Chris Peikert
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chrispeikert.bsky.social
Chris Peikert
@chrispeikert.bsky.social
500 followers 35 following 99 posts
Cryptographer (lattices/post-quantum), Professor at U-Michigan Computer Science and Engineering , Head of Cryptography Research at Algorand, PhD from MIT CSAIL. Previously faculty at Georgia Tech School of CS. Here I speak for myself.
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Reposted by Chris Peikert
donmoyn.bsky.social
This is so deeply at odds with the vision and history of America. Take pretty much any ethnic or racial group that are part of the American mosaic America today - they have all faced the same accusation. The moment these accusations are turned into policy are some of the most shameful in US history
publius24.bsky.social John Q. Public @publius24.bsky.social · 4d
Stephen Miller is now arguing that assimilation is fundamentally impossible and that certain cultures are not compatible with Western civilization
November 28, 2025 at 1:58 PM
Reposted by Chris Peikert
volts.wtf
An 18yo US citizen, surrounded by eight masked, armed agents of the state, taken into custody, not read his rights, not offered a chance to contact a lawyer, proof of citizenship ignored, handcuffed so tightly he later required medical attention.

Profoundly, profoundly anti-American shit.
ICE Detained an 18-Year-Old U.S. Citizen. This Is His Story.
YouTube video by The Hometown Holler
youtu.be
November 26, 2025 at 10:00 PM
Reposted by Chris Peikert
radleybalko.bsky.social
Kavanaugh stop. Smashed the kid’s car windows and arrested him. He told them he was a U.S. citizen. The officer replied “I don’t care.”

www.oregonlive.com/portland/202...
High school senior, a U.S. citizen, detained by ICE in Oregon
The 17-year-old was held more than five hours Friday in an ICE facility, his brother said.
www.oregonlive.com
November 23, 2025 at 12:34 AM
chrispeikert.bsky.social
Eagerly awaiting the first paper titled “F’N-DSA”

(on security vulnerabilities arising from incorrect implementation of floating-point arithmetic in FIPS-206)
November 22, 2025 at 11:32 AM
chrispeikert.bsky.social
Time to update the title of this classic paper!

dl.acm.org/doi/10.5555/...
November 22, 2025 at 11:25 AM
Reposted by Chris Peikert
reichlinmelnick.bsky.social
THREAD: Judge Ellis is the first federal judge to review extensive body cam video of DHS's actions in Chicago. She finds that DHS *repeatedly* misled the public and made claims that were disproven by agents' own videos.

I'll go through some of the most egregious ones here.
II. Credibility The Court next addresses the credibility of the parties’ evidence and witnesses. After reviewing all the evidence submitted to the Court and listening to the testimony elicited at the preliminary injunction hearing, during depositions, and in other court proceedings, the Court finds Defendants’ evidence simply not credible. [FN 6] Plaintiffs submitted a mountain of evidence, providing the Court with over eighty declarations, numerous videos and articles, and other evidence. Defendants did not rebut anything that Plaintiffs set forth in their declarations or testimony, even with BWC footage. [FN 6] In another case considering some of the same evidence presented to this Court, another court in this district also found that the perceptions of certain of Defendants’ declarants, such as Hott and Parra, were not reliable. See Illinois v. Trump, No. 25-cv-12174, 2025 WL 2886645, at *5 (N.D. Ill. Oct. 10, 2025) (noting a “troubling trend of Defendants’ declarants equating protests with riots and a lack of appreciation for the wide spectrum that exists between citizens who are observing, questioning, and criticizing their government, and those who are obstructing, assaulting, or doing violence”), motion to stay denied in part, 155 F.4th 929 (7th Cir. 2025).
November 20, 2025 at 11:04 PM
chrispeikert.bsky.social
This is mathematics erasure, Spelling Bee.
Spelling Bee choice of CODOMAIN: “not in word list” Spelling Bee choice of MONIC: “not in word list” Spelling Bee choice of MONADIC: “not in word list” Spelling Bee choice of COMONAD: “not in word list”
November 13, 2025 at 12:16 PM
Reposted by Chris Peikert
chrislhayes.bsky.social
Also, maybe we come up with, like, two more holidays, say in the early and late spring, that involve walking around the neighborhood and talking to your neighbors?
October 31, 2025 at 10:56 PM
Reposted by Chris Peikert
radleybalko.bsky.social
This is ugly. But the reason this lady was protesting is even worse. ICE thugs detained two children and their father on their way to school. One child appears to have been beaten in detention, and no one seems to know where the 12-year-old girl is right now. The family had been seeking asylum.
Shock Video Shows ICE Agent Assaulting Woman Who Asked If He’s A Good Christian
Hundreds protested Tuesday at an ICE facility in southwest Colorado after agents detained two children on their way to school.
www.huffpost.com
October 29, 2025 at 10:00 PM
chrispeikert.bsky.social
and of my research pathway
gbodwin.bsky.social Greg Bodwin @gbodwin.bsky.social · Oct 28
this is a pretty accurate summary of my research area
October 28, 2025 at 3:05 PM
Reposted by Chris Peikert
normative.bsky.social
Must have taken a wrong turn on the way to the “Hate America rally”; all I see are American flags & signs promoting the Constitution, liberty, & democracy.
No kings protest in DC
October 18, 2025 at 4:19 PM
chrispeikert.bsky.social
We’re thrilled to receive a Distinguished Paper Award for this work!

