Private key

A signing key must remain secret. Its related public key verifies signatures without exposing the secret. Ethereum externally owned accounts normally use ECDSA over secp256k1. Other networks and accounts may use different algorithms.

One key may control a simple account, while a multisignature account requires several approvals. Contracts can restrict a key’s actions or allow its replacement.

Losing a key does not always mean permanently losing an account: backups, social recovery or signer rotation may exist. A compromised key requires assessment of all associated permissions.