Adds message signing to wallet #4286

adrian-fjellberg · 2025-11-07T12:14:58Z

Adds the ability to sign arbitrary messages using wallet accounts. The user can specify the elliptic curve to use for signing (secp256r1 or secp256k1). It generates a payload using salt and the provided message, then signs the payload with each available wallet account, displaying the address, public key, salt and signature.

Description

This PR introduces a new sign_message command to the Neo CLI, enabling message signing outside of transactions.
Previously, the CLI only supported signing serialized transaction data, which made it impossible to produce verifiable message signatures for use in external applications, authentication workflows, or dApp integrations.

With this change, users can now easily sign and verify arbitrary messages directly from their local wallet.

Change Log

Added the "sign_message" command to the Neo CLI.
Changed Neo.CLI.MainService to implement the "sign_message" command.
Added optional curve parameter (supports secp256r1 and secp256k1)
Implemented payload creation using salt + message for improved uniqueness

Fixes #4285

Type of change

Optimization (the change is only an optimization)
Style (the change is only a code style for better maintenance or standard purpose)
Bug fix (non-breaking change which fixes an issue)
New feature (non-breaking change which adds functionality)
Breaking change (fix or feature that would cause existing functionality to not work as expected)
This change requires a documentation update

How Has This Been Tested?

Unit Testing
Run Application: manually tested sign_message on local CLI with both curves
Local Computer Tests
No Testing

Checklist:

My code follows the style guidelines of this project
I have performed a self-review of my code
I have commented my code, particularly in hard-to-understand areas
I have made corresponding changes to the documentation
My changes generate no new warnings
I have added tests that prove my fix is effective or that my feature works
New and existing unit tests pass locally with my changes
Any dependent changes have been merged and published in downstream modules

Adds the ability to sign arbitrary messages using wallet accounts. The user can specify the elliptic curve to use for signing (secp256r1 or secp256k1). It generates a payload using salt and the provided message, then signs the payload with each available wallet account, displaying the address, public key, salt and signature.

src/Neo.CLI/CLI/MainService.Wallet.cs

Jim8y · 2025-11-08T01:00:55Z

src/Neo.CLI/CLI/MainService.Wallet.cs

+                var signature = Crypto.Sign(payload, key.PrivateKey, selectedCurve);
+
+                ConsoleHelper.Info("Address: ", account.Address);
+                ConsoleHelper.Info("  PublicKey: ", key.PublicKey.EncodePoint(true).ToHexString());


we dont really support secp256k1, the key you get is still p-256 pubkey.

Ok. I think I saw in the code for Crypto.Sign that both were supported so that is why I added it.

Do you want me tor remove the option to select curve and only use secp256r1?

We need a structured format that specifies the address, public key, and algorithm for signing. This also facilitates verification.

Some questions:

Should we require the user specifiy either the public key or address for signing?

If yes to question 1: If there is only one address in the open wallet, could we default to using this one? I think this will make signing more user friendly.

For specifing the algorithim, do you mean the curve or padding, salt, etc.? Or both?

Can we provide defaults for each option so that the command become user friendly?

I mean we need to define an output format including address, public key, and algorithm of the signature.

Latest commit includes the algorithm and curve used + some helpful text and link to documentation on how to verify the generated signatures.

@erikzhang, is this what you wanted?

Or did you want a stuctured format in terms of JSON or YAML?

Or did you want us to define a standard for the padding and salting?

I want a standard with json format please.

@erikzhang I made a draft: neo-project/proposals#210

Jim8y · 2025-11-08T01:27:46Z

src/Neo.CLI/CLI/MainService.Wallet.cs

+                w.Write((byte)0x01);
+                w.Write((byte)0x00);
+                w.Write((byte)0x01);
+                w.Write((byte)0xF0);
+                w.WriteVarBytes(paramBytes);
+                w.Write((ushort)0);
+                w.Flush();


what is the meaning of this script, some standard?

Yes, could you clarify it @adrian-fjellberg

It is to ensure that the message is not also a valid NEO transaction. I do not think it is a defined standard but it is the way both NEON wallet and NeoLine signs messages.

Do you want me to add comments to the code to clearify?

I see, its just some prefix.

I can add comments to the code.

Comments added in the latest commit.

adrian-fjellberg · 2025-11-08T12:07:23Z

I also started on documenting the command line feature:
https://github.com/adrian-fjellberg/neo-dev-portal/blob/feature/sign-message-cli-docs/docs/n3/node/cli/cli.md#sign_message

Refactors the `sign message` command to: - allow only signing only using the secp256r1 curve. - output the algorithm used to create the payload - output guide on how to verify the signed message Renames the `sign` command to `sign transaction` to avoid ambiguous calls with the new `sign message` command. Refactors the `OnCommand` method on the ConsoleServiceBase class so that parsing of arguments are differed to later in the execution. This is to solve an issue that occurs when ambiguous calls occur, one method might output errors in when parsing of arguments.

