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Verify message signatures without creating a wallet instance. This is useful for readonly verification scenarios where you only have access to a Spark address.

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Use Case

When building applications that need to verify signatures but don’t have access to wallet credentials:
  • Readonly wallet views
  • Signature verification services
  • Cross-chain verification (verifying Spark signatures from other chains)
  • Server-side verification without sensitive key material

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How It Works

Spark addresses encode the wallet’s identity public key. You can extract this key using decodeSparkAddress and verify signatures directly with secp256k1.

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Implementation

import { decodeSparkAddress } from "@buildonspark/spark-sdk";
import * as secp256k1 from "@noble/secp256k1";

// Extract identity public key from Spark address
const { identityPublicKey } = decodeSparkAddress(address, network);

// Verify the signature
const isValid = secp256k1.verify(signature, message, identityPublicKey);

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Parameters

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address
string
required
The Spark address to extract the identity public key from
​
network
NetworkType
required
The network type (MAINNET, TESTNET, SIGNET, REGTEST, or LOCAL)
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signature
Uint8Array | string
required
The signature to verify
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message
Uint8Array | string
required
The original message that was signed

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Full Example

import { decodeSparkAddress } from "@buildonspark/spark-sdk";
import type { NetworkType } from "@buildonspark/spark-sdk";
import * as secp256k1 from "@noble/secp256k1";
import { sha256 } from "@noble/hashes/sha256";

async function verifySparkSignature(
  address: string,
  message: string,
  signature: string,
  network: NetworkType = "MAINNET"
): Promise<boolean> {
  // Decode address to get identity public key
  const { identityPublicKey } = decodeSparkAddress(address, network);

  // Hash the message (signatures are typically over message hashes)
  const messageHash = sha256(new TextEncoder().encode(message));

  // Convert signature from hex if needed
  const sigBytes = typeof signature === "string"
    ? Uint8Array.from(Buffer.from(signature, "hex"))
    : signature;

  // Verify using secp256k1
  return secp256k1.verify(sigBytes, messageHash, identityPublicKey);
}

// Usage
const isValid = await verifySparkSignature(
  "sp1qw508d6qejxtdg4y5r3zarvary0c5xw7k...",
  "Hello, Spark!",
  "304402..."
);
console.log("Signature valid:", isValid);

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Key Points

No Wallet Required

decodeSparkAddress is exported directly from the SDK and doesn’t require wallet initialization

Lightweight

Only needs the SDK and a secp256k1 library—no sensitive data or network calls