www.sigsac.org/ccs/CCS2025/...
October 16, 2025 at 11:19 AM
chrispeikert.bsky.social
⚡New paper⚡, with Guy Zyskind, Doron Zarchy, and Max Leibovich of Fhenix, presented today at ACM CCS.

We give an efficient 𝒕𝒉𝒓𝒆𝒔𝒉𝒐𝒍𝒅 𝒅𝒆𝒄𝒓𝒚𝒑𝒕𝒊𝒐𝒏 protocol for FHE/LWE with: no "noise flooding" or parameter loss, simulation (UC) security, and high throughput.

web.eecs.umich.edu/~cpeikert/pu...
Title: High-Throughput Universally Composable Threshold FHE Decryption by Guy Zyskind, Doron Zarchy, Max Leibovich, and Chris Peikert Threshold Fully Homomorphic Encryption (FHE) enables arbitrary computation on encrypted data, while distributing the decryption capability across multiple parties. A primary application of interest is low-communication multi-party computation (MPC), which benefits from a fast and secure threshold FHE decryption protocol. Several works have addressed this problem, but all existing solutions rely on "noise flooding" for security. This incurs significant overhead and necessitates large parameters in practice, making it unsuitable for many real-world deployments. Some constructions have somewhat better efficiency, but at the cost of weaker, non-simulation-based security definitions, which limits their usability and composability. In this work, we propose a novel threshold FHE decryption protocol that avoids "noise flooding" altogether, and provides simulation-based security. Rather than masking the underlying ciphertext noise, our technique securely removes it via an efficient MPC rounding procedure. The cost of this MPC is mitigated by an offline/online design that preprocesses special gates for secure comparisons in the offline phase, and has low communication and computation in the online phase. This approach is of independent interest, and should also benefit other MPC protocols (e.g., secure machine learning) that make heavy use of non-linear comparison operations. We prove our protocol secure in the Universal Composability (UC) framework, and it can be generally instantiated for a variety of adversary models (e.g., security-with-abort against a dishonest majority, or guaranteed output delivery with honest majority). Compared to the state of the art, our protocol offers significant gains both in the adversary model (i.e., dishonest vs. honest majority) and practical performance: empirically, our online phase obtains approximately 20,000x better throughput, and up to a 37x improvement in latency.
October 14, 2025 at 3:40 PM
chrispeikert.bsky.social
⚡New paper⚡, with Alexandra Veliche Hostetler!

