Offline Signing Tutorial

How to vote using eosc and an air gapped computer

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This step-by-step guide assumes you have a known account on mainnet (referred to as YOURACCOUNT), that is provisioned with the public key corresponding to the private key you’ll be using in this process.

1. [ONLINE COMPUTER] Download a version of eosc from https://github.com/eoscanada/eosc/releases targeting your Air Gapped Computer’s platform: Windows, Mac or Linux (a small footprint Linux distribution is preferred).

2. [ONLINE COMPUTER] Download and extract eosc for the Online Computer too.

3. [AIR GAPPED COMPUTER] Move the eosc distribution to your Air Gapped Computer and extract it over there.

4. [AIR GAPPED COMPUTER] Create a new Vault and punch in your private key(s):

eosc vault create --import --comment "Airtight wallet"

This will create a new eosc-vault.json file holding your key(s), encrypted with your passphrase, on the Air Gapped Computer’s disk.

1. [ONLINE COMPUTER] Prepare your voteproducer transaction with:

eosc vote producers YOURACCOUNT PRODUCER1 PRODUCER2 PRODUCER3... --write-transaction unsigned-tx.json --skip-sign --expiration 3600

This will create a file unsigned-tx.json containing the voteproducer action. It will not try to sign it (that will happen on the Air Gapped Computer) and sets an expiration of one hour for the roundtrip to happen.

You can check its unpacked data with eosc tx unpack unsigned-tx.json.

NOTE: you can use any eosc commands that produce transactions (like eosc transfer, eosc system delegatebw) in the same way.

1. [ONLINE COMPUTER] Copy the unsigned-tx.json file to your Air Gapped Computer by whatever means.

2. [AIR GAPPED COMPUTER] Sign the transaction by replacing PUBLIC_KEY by the Public Key that matches the private key in your Vault (and the YOURACCOUNT account authority):

eosc tx sign unsigned-tx.json --offline-sign-key PUBLIC_KEY..... --write-transaction signed-tx.json

This command will write signed-tx.json on disk.

1. [AIR GAPPED COMPUTER] Move the signed-tx.json back to the Online Computer.

2. [ONLINE COMPUTER] Push the signed transaction to the chain:

eosc tx push signed-tx.json

That’s it!

Troubleshooting

If the transaction failed for some reason, you can read the error message and see if they match one of:

• UnAuthorized errors: this means you have not signed the transaction with the keys required to authorize the actor@permission specified in the transaction’s actions.

• expired transaction: you need to do the whole loop within the timeframe of the original --expiration. If you give --expiration more than an hour, note that you can only submit the transaction to the chain in the last hour of expiration.

• Transaction's reference block did not match.: this means maybe you didn’t create the transaction from the same chain you’re trying to push it to.

• transaction bears irrelevant signatures from these keys: [\"EOS5J5....\"]: this means you didn’t need to sign with this key to authorize the actor@permission you specified in the transaction’s actions.

• some other assertion errors, which are normal errors that would have occurred if you tried to sign it online, investigate with the contract in question.