A 7 year Ledger bug lets attackers rebuild a private key from five signatures in seconds

Zilliqa has suspended native transactions after discovering that roughly five affected signatures from the same private key may provide enough information to reconstruct that key, creating a recovery problem that an ordinary transfer cannot safely solve.The vulnerability is confined to Schnorr signatures generated for native, non-EVM transactions through the Zilliqa Ledger app, according to the network’s security disclosure. Zilliqa said every version of the app released between 2019 and 2026 contained the flaw.Zilliqa said it detected on-chain activity consistent with active exploitation on July 19 and confirmed the root cause on July 21. The disclosure did not identify affected addresses or quantify any losses.Public signatures can expose the private keyThe flaw occurred while the Ledger app generated the ephemeral nonce required for each native Zilliqa signature. The signing routine generated 40 bytes of randomness and reduced the result modulo the secp256k1 curve order, but then copied the wrong 32-byte range into the nonce buffer.That operation retained eight zero-padding bytes while discarding eight bytes of actual entropy, fixing the nonce’s highest 64 bits at zero and leavi...