Zilliqa Halts Native Transfers After a Seven-Year Ledger Flaw Lets Attackers Rebuild Private Keys

The layer-1 network Zilliqa has suspended native transactions after concluding that roughly five signatures produced by the same private key can be enough to reconstruct that key. The defect is not a smart-contract bug or a stolen seed phrase. It is a cryptographic implementation error inside the Ledger hardware-wallet app that signs Zilliqa's native (non-EVM) transactions.

The root cause is a biased signing nonce. For each signature the app generated 40 bytes of randomness, reduced the value modulo the secp256k1 curve order, then copied the wrong 32-byte window into the nonce. That mistake fixed the highest 64 bits of every nonce at zero, leaving each value below 2^192. Predictable structure in a signing nonce is the standard condition that lets an attacker apply lattice-reduction techniques and recover the underlying key. Zilliqa says every version of the app shipped between 2019 and 2026 carried the flaw, that it observed on-chain activity consistent with active exploitation on July 19, and that it confirmed the cause on July 21.

Speed now determines the outcome. Because a reconstructed key lets an attacker submit a competing transfer that executes before any ordinary rescue transaction, Zilliqa is building a migration path rather than telling users to simply move funds. The flaw was confined to the native signing path, and the exchange Upbit placed ZIL on a delisting review.