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How to verify a Self-Hosted Wallet with Digital Signature

  • Updated

CoinJar will never ask for your private key or seed phrase

Message signing only uses the message and the resulting signature. CoinJar will never ask for your private key, seed phrase, or recovery words.

How it works

CoinJar generates a unique message that includes your account, the address you're verifying, and a one-time code (a nonce). You sign that message in your wallet, then paste the signature back into CoinJar. Because the signature can only be produced by the private key for that address, a valid signature proves you own the wallet. The private key itself never leaves your device.

Supported Networks

Currently on CoinJar, the Digital Signature method supports the following networks:

  • Arbitrum
  • Avalanche C Chain
  • Bitcoin
  • Cardano
  • Dogecoin
  • Ethereum Classic
  • Ethereum
  • Litecoin
  • Optimism
  • Polygon
  • Solana

For any other networks, please verify your self-hosted wallet through the available methods such as Satoshi Test or Manual Upload. 

Step 1: Start wallet verification in CoinJar

  1. Sign in to your CoinJar account and navigate to More > Address Book.
  2. To start, click on the "+ Add Address" button.
  3. Enter the cryptocurrency address you want to verify along with the other required fields.
  4. Select Digital Signature as your verification method.
  5. CoinJar will display a unique message containing your address and a one-time nonce. Copy it exactly and do not change any characters, spaces, or line breaks.

Step 2: Sign the message with your wallet

The exact steps depend on how you intend sign your message, either via a web service or a wallet application.

Using a Web Service

Etherscan (Ethereum only)

Etherscan can only be used to sign messages on the Ethereum network.

  1. Visit Etherscan, then go to More → Services → Verified Signature.
  2. Choose Sign Message at the top right of the page.
  3. When prompted, connect your wallet via MetaMask or WalletConnect. WalletConnect lets you use other compatible wallets, such as Coinbase Wallet or Rainbow.
  4. Paste the exact, unique message provided by CoinJar into the Message field.
  5. Select Sign Message and confirm in your wallet.
  6. Copy the resulting signature hash.

You don't need to publish the signed message when Etherscan offers the option.

Solscan (Solana only)

Solscan can only be used to sign messages on the Solana network.

  1. Visit Solscan, then go to Resource → Verified Signature.
  2. Choose Sign Message at the top right of the page.
  3. When prompted, connect your wallet via Phantom, MetaMask or Ledger Wallet.
  4. Paste the exact, unique message provided by CoinJar into the Message field.
  5. Select Sign and confirm in your wallet.
  6. Copy the resulting signature hash.

You don't need to publish the signed message when Solscan offers the option.

Using a Wallet Application

Metamask (Ethereum and EVM chains)

  1. Open MetaMask and select the account that holds the address you're confirming.
  2. Open the signing feature. For a standalone signature, use a trusted signing page (such as Etherscan's Sign Message tool above) and connect MetaMask, or sign through the verification request you were directed to.
  3. Paste the exact, unique message from CoinJar.
  4. Select Sign and review the message in the MetaMask prompt.
  5. Confirm, then copy the resulting signature hash.

Ledger (Hardware wallet)

Ledger Live doesn't support message signing. To sign with your Ledger device, pair it with a compatible software wallet:

  • Ethereum and EVM chains (most common): use MetaMask connected to your Ledger.
  • Bitcoin: use Electrum connected to your Ledger.

Using Ledger with MetaMask (Ethereum and EVM chains)

  1. Connect your Ledger to MetaMask and select the account containing the address.
  2. Follow the MetaMask steps above to open the sign-message feature and paste the message.
  3. When you select Sign, MetaMask will prompt you to confirm on your Ledger device.
  4. On your Ledger, review the message carefully, then press both buttons to confirm.
  5. Copy the resulting signature hash from MetaMask.

Using Ledger with Electrum (Bitcoin)

  1. Open Electrum with your Ledger account loaded.
  2. Go to Tools → Sign/Verify Message.
  3. Paste the message from CoinJar into the Message field.
  4. Enter the Bitcoin address you're confirming into the Address field.
  5. Select Sign and confirm the action on your Ledger device.
  6. Copy the signature hash displayed in Electrum.

Trezor (with Trezor Suite)

  1. Open Trezor Suite and connect your device.
  2. Go to the account for the relevant cryptocurrency.
  3. From the account menu, select Sign & Verify.
  4. Choose Sign message.
  5. Paste the exact unique message from CoinJar and select Sign.
  6. Confirm the message on your Trezor device.
  7. Copy the signature hash displayed in Trezor Suite

Trust Wallet

Trust Wallet doesn't have a standalone "sign message" menu. Instead, you sign through a connected service using WalletConnect:

  1. Open the signing page you were directed to (for Ethereum, you can use Etherscan's Sign Message tool above) and choose WalletConnect.
  2. In Trust Wallet, go to Settings → WalletConnect and scan the QR code to connect.
  3. When the signing request appears in Trust Wallet, check that the message matches the one from CoinJar.
  4. Approve the request to sign.
  5. Copy the resulting signature hash from the signing page.

Other wallets

Most modern wallets support message signing, often labelled:

  • Sign message
  • Sign verification message
  • Sign & verify
  • Tools > Sign

If you can't find this feature, check your wallet provider's help documentation. If your wallet doesn't support message signing at all, return to CoinJar and use Satoshi Test or Manual Upload instead.

Step 3: Submit the signature to CoinJar

  1. Return to the Verify Wallet Ownership screen in CoinJar.
  2. Paste the signature hash into the Paste Signed Output field.
  3. Select Verify Wallet.

CoinJar will validate the signature instantly. If it's valid, your address is verified and you can begin transferring straight away.

If verification fails

Check the following:

  • You copied the full signature with no extra spaces or missing characters.
  • You signed the exact message CoinJar provided. No changes, including spaces or line breaks.
  • You signed with the same address you entered in CoinJar. Signing with a different address in the same wallet won't match.
  • Some hardware wallets show only a hash of the message on-screen during signing, this is normal and doesn't indicate a problem.

You may also change your wallet verification method by either choosing Satoshi Test or the Manual Upload method in the CoinJar app.

 


 



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