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Kien Tuong Truong

@kientuong114.bsky.social

PhD Student at ETH Zurich, Cryptography and more

6 Posts115 Follower104 Folgt
Miro Haller@mirohaller.bsky.social · 4w ago

You can also register to attend WAC8--the workshop on attacks in cryptography, an affiliated event with Crypto 2026--remotely (for free). Just fill out this google form: forms.gle/1anNohNaJmtA...

WAC8 Remote Registration

Sign up with an email address to receive the Zoom link to attend the workshop on attacks in cryptography 8 (WAC8) remotely. All information about the workshop is on our website: https://wac8.cryptanal...

forms.gle

Miro Haller@mirohaller.bsky.social · last mo.

Don't forget to register for WAC8! Early registration ends today (July 26). Below is our finalized WAC8 program with 8 exciting talks. More infos on: wac8.cryptanalysis.fun

Kien Tuong Truong@kientuong114.bsky.social · 6mo ago

@hjkl.space, @mirohaller.bsky.social, @laurahetz.bsky.social, Matilda and I are organizing CAW this year! Fun fact: a few talks that appeared at RWC this year have also been presented at CAW in prior years. Good track record! 10th May 2026, Rome caw.cryptanalysis.fun

Deirdre Connolly¹ ²@durumcrustulum.com · 6mo ago

@kientuong114.bsky.social matilda and matteo plug Cryptographic Applications Workshop at Eurocrypt in Rome caw.cryptanalysis.fun #realworldcrypto

Kien Tuong Truong@kientuong114.bsky.social · 6mo ago

Just finished presenting this work at Real World Crypto in Taipei :) TL;DR: We found 2 attacks on Signal (Android, Desktop) where a malicious server can inject messages in conversations. Super fun project! Thanks a bunch to Noemi Terzo, @kennyog.bsky.social, and @cryptojedi.bsky.social

ePrint Updates@eprint.ing.bot · 6mo ago

Signal Lost (Integrity): The Signal App is More than the Sum of its Protocols (Kien Tuong Truong, Noemi Terzo, Kenneth G. Paterson) ia.cr/2026/484

Abstract. Signal is a secure messaging app offering end-to-end security for pairwise and group communications. It has tens of millions of users, and has heavily influenced the design of other secure messaging apps (including WhatsApp). Signal has been heavily analysed and, as a result, is rightly regarded as setting the “gold standard” for messaging apps by the scientific community. We present two practical attacks that break the integrity properties of Signal in its advertised threat model. Each attack arises from different features of Signal that are poorly documented and have eluded formal security analyses. The first attack, affecting Android and Desktop, arises from Signal’s introduction of identities based on usernames (instead of phone numbers) in early 2022. We show that the protocol for resolving identities based on usernames and on phone numbers introduced a vulnerability that allows a malicious server to inject arbitrary messages into one-to-one conversations under specific circumstances. The injection causes a user-visible alert about a change of safety numbers, but if the users compare their safety numbers, they will be correct. The second attack is even more severe. It arises from Signal’s Sealed Sender (SSS) feature, designed to allow sender identities to be hidden. We show that a combination of two errors in the SSS implementation in Android allows a malicious server to inject arbitrary messages into both one-to-one and group conversations. The errors relate to missing key checks and the loss of context when cryptographic processing is distributed across multiple software components. The attack is undetectable by users and can be mounted at any time, without any preconditions. As far as we can tell, the vulnerability has been present since the introduction of SSS in 2018. We disclosed both attacks to Signal. The vulnerabilities were promptly acknowledged and patched: the first vulnerability was fixed two days after disclosure, while the second one was patched after eight days. Beyond presenting these devastating attacks on Signal’s end-to-end security guarantees, we discuss more broadly what can be learned about the challenges of deploying new security features in complex software projects.