sasha
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sasha.place
sasha
@sasha.place
120 followers 180 following 88 posts
PhD Student at UMD studying Cryptography
website: sasha.place
Formerly at Meta/Cornell
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sasha.place
who came up with this MPC model? Dr. Doofenschmirtz?
October 28, 2025 at 11:34 PM
Reposted by sasha
eprint.ing.bot
Cryptographic Personas: Responsible Pseudonyms Without De-Anonymization (Rachel Thomas, Oliwia Kempinski, Hari Kailad, Emma Margaret Shroyer, Ian Miers, Gabriel Kaptchuk) ia.cr/2025/1969
Abstract. We present cryptographic personas, an approach for facilitating access to pseudonymous speech within communities without enabling abuse. In systems equipped with cryptographic personas, users are able to authenticate to the service provider under new, unlinkable personas at will and post messages under those personas. When users violate community norms, their ability to post anonymously can be revoked. We develop two significant improvements to existing work on anonymous banning systems that make it possible to integrate cryptographic personas into real-time applications like group messaging: we show how to push expensive proof generation into an offline phase and find a way to optimize server-side overhead using recent proof folding techniques. We implement cryptographic personas, integrating them into a variety of settings, and show that they are concretely efficient enough for deployment.
October 22, 2025 at 2:31 PM
sasha.place
I met somebody who appears in the Enron dataset a few times tonight! She was a fairly high ranking energy attorney who was working with their lobbyists a lot around 2000. it was a really fun obscure celebrity encounter.
October 24, 2025 at 2:34 AM
sasha.place
New preprint! It's still in submission, I will write a thread/blogpost about it when it gets accepted.
eprint.ing.bot ePrint Updates @eprint.ing.bot · Oct 20
zk-Cookies: Continuous Anonymous Authentication for the Web (Alexander Frolov, Hal Triedman, Ian Miers) ia.cr/2025/1938
Abstract. We are now entering an era where the large-scale deployment of anonymous credentials seems inevitable, driven both by legislation requiring age verification and the desire to distinguish humans from bots in the face of the proliferation of AI-generated content. However, the widespread deployment of anonymous credentials faces the same security and fraud concerns as existing credentials, but without the established techniques for securing them. For non-anonymous credentials on the web today, authentication is a continuous process in which servers collect large volumes of behavioral data to protect account holders (e.g., by detecting account compromise) or to combat fraudulent behavior. In this paper, we propose Continuous Anonymous Authentication (CAA) schemes and give a concrete construction and applications for preventing credential sharing and theft. CAA schemes allow us to move the server-side collection, storage, and processing of these behavioral signals to the client while maintaining privacy and integrity. CAA schemes support, on the client side, a number of common behavioral analysis tests and analytics both for determining fraudulent behavior and updating security policies. We implement a prototype, zk-Cookies, which runs in the browser, and supports common behavioral signals such as IP address and geolocation history, browser fingerprinting, and page view history. Using this, we build a prototype application for age verification based on legacy credentials (like passports). We implement these checks efficiently in zk-SNARKs, and also show how to securely implement differentially private behavioral analytics in a zk-SNARK. The simplest version of our construction can perform the computation for an update in under 200 ms. Image showing part 2 of abstract.
October 20, 2025 at 1:27 AM
sasha.place
here's a problem i have been thinking about for a bit, which i was reminded of by an online argument today. wanted to rant a little.
there is currently a pretty big demand for consultants to work on quantum computing and post-quantum crypto in industry.
October 15, 2025 at 2:28 PM
sasha.place
I want to make a thread, that I will maybe convert into a blog post, of cryptography things that I have found really hard to google.
October 5, 2025 at 2:07 PM
sasha.place
🇵🇱🇵🇱🇵🇱🇵🇱 Polish benchmark 🇵🇱🇵🇱🇵🇱🇵🇱 RAAAAA 🇵🇱🇵🇱🇵🇱🇵🇱
September 21, 2025 at 2:15 AM
sasha.place
this week is my 1 year anniversary of starting grad school. I have been reading 1-2 papers (or equivalent amount of a textbook) per week most of the time. here is the list of papers i have read since starting. I am pretty proud of it! here is a list of papers that were highlights:
August 29, 2025 at 6:09 PM
sasha.place
writing "i.e.g." to hedge my bets against using the wrong acronym
August 6, 2025 at 9:36 PM
sasha.place
i now realize that this reviewer (who bid for an applied crypto paper) does not seem to know what a commitment scheme or PRF is, in addition to probably asking us to cite their paper
sasha.place sasha @sasha.place · Aug 1
working through updating my paper based on the reviews, and one of the reviewers almost certainly asked me to cite their (superficially looks related but isn't) paper
sasha.place sasha @sasha.place · Jul 22
3 of the 4 reviews were at least decent reviews with actionable suggestions, but one was mean and condescending and wrong.
