Offline Signing

The practice of signing a Solana transaction on an air-gapped or disconnected device and then broadcasting the signed transaction bytes from an online machine, used to protect private keys from network-exposed environments. Because standard Solana transactions embed a recent blockhash that expires in ~90 seconds, offline signing in practice requires durable nonces to give signers an unlimited preparation window. Offline signing is common in institutional custody, hardware wallet workflows, and high-security treasury management.