Signing

Once you've instantiated your wallet in an unlocked state using one of the previously discussed methods, you can sign a message with wallet.sign_message. Below is a full example of how to sign and recover a message.

        let mut rng = StdRng::seed_from_u64(2322u64);
        let mut secret_seed = [0u8; 32];
        rng.fill_bytes(&mut secret_seed);

        let secret = secret_seed
            .as_slice()
            .try_into()
            .expect("The seed size is valid");

        // Create a wallet using the private key created above.
        let wallet = WalletUnlocked::new_from_private_key(secret, None);

        let message = "my message";

        let signature = wallet.sign_message(message).await?;

        // Check if signature is what we expect it to be
        assert_eq!(signature, Signature::from_str("0x8eeb238db1adea4152644f1cd827b552dfa9ab3f4939718bb45ca476d167c6512a656f4d4c7356bfb9561b14448c230c6e7e4bd781df5ee9e5999faa6495163d")?);

        // Recover address that signed the message
        let message = Message::new(message);
        let recovered_address = signature.recover(&message)?;

        assert_eq!(wallet.address().hash(), recovered_address.hash());

        // Verify signature
        signature.verify(&recovered_address, &message)?;
        Ok(())

You can also sign a transaction by using wallet.sign_transaction. Below is a full example of how to sign and recover a transaction.

        let secret = SecretKey::from_str(
            "5f70feeff1f229e4a95e1056e8b4d80d0b24b565674860cc213bdb07127ce1b1",
        )?;
        let mut wallet = WalletUnlocked::new_from_private_key(secret, None);

        // Set up a dummy transaction.
        let input_coin = Input::coin_signed(
            UtxoId::new(Bytes32::zeroed(), 0),
            Address::from_str(
                "0xf1e92c42b90934aa6372e30bc568a326f6e66a1a0288595e6e3fbd392a4f3e6e",
            )?,
            10000000,
            AssetId::from([0u8; 32]),
            TxPointer::default(),
            0,
            0u32.into(),
        );

        let output_coin = Output::coin(
            Address::from_str(
                "0xc7862855b418ba8f58878db434b21053a61a2025209889cc115989e8040ff077",
            )?,
            1,
            AssetId::from([0u8; 32]),
        );

        let mut tx: ScriptTransaction = FuelTransaction::script(
            0,
            1000000,
            0u32.into(),
            hex::decode("24400000")?,
            vec![],
            vec![input_coin],
            vec![output_coin],
            vec![],
        )
        .into();

        // Sign the transaction.
        let consensus_parameters = ConsensusParameters::default();
        let test_provider = Provider::new(FuelClient::new("test")?, consensus_parameters);
        wallet.set_provider(test_provider);
        let signature = wallet.sign_transaction(&mut tx)?;
        let message = Message::from_bytes(*tx.id(&consensus_parameters));

        // Check if signature is what we expect it to be
        assert_eq!(signature, Signature::from_str("8d2d7f8d5190d9acdc07717e39173bdfb0024b1c06e70b084994440eb9bdff17e57dfdcb6b45bd36a896566054809a21dfd67c0a25344c73cf9c4d9d6a32be05")?);

        // Recover address that signed the transaction
        let recovered_address = signature.recover(&message)?;

        assert_eq!(wallet.address().hash(), recovered_address.hash());

        // Verify signature
        signature.verify(&recovered_address, &message)?;
        Ok(())