wallet: add sign-msg and verify-msg commands (WalletConnect scheme) by Copilot · Pull Request #4188 · nspcc-dev/neo-go

Copilot · 2026-03-10T10:30:11Z

NeoGo had no way to produce or verify message signatures compatible with Neon/NeoLine and the NeoFS WalletConnect scheme, making it impossible to interoperate with signatures from other Neo wallets.

Changes

pkg/crypto/keys/walletconnect.go — core primitives:
- (*PrivateKey).SignWalletConnect(data []byte) ([]byte, error) — signs using the WalletConnect scheme; returns 80 bytes (64-byte ECDSA sig + 16-byte random salt)
- (*PublicKey).VerifyWalletConnect(data, signature []byte) bool — verifies an 80-byte WalletConnect signature
- Hash computed by streaming the canonical payload directly into sha256.New() (no intermediate buffer): 0x01 0x00 0x01 0xf0 | VarUint(len(hex(salt)+base64(msg))) | hex(salt) | base64(msg) | 0x00 0x00
cli/wallet/message.go — two new wallet subcommands:
- wallet sign-msg — signs an arbitrary message and prints the hex-encoded 80-byte signature (64-byte ECDSA + 16-byte salt)
- wallet verify-msg — verifies against a public key or wallet address

Usage

# Sign (cleartext, hex, or base64 input)
neo-go wallet sign-msg -w wallet.json -a NfgHwwTi3wHAS8aFAN243C5vGbkYDpqLHP "Hello, Neo"
# Output:
deadbeef...a1b2c3d4e5f6...  # 80 bytes hex: 64-byte ECDSA sig + 16-byte salt

# Verify (no wallet needed if public key is known)
neo-go wallet verify-msg \
  --public-key 03... \
  --signature deadbeef...a1b2c3d4e5f6... \
  "Hello, Neo"

Both commands accept --hex and --base64 flags to handle binary messages. verify-msg also accepts --address with a wallet for address-based lookup, extracting the public key from the verification script without requiring private key decryption.

The signing payload format is identical to the neofs-sdk-go SignerWalletConnect implementation, ensuring cross-wallet compatibility.

Original prompt

This section details on the original issue you should resolve

<issue_title>wallet sign-msg</issue_title>
<issue_description>## Is your feature request related to a problem? Please describe.
I'm always frustrated when I can't reproduce signatures routinely made by Neon/Neoline/etc in NeoGo.

Describe the solution you'd like

Add some way (wallet sign-msg command or something else) to produce signatures like in NeoFS "WalletConnect" scheme that is widely known for years and available in various wallets. The message can be cleartext or hex/base64, wallet shouldn't encode it.

Describe alternatives you've considered

No alternatives, some compatible thing has to exist.

Additional context

https://pkg.go.dev/github.com/nspcc-dev/neofs-sdk-go@v1.0.0-rc.16/crypto/ecdsa#SignerWalletConnect
neo-project/neo#4286
neo-project/neo-node#924
neo-project/proposals#213
neo-project/proposals#210
</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes wallet sign-msg #4110

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

…g scheme Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

…word in test Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

codecov · 2026-03-10T11:38:29Z

Codecov Report

❌ Patch coverage is 73.28767% with 39 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.35%. Comparing base (88586b7) to head (fd9a1fd).

Files with missing lines	Patch %	Lines
cli/wallet/message.go	61.05%	24 Missing and 13 partials ⚠️
pkg/crypto/keys/walletconnect.go	93.93%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4188      +/-   ##
==========================================
- Coverage   83.40%   83.35%   -0.06%     
==========================================
  Files         357      359       +2     
  Lines       43760    43906     +146     
==========================================
+ Hits        36499    36598      +99     
- Misses       5464     5496      +32     
- Partials     1797     1812      +15

☔ View full report in Codecov by Sentry.
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roman-khimov · 2026-03-11T14:11:05Z

+// RFC 6979 ECDSA with SHA-256. The returned signature is 64 bytes of ECDSA
+// signature followed by WalletConnectSaltLen bytes of salt (80 bytes total).
+func (p *PrivateKey) SignWalletConnect(data []byte) ([]byte, error) {
+	b64 := make([]byte, base64.StdEncoding.EncodedLen(len(data)))


Avoid this and other allocations, we only need a hash of this data, so io.Writer of hash.Hash can be leveraged to avoid buffering and copying things around.

Fixed in commit 3681226. Replaced the intermediate payload buffer with a streaming approach: sha256.New() is used as an io.Writer, and hex.NewEncoder/base64.NewEncoder write directly into the hash — no buffer allocation needed.

roman-khimov · 2026-03-11T14:12:00Z

+		return false
+	}
+	b64 := make([]byte, base64.StdEncoding.EncodedLen(len(data)))
+	base64.StdEncoding.Encode(b64, data)


roman-khimov · 2026-03-11T14:14:36Z

+	"github.com/urfave/cli/v2"
+)
+
+// signMessageResult contains the output of the sign-msg command.


Not needed. The output is just a signature.

Removed in commit 3681226. sign-msg now just prints the hex-encoded 80-byte signature (ECDSA + salt) directly.

roman-khimov · 2026-03-11T14:14:50Z

+	}
+
+	sig := sigWithSalt[:keys.SignatureLen]
+	salt := sigWithSalt[keys.SignatureLen:]


Why splitting it?

Fixed in commit 3681226. No longer splitting — SignWalletConnect returns the full 80-byte combined value which is passed directly to output/verify without intermediate slicing.

roman-khimov · 2026-03-11T14:15:39Z

+		return cli.Exit(err, 1)
+	}
+
+	saltHex := ctx.String("salt")


Single parameter, please.

Fixed in commit 3681226. Removed the --salt flag entirely. --signature now takes the full 80-byte hex value (64-byte ECDSA + 16-byte salt) as produced by sign-msg.

roman-khimov · 2026-03-11T14:19:27Z

@copilot, please fix comments from previous review

Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

roman-khimov · 2026-03-11T14:43:51Z

@copilot try again

…ature param Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

…test Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Copilot · 2026-03-11T14:54:27Z

@copilot try again

Done in fc96671. All review feedback addressed: streaming hash (no allocation), plain hex signature output, single --signature parameter combining ECDSA bytes and salt.

Initial plan

ca3d241

Copilot AI assigned Copilot and roman-khimov Mar 10, 2026

Copilot started work on behalf of roman-khimov March 10, 2026 10:30 View session

Copilot AI and others added 2 commits March 10, 2026 10:49

Add wallet sign-msg and verify-msg commands with WalletConnect signin…

9b69d8c

…g scheme Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Fix code review feedback: JSON formatting and remove unnecessary pass…

fd9a1fd

…word in test Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Copilot AI changed the title ~~[WIP] Add wallet sign-msg command for signature production~~ wallet: add sign-msg and verify-msg commands (WalletConnect scheme) Mar 10, 2026

Copilot finished work on behalf of roman-khimov March 10, 2026 10:56

roman-khimov reviewed Mar 11, 2026

View reviewed changes

Copilot started work on behalf of roman-khimov March 11, 2026 14:19 View session

Changes before error encountered

195c3f6

Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Copilot started work on behalf of roman-khimov March 11, 2026 14:44 View session

Copilot AI and others added 2 commits March 11, 2026 14:50

Address review feedback: stream hash, plain sig output, single --sign…

3681226

…ature param Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Use base64.StdEncoding.EncodeToString instead of hardcoded string in …

fc96671

…test Co-authored-by: roman-khimov <22092804+roman-khimov@users.noreply.github.com>

Copilot finished work on behalf of roman-khimov March 11, 2026 14:55

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