WAVE: A Decentralized Authorization Framework with Transitive Delegation

Hyung-Sin Kim Security, Systems

Most deployed authorization systems rely on a central trusted service whose compromise can lead to the breach of millions of user accounts and permissions. We present WAVE, an authorization framework offering decentralized trust: no central services can modify or see permissions and any participant can delegate a portion of their permissions autonomously. To achieve this goal, WAVE adopts an expressive authorization model, enforces it cryptographically, protects permissions via a novel encryption protocol while enabling discovery of permissions, and stores them in an untrusted scalable storage solution. WAVE provides competitive performance to traditional authorization systems relying on central trust. It is an open-source artifact and has been used for two years for controlling 800 IoT devices.

Authors: Michael Andersen, Sam Kumar, Moustafa AbdelBaky, Gabe Fierro, Jack Kolb, Hyung-Sin Kim, David Culler, Raluca Ada Popa

Oblix: An Efficient Oblivious Search Index

Pratyush Mishra Crypto, Security

Search indices are fundamental building blocks of many systems, and there is great interest in running them on encrypted data. Unfortunately, many known schemes that enable search queries on encrypted data achieve efficiency at the expense of security, as they reveal access patterns to the encrypted data. In this paper we present Oblix, a search index for encrypted data that is oblivious (provably hides access patterns), is dynamic (supports inserts and deletes), and has good efficiency. Oblix relies on a combination of novel oblivious-access techniques and recent hardware enclave platforms (e.g., Intel SGX). In particular, a key technical contribution is the design and implementation of doubly-oblivious data structures, in which the client’s accesses to its internal memory are oblivious, in …

Authors: Pratyush Mishra, Rishabh Poddar, Jerry Chen, Alessandro Chiesa, Raluca Ada Popa

SafeBricks: Shielding Network Functions in the Cloud

Rishabh Poddar Networks, Security, Systems

With the advent of network function virtualization (NFV), outsourcing network processing to the cloud is growing in popularity amongst enterprises and organizations. Such outsourcing, however, poses a threat to the security of the client’s traffic because the cloud is notoriously susceptible to attacks. We present SafeBricks, a system that shields generic network functions (NFs) from an untrusted cloud. SafeBricks ensures that only encrypted traffic is exposed to the cloud provider, and preserves the integrity of both traffic and the NFs. At the same time, it enables clients to reduce their trust in NF implementations by enforcing least privilege across NFs deployed in a chain. SafeBricks does not require changes to TLS, and safeguards the interests of NF vendors as well …

Authors: Rishabh Poddar, Chang Lan, Raluca Ada Popa, Sylvia Ratnasamy

Opaque: Secure Apache Spark SQL

Wenting Zheng blog, Security, Systems

As enterprises move to cloud-based analytics, the risk of cloud security breaches poses a serious threat. Encrypting data at rest and in transit is a major first step. However, data must still be decrypted in memory for processing, exposing it to any attacker who can observe memory contents. This is a challenging problem because security usually implies a tradeoff between performance and functionality. Cryptographic approaches like fully homomorphic encryption provide full functionality to a system, but are extremely slow. Systems like CryptDB utilize lighter cryptographic primitives to provide a practical database, but are limited in functionality. Recent developments in trusted hardware enclaves (such as Intel SGX) provide a much needed alternative. These hardware enclaves provide hardware-enforced shielded execution that allows …

Wenting Zheng is Awarded the 2017-18 IBM PhD Fellowship

Joseph Gonzalez Crypto, News, Security

Wenting Zheng was awarded the prestigious IBM PhD Fellowship for her work on  security and distributed systems. Wenting is actively studying new methods for scalable secure analytics, multi-party computation for machine learning, and distributed zero knowledge proofs.  The IBM Ph.D. fellowship is an “intensely competitive worldwide program that honors exceptional Ph.D. students who have an interest in solving problems that are important to IBM and fundamental to innovation in many academic disciplines and areas of study.” Only 50 fellowships are awarded worldwide annually.

MiniCrypt: Reconciling Encryption and Compression for Big Data Stores.

Raluca Ada Popa Security, Systems

More and more applications and web services generate larger and larger amounts of confidential data, such as user and financial data. On one hand, these systems must use encryption to ensure confidentiality, while on the other hand, they want to use compression to reduce costs and increase performance. Unfortunately, encryption and compression are in tension, leading many existing systems to support one but not the other. We propose MiniCrypt,  the first big data keyvalue store that reconciles encryption and compression, without compromising performance.  At the core of MiniCrypt is an observation on data compressibility trends in key-value stores, which enables grouping key-value pairs in small key packs, together with a set of new distributed systems techniques for retrieving, updating,  merging …

Authors: Wenting Zheng, Raluca Ada Popa, Ion Stoica, Rachit Agarwal, Frank Li

Opaque: An Oblivious and Encrypted Distributed Analytics Platform.

Raluca Ada Popa Crypto, Security, Systems

As enterprises move to cloud-based analytics, the risk of cloud security breaches poses a serious threat. Encrypting data at rest and in transit is a major first step. However, data must still be decrypted in memory for processing, exposing it to an attacker who has compromised the operating system or hypervisor. Trusted hardware such as Intel SGX has recently become available in latest-generation processors. Such hardware enables arbitrary computation on encrypted data while shielding it from a malicious OS or hypervisor. However, it still suffers from a significant side channel: access pattern leakage. We present Opaque, a package for Apache Spark SQL that enables very strong security for SQL queries: data encryption, computation verification, and access pattern leakage protection (a.k.a. …

Authors: Wenting Zheng, Raluca Ada Popa, Ion Stoica, Joseph Gonzalez, Ankur Dave, Jethro Beekman