We give a list-decoding algorithm for Reed-Solomon codes, where the error is measured in the Euclidean (ℓ₂) or Lee (ℓ₁) metrics, rather than the Hamming metric (as is more typical).

web.eecs.umich.edu/~cpeikert/pu...
Title: List Decoding Reed--Solomon Codes in the Lee, Euclidean, and Other Metrics Abstract: Reed--Solomon error-correcting codes are ubiquitous across computer science and information theory, with applications in cryptography, computational complexity, communication and storage systems, and more. Most works on efficient error correction for these codes, like the celebrated Berlekamp--Welch unique decoder and the (Guruswami--)Sudan list decoders, are focused on measuring error in the Hamming metric, which simply counts the number of corrupted codeword symbols. However, for some applications, other metrics that depend on the specific values of the errors may be more appropriate. This work gives a polynomial-time algorithm that list decodes (generalized) Reed--Solomon codes over prime fields in $\ell_p$ (semi)metrics, for any $0 < p \leq 2$. Compared to prior algorithms for the Lee ($\ell_1$) and Euclidean ($\ell_2$) metrics, ours decodes to arbitrarily large distances (for correspondingly small rates), and has better distance-rate tradeoffs for all decoding distances above some moderate thresholds. We also prove lower bounds on the $\ell_{1}$ and $\ell_{2}$ minimum distances of a certain natural subclass of GRS codes, which establishes that our list decoder is actually a unique decoder for many parameters of interest. Finally, we analyze our algorithm's performance under *random* Laplacian and Gaussian errors, and show that it supports even larger rates than for corresponding amounts of worst-case error in $\ell_{1}$ and $\ell_{2}$ (respectively).
October 13, 2025 at 2:53 PM
chrispeikert.bsky.social
This was an hour ago!
chrislhayes.bsky.social Chris Hayes @chrislhayes.bsky.social · Oct 11
This game is deranged.
October 11, 2025 at 5:05 AM
Reposted by Chris Peikert
jameeljaffer.bsky.social
MIT's response to the Trump admin's proposed "compact" is excellent and should be a model for other universities. orgchart.mit.edu/letters/rega...
October 10, 2025 at 2:14 PM
Reposted by Chris Peikert
eprint.ing.bot
FrodoKEM: A CCA-Secure Learning With Errors Key Encapsulation Mechanism (Lewis Glabush, Patrick Longa, Michael Naehrig, Chris Peikert, Douglas Stebila, Fernando Virdia) ia.cr/2025/1861
Abstract. Large-scale quantum computers capable of implementing Shor’s algorithm pose a significant threat to the security of the most widely used public-key cryptographic schemes. This risk has motivated substantial efforts by standards bodies and government agencies to identify and standardize quantum-safe cryptographic systems. Among the proposed solutions, lattice-based cryptography has emerged as the foundation for some of the most promising protocols. This paper describes FrodoKEM, a family of conservative key-encapsulation mechanisms (KEMs) whose security is based on generic, “unstructured” lattices. FrodoKEM is proposed as an alternative to the more efficient lattice schemes that utilize algebraically structured lattices, such as the recently standardized ML-KEM scheme. By relying on generic lattices, FrodoKEM minimizes the potential for future attacks that exploit algebraic structures while enabling simple and compact implementations. Our plain C implementations demonstrate that, despite its conservative design and parameterization, FrodoKEM remains practical. For instance, the full protocol at NIST security level 1 runs in approximately 0.97 ms on a server-class processor, and 4.98 ms on a smartphone-class processor. FrodoKEM obtains (single-target) IND-CCA security using a variant of the Fujisaki-Okamoto transform, applied to an underlying public-key encryption scheme called FrodoPKE. In addition, using a new tool called the Salted Fujisaki-Okamoto (SFO) transform, FrodoKEM is also shown to tightly achieve multi-target security, without increasing the FrodoPKE message length and with a negligible performance impact, based on the multi-target IND-CPA security of FrodoPKE. Image showing part 2 of abstract.
October 8, 2025 at 4:55 AM
Reposted by Chris Peikert
juddlegum.bsky.social
1. Federal agents from ICE and other agencies are wrongly detaining U.S. citizens, sometimes detaining them for days, on suspicion that they are undocumented immigrants.

