Interesting scenario. The thing that comes to my mind immediately when hearing "Schnorr" and "attack" is the Sony-hack that is based on accidentally choosing the same r-value more than once. Which is a very famous attack in crypto
Small correction: the sony-hack was with k-value in DSA, not r-value in Schnorr. But the two hacks are conceptually the same
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Half the same key certainly narrows down the search :D The effective bits of security for this are 64, which is still better than SSL 20 years ago.
wait. DSA. not ECDSA.
The noughties were miserable times after 2005 until the end of the decade.
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