…message-sign' into feature/cli-arbitrary-message-sign

Wi1l-B0t · 2025-11-10T12:55:39Z

src/Neo.CLI/CLI/MainService.Wallet.cs

-        /// <param name="jsonObjectToSign">Json object to sign</param>
-        [ConsoleCommand("sign", Category = "Wallet Commands")]
+        /// <param name="jsonObjectToSign">The json string that records the transaction information</param>
+        [ConsoleCommand("sign transaction", Category = "Wallet Commands")]


sign tx is shorter.

Agreed. Fixed 👍

superboyiii · 2025-11-11T02:58:12Z

Is this armed for Neo4 or next release? @adrian-fjellberg

superboyiii · 2025-11-11T03:06:07Z

master is now only for Neo N4, master-n3 is for N3, dev is for N3 dev. So I guess you want to merge it into next release. It's better to change to dev. @adrian-fjellberg

erikzhang · 2025-11-11T03:28:47Z

dev is not used anymore.

adrian-fjellberg · 2025-11-11T10:03:41Z

master is now only for Neo N4, master-n3 is for N3, dev is for N3 dev. So I guess you want to merge it into next release. It's better to change to dev. @adrian-fjellberg

As fast as possilbe beacuse it will be important for nodes to be able to do offline signing in a secure way to claim candidate roles in the new Goevernance platform set to be released soon.

So I should change to master-n3 as per @erikzhang comment then?

shargon · 2025-11-11T10:07:55Z

src/Neo.CLI/CLI/MainService.Wallet.cs

+            using (var w = new BinaryWriter(ms, Encoding.UTF8, true))
+            {
+                // We add these 4 bytes to prevent the signature from being a valid transaction
+                w.Write((byte)0x01);


I would like to follow something like the https://www.cyfrin.io/blog/understanding-ethereum-signature-standards-eip-191-eip-712, domain separator it's important to avoid signature replays between different chains, like testnet and mainnet

neo/src/Neo/Network/P2P/Helper.cs

Lines 71 to 88 in ac7ebab

public static byte[] GetSignData(this IVerifiable verifiable, uint network)

{

/* Same as:

using MemoryStream ms = new();

using BinaryWriter writer = new(ms);

writer.Write(network);

writer.Write(verifiable.Hash);

writer.Flush();

return ms.ToArray();

*/

var buffer = new byte[SignDataLength];

BinaryPrimitives.WriteUInt32LittleEndian(buffer, network);

verifiable.Hash.Serialize(buffer.AsSpan(sizeof(uint)));

return buffer;

}

@adrian-fjellberg we should call this method, let me add some changes. Also this PR should be moved now to https://github.com/neo-project/neo-node

adrian-fjellberg · 2025-11-11T11:35:23Z

I only need the posibilty for nodes to sign an arbitrary message... We get 100% value from the current implementation. It satisfies all the needs of the reason behind the proposed change.

The value is:

Nodes get to claim their seat in the new Governance platform.
New canidates now have a way to sign messages when they are registering from the CLI rather from a wallet.

Wi1l-B0t reviewed Nov 7, 2025

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src/Neo.CLI/CLI/MainService.Wallet.cs Outdated Show resolved Hide resolved

Jim8y reviewed Nov 8, 2025

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Adrian Fjellberg and others added 4 commits November 8, 2025 14:57

Add comment about padding for the "sign_message" command

642cc9e

Merge branch 'master' into feature/cli-arbitrary-message-sign

3bca0e3

Merge remote-tracking branch 'adrian-fjellberg/feature/cli-arbitrary-…

7ccfbbf

…message-sign' into feature/cli-arbitrary-message-sign

Wi1l-B0t reviewed Nov 10, 2025

View reviewed changes

Wi1l-B0t and others added 2 commits November 10, 2025 20:57

Merge branch 'master' into feature/cli-arbitrary-message-sign

211b2b1

Renamed CLI command "sign transaction" to "sign tx"

bdc9a28

shargon reviewed Nov 11, 2025

View reviewed changes

adrian-fjellberg mentioned this pull request Nov 11, 2025

NEP: Standard for Offline Message Signing and Verification neo-project/proposals#210

Open

shargon mentioned this pull request Nov 11, 2025

Add GetSignData with only UInt256 type #4299

Merged

18 tasks

	public static byte[] GetSignData(this IVerifiable verifiable, uint network)
	{
	/* Same as:
	using MemoryStream ms = new();
	using BinaryWriter writer = new(ms);
	writer.Write(network);
	writer.Write(verifiable.Hash);
	writer.Flush();
	return ms.ToArray();
	*/

	var buffer = new byte[SignDataLength];

	BinaryPrimitives.WriteUInt32LittleEndian(buffer, network);
	verifiable.Hash.Serialize(buffer.AsSpan(sizeof(uint)));

	return buffer;
	}

Adds message signing to wallet #4286

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Adds message signing to wallet #4286

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adrian-fjellberg commented Nov 7, 2025

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