--- title: Factoring "short-sleeve" RSA keys with polynomials description: Trail of Bits researchers discovered hundreds of weak RSA and DSA keys with heavily biased (zero-heavy) bits in the wild, dubbed 'short-sleeve' keys. They... canonical: https://daily.dev/posts/factoring-short-sleeve-rsa-keys-with-polynomials-u8ufoqxqq twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Factoring "short-sleeve" RSA keys with polynomials | daily.dev og:description: Trail of Bits researchers discovered hundreds of weak RSA and DSA keys with heavily biased (zero-heavy) bits in the wild, dubbed 'short-sleeve' keys. They... og:url: https://daily.dev/posts/factoring-short-sleeve-rsa-keys-with-polynomials-u8ufoqxqq og:image: https://api.daily.dev/og/posts/u8uFoqxQQ.png og:image:alt: Factoring "short-sleeve" RSA keys with polynomials og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Factoring "short-sleeve" RSA keys with polynomials **[Trail of Bits Blog](https://daily.dev/sources/trail-of-bits)** · 11 min read · 0 upvotes · 0 comments ## Summary Trail of Bits researchers discovered hundreds of weak RSA and DSA keys with heavily biased (zero-heavy) bits in the wild, dubbed 'short-sleeve' keys. They developed a novel polynomial-based cryptanalytic technique that reduces RSA factoring to the easier problem of polynomial factoring by exploiting the regular structure of zero-bit blocks in big-integer limbs. One pattern was traced to a type mismatch bug in CompleteFTP (EnterpriseDT) versions 10.0.0–12.0.0 for RSA and up to 23.0.4 for DSA, where Array.Copy implicitly cast 8-bit RNG output into 32-bit limbs, leaving most bits zero. The researchers recovered 603 unique RSA private keys and 74 DSA private keys from internet scans. CompleteFTP v26.1.0 now auto-detects vulnerable keys, and a standalone checker tool has been released. A second pattern affecting Yahoo and Verizon certificates remains unexplained. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Schneier on Security](https://daily.dev/posts/schneier-on-security-mpktnmwvf) · Schneier on Security · 0 upvotes · 0 comments - [I’ve factored the RSA keys of a Certificate Authority…from the 90s](https://daily.dev/posts/i-ve-factored-the-rsa-keys-of-a-certificate-authority-from-the-90s-5negnazgf) · Lobsters · 0 upvotes · 0 comments - [We found cryptography bugs in the elliptic library using Wycheproof](https://daily.dev/posts/we-found-cryptography-bugs-in-the-elliptic-library-using-wycheproof-togrvgscx) · Hacker News · 1 upvotes · 0 comments - [From a Silent Math Error to Certificate Bypass: Uncovering an Integer Overflow in a TLS Parser](https://daily.dev/posts/from-a-silent-math-error-to-certificate-bypass-uncovering-an-integer-overflow-in-a-tls-parser-dt1x6vmjr) · InfoSec Write-ups · 0 upvotes · 0 comments --- Tags: [#security](https://daily.dev/tags/security) [View this post on daily.dev](https://daily.dev/posts/factoring-short-sleeve-rsa-keys-with-polynomials-u8ufoqxqq) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Factoring \"short-sleeve\" RSA keys with polynomials","url":"https://daily.dev/posts/factoring-short-sleeve-rsa-keys-with-polynomials-u8ufoqxqq","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/factoring-short-sleeve-rsa-keys-with-polynomials-u8ufoqxqq"},"datePublished":"2026-06-12T11:13:04.472Z","dateModified":"2026-06-12T11:13:33.299Z","description":"Trail of Bits researchers discovered hundreds of weak RSA and DSA keys with heavily biased (zero-heavy) bits in the wild, dubbed 'short-sleeve' keys. 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