Schneier - Recovering Public Keys from Signatures

Interesting summary of various ways to derive the public key from digitally signed files.

Normally, with a signature scheme, you have the public key and want to know whether a given signature is valid. But what if we instead have a message and a signature, assume the signature is valid, and want to know which public key signed it? A rather delightful property if you want to attack anonymity in some proposed “everybody just uses cryptographic signatures for everything” scheme.



from Schneier on Security https://www.schneier.com/blog/archives/2024/06/recovering-public-keys-from-signatures.html

Comments

Post a Comment

Popular posts from this blog

Krebs - NY Charges First American Financial for Massive Data Leak

Image
In May 2019, KrebsOnSecurity broke the news that the website of mortgage title insurance giant First American Financial Corp. had exposed approximately 885 million records related to mortgage deals going back to 2003. On Wednesday, regulators in New York announced that First American was the target of their first ever cybersecurity enforcement action in connection with the incident, charges that could bring steep financial penalties. First American Financial Corp. Santa Ana, Calif.-based  First American [ NYSE:FAF ] is a leading provider of title insurance and settlement services to the real estate and mortgage industries. It employs some 18,000 people and brought in $6.2 billion in 2019 . As first reported here last year , First American’s website exposed 16 years worth of digitized mortgage title insurance records — including bank account numbers and statements, mortgage and tax records, Social Security numbers, wire transaction receipts, and drivers license images. The d...
Read more

KnowBe4 - Scam Of The Week: "When Users Add Their Names to a Wall of Shame"

Image
Eric Howes , KnowBe4 Principal Lab Researcher, found out about another insidious bad guy trick: " If you work in IT there has undoubtedly come a dark moment when you wondered to yourself just who among your employee users would be gullible enough to click through a phishing email and potentially bring down your organization. from KnowBe4 Security Awareness Training Blog https://blog.knowbe4.com/when-users-add-their-names-to-a-wall-of-shame
Read more