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Received β€” 8 June 2026 ⏭ Schneier on Security

Critical Zcash Vulnerability Found and Fixed

8 June 2026 at 19:06

If you’re a userβ€”owner?β€”of this cryptocurrency, this is important:

On May 29, the security researcher Taylor Hornby found a critical vulnerability in Zcash Orchard privacy pool using Claude Opus 4.8. The Zcash team hired Hornby specifically to look for this kind of issue. He found one fast enough to be embarrassing.

The Orchard pool is the newest and most advanced shielded transaction system in the cryptocurrency Zcash. Introduced in 2022, it allows users to send and receive ZEC while keeping transaction details private. It uses zero-knowledge proofs to validate transactions without revealing amounts or participants. The bug: a specific check that was supposed to validate transaction inputs wasn’t actually enforcing the rules it appeared to enforce. An attacker could have exploited the flaw to feed false inputs into that check and generate ZEC from nothing, with the zero-knowledge proof system blessing the fraudulent transaction as valid.

It’s fixed; that’s the good news. The bad news is that there’s no way of knowing if anyone exploited the vulnerability to steal money. And this fragility is the fundamental problem that makes blockchain such a bad idea.

Received β€” 23 April 2026 ⏭ Schneier on Security

Is β€œSatoshi Nakamoto” Really Adam Back?

20 April 2026 at 13:07

The New York Times has a long article where the author lays out an impressive array of circumstantial evidence that the inventor of Bitcoin is the cypherpunk Adam Back.

I don’t know. The article is convincing, but it’s written to be convincing.

I can’t remember if I ever met Adam. I was a member of the Cypherpunks mailing list for a while, but I was never really an active participant. I spent more time on the Usenet newsgroup sci.crypt. I knew a bunch of the Cypherpunks, though, from various conferences around the world at the time. I really have no opinion about who Satoshi Nakamoto really is.

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