Durable Nonces Caused Solana Blockchain Halt

On Jun 1, 2022, Solana Blockchain halted due to an outage. Solana Lab’s Chief Communication Officer Austin Federa said that validators could only restart the network only after disabling the “durable nonce transactions”. The blockchain was down for almost four hours.

What is Durable Nonce?

In cryptography, a nonce is a random number used for a specific purpose, which in Solana’s case is to sign transactions.

Most of these transactions are marked instantly with a nonce value. However, some transactions need multiple signatures to sign transactions. Signing with multiple signatures (with multiple wallets) takes time and won’t be possible within one block time.

Durable nonces are used to sign these multi-signature transactions that use a longer time. Hence, the name durable nonce.

Why did Solana Blockchain halt?

Solana Blockchain had a bug in the durable nonces method that caused the blockchain to halt. The blockchain failed to handle durable nonces on Wed 1 Jun 2022. Instead of treating these inbound transactions as one single transaction, the network’s validators counted them as two separate transactions.

This bug was reportedly known earlier and was being fixed but this time it behaved in an unexpected manner. The following tweet was from Laine from Stakewiz, a Solana Validator.

Solana halt today, what happened?

A bug relating to durable nonces was triggered on a majority of validators, leading to a block hash mismatch & validators stalling.

This was actually a known bug that was being fixed and hadn't been triggered in this form previously.

— Laine ❤️ stakewiz.com (@laine_sa_) June 1, 2022

What does this mean for me?

Blockchain halts won’t