August 3, 2025 at 6:44 PM
sasha.place
working through updating my paper based on the reviews, and one of the reviewers almost certainly asked me to cite their (superficially looks related but isn't) paper
sasha.place sasha @sasha.place · Jul 22
3 of the 4 reviews were at least decent reviews with actionable suggestions, but one was mean and condescending and wrong.
August 1, 2025 at 2:21 PM
sasha.place
ticketmaster is officially headquartered in West Virginia? kind of interesting
July 27, 2025 at 9:05 PM
sasha.place
got my first conference rejections (2 for S&P).
July 22, 2025 at 1:49 AM
sasha.place
one of my hobbies is reading crank papers on eprint.iacr.org. Most AI-generated papers seem to exist to try to fool other people, but a scary number of them seem to involve somebody being convinced they have made a major discovery by an LLM
July 17, 2025 at 9:33 PM
sasha.place
i wish i was over 6 feet tall so i could use the "long fellow" crypto library :(

github.com/google/longf...
GitHub - google/longfellow-zk: Implementation of the Google Zero-Knowledge library for Identity Protocols.
Implementation of the Google Zero-Knowledge library for Identity Protocols. - google/longfellow-zk
github.com
July 4, 2025 at 6:27 PM
sasha.place
the billing code for shoulder pain is 25.519! cryptography is everywhere!
July 2, 2025 at 8:47 PM
sasha.place
im working on my first 2 subreview papers ever! both are pretty good papers! it is giving me optimism about the state of the field
June 26, 2025 at 3:42 AM
sasha.place
I wrote a blog post about some (hopefully non-obvious) thoughts about the differences between big tech and academia: www.sasha.place/blog/2025/06...
Some thoughts on industry vs. academia 1 year into grad school
As of the time of writing this blog post, it has been about a year since I left my job at Meta to go to grad school. People somewhat frequently ask me about ...
www.sasha.place
June 25, 2025 at 5:46 PM
sasha.place
I really liked this blog post explaining this internet math meme from a few years ago

vitalik.eth.limo/general/2025...
June 14, 2025 at 1:14 AM
sasha.place
solving the poop equation tonight
June 13, 2025 at 6:39 PM
Reposted by sasha
eprint.ing.bot
How to Trace Viral Content in End-to-End Encrypted Messaging (Pedro Branco, Matthew Green, Aditya Hegde, Abhishek Jain, Gabriel Kaptchuk) ia.cr/2025/1052
Abstract. We study the problem of combating viral misinformation campaigns in end-to-end encrypted (E2EE) messaging systems such as WhatsApp. We propose a new notion of Hop Tracking Signatures (HTS) that allows for tracing originators of messages that have been propagated on long forwarding paths (i.e., gone viral), while preserving anonymity of everyone else. We define security for HTS against malicious servers. We present both negative and positive results for HTS: on the one hand, we show that HTS does not admit succinct constructions if tracing and anonymity thresholds differ by exactly one “hop”. On the other hand, by allowing for a larger gap between tracing and anonymity thresholds, we can build succinct HTS schemes where the signature size does not grow with the forwarding path. Our positive result relies on streaming algorithms and strong cryptographic assumptions. Prior works on tracing within E2EE messaging systems either do not achieve security against malicious servers or focus only on tracing originators of pre-defined banned content. Image showing part 2 of abstract.
June 6, 2025 at 3:23 AM
sasha.place
submitted to S&P
June 6, 2025 at 6:18 AM
sasha.place
4 days to IEEE S&P deadline. stuck in the phase of paper writing where people keep asking me to slightly change the intro and framing paragraphs of various sections.
June 2, 2025 at 3:57 PM
sasha.place
It's a week left until the IEEE S&P deadline and this video's (youtu.be/H2Mb-0QrYw0?...) idea of the "finishing gulch" really resonated with me.
"I've been working on a thing for weeks [...] Every clever line is stale. Every interesting fact that pulled me into the story is something that I've just
Dan Olson, Folding Ideas - XOXO Festival (2024)
YouTube video by XOXO Festival
youtu.be
May 30, 2025 at 2:57 AM
sasha.place
when overleaf hits you with the big-ass f
May 27, 2025 at 2:26 PM