Looking forward to co-organising this event with @jurajsomorovsky - send us your great talk proposals and papers before March 23rd (AoE).

RT @jurajsomorovsky: Come join us at the SPIQE workshop in Munich in June! - we are now open for paper submissions….

Brilliant and scary new paper from @kientuong114 and @jonas__hofmann to appear at ACM CCS 2024 - they analysed multiple "zero knowledge" E2EE cloud storage vendors' products and found major holes in their crypto architectures. "A broken ecosystem" indeed.

14/14.You can find other interesting open problems, our provably secure E2EE cloud storage construction, game-based security notions that are surprisingly compact, and pages of beautiful proofs , all in our full paper:

13/14.Another is to achieve advanced security properties that other E2EE primitives offer, such as FS and PCS, in the cloud storage setting.

12/14.To only mention a few: one is analysing whether our protocol achieves adaptive security, or if this can be achieved efficiently by another protocol based on standard cryptographic assumptions.

11/14.We discuss many challenges on the path towards bringing the security of cloud storage up to par with other end-to-end primitives, which should be interesting for future research.

10/14.Contribution 4: We present a design for an E2EE cloud storage system that supports all core functionality, is efficient and is provably secure with respect to our selective security notions.

9/14.Contribution 3: We put our models to the test and use them to formally capture some of the recent attacks on MEGA, showing our framework is rich enough to model deployed systems and capture practical attacks.

8/14.Contribution 2: We define game-based security notions for confidentiality and integrity of E2EE cloud storage against a fully malicious server, treating both selective and fully adaptive client compromises.

7/14.Contribution 1: We give a formal syntax capturing the core functionality of E2EE cloud storage while honouring the real-world complexity of such systems and supporting interactive protocols and out-of-band channels.

6/14.In this paper, we initiate the formal study of E2EE cloud storage and make four main contributions towards understanding the security of E2EE cloud storage and bringing it up to par with other E2EE applications.

5/14.Instead, deployed E2EE cloud storage protocols involve custom designs attempting to solve many complex cryptographic challenges, including password-based key management and file sharing, Despite this complexity, there's no formal guarantees to back up their security claims.

4/14.It turns out the security of E2EE cloud storage lags behind that of other E2EE applications like secure messaging. There is no rigorous foundation, no security notions, and no provably secure protocols.

3/14.Users increasingly store their data in the cloud for easy access, sharing, and redundancy. E2EE should protect the data even against server compromise. However, recent research from my group has discovered attacks against widely deployed systems including MEGA and Nextcloud.

2/14.This is joint work with Matilda Backendal (@CSatETH @ETH_en @ETH), Hannah Davis (@Seagate), Felix Günther (@IBMResearch), and Miro Haller (@miro_haller @ucsd_cse @UCSanDiego). This thread contains the highlights, full version:

1/14.A Formal Treatment of End-to-End Encrypted Cloud Storage (Crypto'24): in this new paper we designed an E2EE cloud storage protocol and prove it secure in novel game-based confidentiality and integrity notions that capture real-world complexities and malicious servers.

RT @PresidentIRL: Best wishes to all who are participating in Take Your Dog to Work Day today

RT @mitrokat: Swiss Crypto Day 2024 is taking place @HSGStGallen on the 2nd of Sept! 📢 Register now✍️and nominate talks 🎙️ Spread the word….

RT @DollyBenga: Only the second biggest lie emblazoned on a bus x