Mitigating Leakage in Secure Cloud-Hosted Data Structures

Patel, Sarvar; Persiano, Giuseppe; Yeo, Kyongmin; Yung, Moti

doi:10.1145/3319535.3354213

Cited by 75 publications

(133 citation statements)

References 44 publications

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“…The storage overhead of AVLH is comparable to the overhead of BSL. Recent volume-hiding results by Patel, Persiano, Yeo and Yung [61] show how to get even better query complexity and storage overhead.…”

Section: Countermeasuresmentioning

confidence: 99%

Revisiting Leakage Abuse Attacks

Blackstone¹,

Kamara

Moataz

2020

Proceedings 2020 Network and Distributed System Security Symposium

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Encrypted search algorithms (ESA) are cryptographic algorithms that support search over encrypted data. ESAs can be designed with various primitives including searchable/structured symmetric encryption (SSE/STE) and oblivious RAM (ORAM). Leakage abuse attacks attempt to recover client queries using knowledge of the client's data. An important parameter for any leakage-abuse attack is its known-data rate; that is, the fraction of client data that must be known to the adversary. In this work, we revisit leakage abuse attacks in several ways. We first highlight some practical limitations and assumptions underlying the well-known IKK (Islam et al. NDSS '12) and Count (Cash et al., CCS '15) attacks. We then design four new leakage-abuse attacks that rely on much weaker assumptions. Three of these attacks are volumetric in the sense that they only exploit leakage related to document sizes. In particular, this means that they work not only on SSE/STE-based ESAs but also against ORAM-based solutions. We also introduce two volumetric injection attacks which use adversarial file additions to recover queries even from ORAM-based solutions. As far as we know, these are the first attacks of their kind. We evaluated all our attacks empirically and considered many experimental settings including different data collections, query selectivities, known-data rates, query space size and composition. From our experiments, we observed that the only setting that resulted in reasonable recovery rates under practical assumptions was the case of high-selectivity queries with a leakage profile that includes the response identity pattern (i.e., the identifiers of the matching documents) and the volume pattern (i.e., the size of the matching documents). All other attack scenarios either failed or relied on unrealistic assumptions (e.g., very high known-data rates). For this specific setting, we propose several suggestions and countermeasures including the use of schemes like PBS (Kamara et al, CRYPTO '18), VLH/AVLH (Kamara and Moataz, Eurocrypt '19), or the use of padding techniques like the ones recently proposed by Bost and Fouque (Bost and Fouque, IACR ePrint 2017/1060).

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Section: Countermeasuresmentioning

confidence: 99%

Revisiting Leakage Abuse Attacks

Blackstone¹,

Kamara

Moataz

2020

Proceedings 2020 Network and Distributed System Security Symposium

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“…To an adversary observing memory accesses to the cuckoo tables, those two cases are indistinguishable. This feature makes cuckoo hashing attractive as a basis for oblivious hashing algorithms [CGLS17], with applications to Oblivious RAM and other cryptographic constructions, such as differentially-private SSE [PPYY19].…”

Section: Discussionmentioning

confidence: 99%

SSE and SSD: Page-Efficient Searchable Symmetric Encryption

Bossuat

Bost

Fouque

et al. 2021

Lecture Notes in Computer Science

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Searchable Symmetric Encryption (SSE) enables a client to outsource a database to an untrusted server, while retaining the ability to securely search the data. The performance bottleneck of classic SSE schemes typically does not come from their fast, symmetric cryptographic operations, but rather from the cost of memory accesses. To address this issue, many works in the literature have considered the notion of locality, a simple design criterion that helps capture the cost of memory accesses in traditional storage media, such as Hard Disk Drives. A common thread among many SSE schemes aiming to improve locality is that they are built on top of new memory allocation schemes, which form the technical core of the constructions.The starting observation of this work is that for newer storage media such as Solid State Drives (SSDs), which have become increasingly common, locality is not a good predictor of practical performance. Instead, SSD performance mainly depends on page efficiency, that is, reading as few pages as possible. We define this notion, and identify a simple memory allocation problem, Data-Independent Packing (DIP), that captures the main technical challenge required to build page-efficient SSE. As our main result, we build a page-efficient and storage-efficient data-independent packing scheme, and deduce the Tethys SSE scheme, the first SSE scheme to achieve at once O(1) page efficiency and O(1) storage efficiency. The technical core of the result is a new generalization of cuckoo hashing to items of variable size. Practical experiments show that this new approach achieves excellent performance.

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“…To enable detection, analysis, or process on encrypted traffic with outsourced (encrypted) network functions, more information will be disclosed than the traditional unmanageable encrypted packets (e.g., HTTPs traffic). For example, the SSE-based methods may be vulnerable to the leakage-abuse attacks [141], [147], [149], [150]. The deterministic search tokens reveal the statistical distribution of the traffic.…”

Section: Attacks On Outsourced Network Functionsmentioning

confidence: 99%