given rise to a host of new security concerns. Unsurprisingly, classical notions of encryption leave much to be desired for dealing with these new application scenarios and concerns. Motivated by these concerns, we develop novel encryption systems that provide vastly greater functionality than classical notions of encryption. In particular, we focus on two broad research directions: Functional encryption and Efficient Secure Encodings of Computation. In functional encryption, instead of encrypting a message to an individual user, one can encrypt a general function f. If a receiving user possesses certain credentials X, then it obtains a secret key SK-X corresponding to those credentials. When this user obtains a ciphertext that is an encryption of f, by applying the decryption algorithm it obtains f(X), and no more. Efficient Secure Encodings of Computation is a totally new notion that has fundamental applications to novel expressive encryption schemes including functional encryption with public keys (recently introduced by the PI under the terminology ?Worry-Free Encryption?), and most notably controlled Homomorphic Encryption -- where expressive homomorphisms are possible on ciphertexts, but the initial encryptor can control what homomorphisms are allowed.