Solana developers have formally proposed removing durable nonces, the transaction feature that allows signed transactions to remain valid beyond the normal blockhash window. The proposal, SIMD-0723, was opened on November 5 and would require every transaction to use a recent blockhash while disabling System Program instructions for nonce accounts.
The change follows renewed scrutiny after durable nonces were used in the $270 million Drift exploit, although the draft itself does not cite Drift. Solana’s network now runs 200-millisecond slots, cutting normal blockhash validity to about 30 seconds. Durable nonces extend that window for use cases such as offline signing by custodians and exchanges, but Solana says the feature has also created security bugs, blocked asynchronous execution and attracted spam.
Under the deprecation plan, replacement functionality would move into on-chain programs rather than remain inside the runtime. The draft warns that failed execution may leave a signed authorization usable, meaning custodians could not treat an unsuccessful submission as automatic revocation. Fireblocks previously supported retiring durable nonces but raised concerns about large-scale migrations and whether smart-contract custody arrangements would satisfy institutional security policies.
Solana Foundation identifies Anza’s Programmatic Signer and Blueshift’s Vector as two replacement candidates, though neither has received a final designation. The proposal prohibits mainnet activation before May 5, 2027, and provides at least six months for affected operators to migrate after replacement software becomes ready. It remains an open pull request requiring technical approvals from both Anza and Firedancer engineers.