The raids are done without search warrants or other procedures designed to protect civil liberties.
How federal agents are terrorizing American citizens
Last week, hundreds of heavily armed federal agents descended on an apartment complex in Chicago, arriving in Black Hawk helicopters and moving trucks.
popular.info
October 6, 2025 at 1:17 PM
Reposted by Chris Peikert
kristinacooke.bsky.social
I spoke to a Venezuelan woman who was arrested in this raid and later released with her 4yo son. She said agents broke down their door, pointed guns at them and made sexualized remarks about Venezuelan women. When she returned to her apartment it was boarded up and all her possessions were gone.
October 4, 2025 at 2:30 PM
Reposted by Chris Peikert
govpritzker.illinois.gov
This morning, the Trump Administration’s Department of War gave me an ultimatum: call up your troops, or we will. It is absolutely outrageous and un-American to demand a Governor send military troops within our own borders and against our will.
October 4, 2025 at 6:10 PM
Reposted by Chris Peikert
govpritzker.illinois.gov
Yesterday, Kristi Noem’s and Greg Bovino’s masked agents threw chemical agents near an elementary school, arrested elected officials exercising their First Amendment rights, and raided a Wal-Mart.
October 4, 2025 at 6:10 PM
Reposted by Chris Peikert
eprint.ing.bot
High-Throughput Universally Composable Threshold FHE Decryption (Guy Zyskind, Doron Zarchy, Max Leibovich, Chris Peikert) ia.cr/2025/1781
Abstract. Threshold Fully Homomorphic Encryption (FHE) enables arbitrary computation on encrypted data, while distributing the decryption capability across multiple parties. A primary application of interest is low-communication multi-party computation (MPC), which benefits from a fast and secure threshold FHE decryption protocol. Several works have addressed this problem, but all existing solutions rely on “noise flooding” for security. This incurs significant overhead and necessitates large parameters in practice, making it unsuitable for many real-world deployments. Some constructions have somewhat better efficiency, but at the cost of weaker, non-simulation-based security definitions, which limits their usability and composability. In this work, we propose a novel threshold FHE decryption protocol that avoids “noise flooding” altogether, and provides simulation-based security. Rather than masking the underlying ciphertext noise, our technique securely removes it via an efficient MPC rounding procedure. The cost of this MPC is mitigated by an offline/online design that preprocesses special gates for secure comparisons in the offline phase, and has low communication and computation in the online phase. This approach is of independent interest, and should also benefit other MPC protocols (e.g., secure machine learning) that make heavy use of non-linear comparison operations. We prove our protocol secure in the Universal Composability (UC) framework, and it can be generally instantiated for a variety of adversary models (e.g., security-with-abort against a dishonest majority, or guaranteed output delivery with honest majority). Compared to the state of the art, our protocol offers significant gains both in the adversary model (i.e., dishonest vs. honest majority) and practical performance: empirically, our online phase obtains approximately 20,000× better throughput, and up to a 37× improvement in latency. Image showing part 2 of abstract.
October 3, 2025 at 7:24 AM
Reposted by Chris Peikert
chrispeikert.bsky.social
We will Make this deadline, very strongly, because we are WINNERS—but Europe and the Rest of the world will have to pay up BIGLY with the strongest and Most polished Best Paper awards! That is the least these low IQ individuals can do to Pay back what we Americans so richly deserve!
October 3, 2025 at 3:37 AM
chrispeikert.bsky.social
Other countries in Europe are LAUGHING at us, with their “Midnight Anywhere on Earth” conference submission Deadlines!!

They’re finishing their papers and taking off for the Weekend at 2pm Friday, while we Americans have to pull ALL-NIGHTERS!

Not on my (your favorite PC chair) watch—MAGTBAARHA!
October 3, 2025 at 12:14 AM
Reposted by Chris Peikert
sorenspicknall.bsky.social
"Rodrick Johnson, 67, is one of many residents who were detained by federal agents during the South Shore raid. A U.S. citizen, he said agents broke through his door and dragged him out in zip ties."
Massive immigration raid on Chicago apartment building leaves residents reeling: 'I feel defeated'
The Department of Homeland Security said federal agents with Border Patrol, the FBI and the Bureau of Alcohol, Tobacco, Firearms and Explosives arrested 37 people in the raid.
chicago.suntimes.com
October 2, 2025 at 3:14 AM