ECDSA Weakness Where Nonces Are Reused

Prof Bill Buchanan OBE FRSE
3 min readJan 22, 2021

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It is a well-known secret that ECDSA needs to be set up properly, else the private key could be revealed. In the worse case, Eve could reveal Alice’s Bitcoin private key from the ECDSA signatures. One of the weaknesses is where the same nonce value is used for different messages. So let’s crack.

With an ECDSA signature, we sign a message with a private key (priv) and prove the signature with the…

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Prof Bill Buchanan OBE FRSE

Professor of Cryptography. Serial innovator. Believer in fairness, justice & freedom. Based in Edinburgh. Old World Breaker. New World Creator. Building trust.