Skip to main content

Durable Transaction Nonces in the Openos CLI

Durable transaction nonces are a mechanism for getting around the typical short lifetime of a transaction's recent_blockhash. They are implemented as a Openos Program, the mechanics of which can be read about in the proposal.

Usage Examples​

Nonce Authority​

Authority over a nonce account can optionally be assigned to another account. In doing so the new authority inherits full control over the nonce account from the previous authority, including the account creator. This feature enables the creation of more complex account ownership arrangements and derived account addresses not associated with a keypair. The --nonce-authority <AUTHORITY_KEYPAIR> argument is used to specify this account and is supported by the following commands

  • create-nonce-account
  • new-nonce
  • withdraw-from-nonce-account
  • authorize-nonce-account

Nonce Account Creation​

The durable transaction nonce feature uses an account to store the next nonce value. Durable nonce accounts must be rent-exempt, so need to carry the minimum balance to achieve this.

A nonce account is created by first generating a new keypair, then create the account on chain

  • Command
openos-keygen new -o nonce-keypair.json
openos create-nonce-account nonce-keypair.json 1
  • Output
2SymGjGV4ksPdpbaqWFiDoBz8okvtiik4KE9cnMQgRHrRLySSdZ6jrEcpPifW4xUpp4z66XM9d9wM48sA7peG2XL

To keep the keypair entirely offline, use the Paper Wallet keypair generation instructions instead

Querying the Stored Nonce Value​

Creating a durable nonce transaction requires passing the stored nonce value as the value to the --blockhash argument upon signing and submission. Obtain the presently stored nonce value with

  • Command
openos nonce nonce-keypair.json
  • Output
8GRipryfxcsxN8mAGjy8zbFo9ezaUsh47TsPzmZbuytU

Advancing the Stored Nonce Value​

While not typically needed outside a more useful transaction, the stored nonce value can be advanced by

  • Command
openos new-nonce nonce-keypair.json
  • Output
44jYe1yPKrjuYDmoFTdgPjg8LFpYyh1PFKJqm5SC1PiSyAL8iw1bhadcAX1SL7KDmREEkmHpYvreKoNv6fZgfvUK

Display Nonce Account​

Inspect a nonce account in a more human friendly format with

  • Command
openos nonce-account nonce-keypair.json
  • Output
balance: 0.5 BTG
minimum balance required: 0.00136416 BTG
nonce: DZar6t2EaCFQTbUP4DHKwZ1wT8gCPW2aRfkVWhydkBvS

Withdraw Funds from a Nonce Account​

Withdraw funds from a nonce account with

  • Command
openos withdraw-from-nonce-account nonce-keypair.json ~/.config/openos/id.json 0.5
  • Output
3foNy1SBqwXSsfSfTdmYKDuhnVheRnKXpoPySiUDBVeDEs6iMVokgqm7AqfTjbk7QBE8mqomvMUMNQhtdMvFLide

Close a nonce account by withdrawing the full balance

Assign a New Authority to a Nonce Account​

Reassign the authority of a nonce account after creation with

  • Command
openos authorize-nonce-account nonce-keypair.json nonce-authority.json
  • Output
3F9cg4zN9wHxLGx4c3cUKmqpej4oa67QbALmChsJbfxTgTffRiL3iUehVhR9wQmWgPua66jPuAYeL1K2pYYjbNoT

Other Commands Supporting Durable Nonces​

To make use of durable nonces with other CLI subcommands, two arguments must be supported.

  • --nonce, specifies the account storing the nonce value
  • --nonce-authority, specifies an optional nonce authority

Example Pay Using Durable Nonce​

Here we demonstrate Alice paying Bob 1 BTG using a durable nonce. The procedure is the same for all subcommands supporting durable nonces

- Create accounts​

First we need some accounts for Alice, Alice's nonce and Bob

$ openos-keygen new -o alice.json
$ openos-keygen new -o nonce.json
$ openos-keygen new -o bob.json

- Fund Alice's account​

Alice will need some funds to create a nonce account and send to Bob. Airdrop her some BTG

$ openos airdrop -k alice.json 1
1 BTG

- Create Alice's nonce account​

Now Alice needs a nonce account. Create one

Here, no separate nonce authority is employed, so alice.json has full authority over the nonce account

$ openos create-nonce-account -k alice.json nonce.json 0.1
3KPZr96BTsL3hqera9up82KAU462Gz31xjqJ6eHUAjF935Yf8i1kmfEbo6SVbNaACKE5z6gySrNjVRvmS8DcPuwV

- A failed first attempt to pay Bob​

Alice attempts to pay Bob, but takes too long to sign. The specified blockhash expires and the transaction fails

$ openos transfer -k alice.json --blockhash expiredDTaxfagttWjQweib42b6ZHADSx94Tw8gHx11 bob.json 0.01
[2020-01-02T18:48:28.462911000Z ERROR openos_cli::cli] Io(Custom { kind: Other, error: "Transaction \"33gQQaoPc9jWePMvDAeyJpcnSPiGUAdtVg8zREWv4GiKjkcGNufgpcbFyRKRrA25NkgjZySEeKue5rawyeH5TzsV\" failed: None" })
Error: Io(Custom { kind: Other, error: "Transaction \"33gQQaoPc9jWePMvDAeyJpcnSPiGUAdtVg8zREWv4GiKjkcGNufgpcbFyRKRrA25NkgjZySEeKue5rawyeH5TzsV\" failed: None" })

- Nonce to the rescue!​

Alice retries the transaction, this time specifying her nonce account and the blockhash stored there

Remember, alice.json is the nonce authority in this example

$ openos nonce-account nonce.json
balance: 0.1 BTG
minimum balance required: 0.00136416 BTG
nonce: F7vmkY3DTaxfagttWjQweib42b6ZHADSx94Tw8gHx3W7
$ openos transfer -k alice.json --blockhash F7vmkY3DTaxfagttWjQweib42b6ZHADSx94Tw8gHx3W7 --nonce nonce.json bob.json 0.01
HR1368UKHVZyenmH7yVz5sBAijV6XAPeWbEiXEGVYQorRMcoijeNAbzZqEZiH8cDB8tk65ckqeegFjK8dHwNFgQ

- Success!​

The transaction succeeds! Bob receives 0.01 BTG from Alice and Alice's stored nonce advances to a new value

$ openos balance -k bob.json
0.01 BTG
$ openos nonce-account nonce.json
balance: 0.1 BTG
minimum balance required: 0.00136416 BTG
nonce: 6bjroqDcZgTv6Vavhqf81oBHTv3aMnX19UTB51YhAZnN