Blockstream App - Liquid

1. Introduction

1.1 Tutorial objective

• This tutorial explains how to use the Blockstream App mobile application to manage a Bitcoin Liquid wallet, i.e. transactions recorded directly on the Bitcoin "Liquid" side chain.
• It covers installation, initial configuration, creation of a software wallet, and operations for receiving and sending bitcoins on Liquid.
• Note: Other tutorials in the Appendices cover Onchain, Watch-Only and the desktop version.

1.2 Target audience

• Beginners: Users wishing to manage their bitcoins with an intuitive mobile application, integrating the Liquid network.
• Intermediate users: People seeking to understand onchain functionalities and privacy options such as Tor or SPV.

1.3 Introducing Liquid

• (1) Peg-in: Bitcoins (BTC) are locked onto the main Blockchain by the Liquid federation. In return, an equivalent amount of Liquid-Bitcoins (L-BTC), ensuring parity between the two chains, is issued on the Blockchain Liquid and sent to the user.
• (2) Independent transactions: Transactions can run simultaneously and independently on the main Blockchain (BTC) and Sidechain Liquid (L-BTC), depending on user requirements.
• (3) Peg-out: The user sends Liquid-Bitcoins (L-BTC) back to the Liquid federation. The federation then unlocks an equivalent amount of bitcoins (BTC) on the main Blockchain and transfers them to the user.

Why use Liquid?

• Speed: Transactions on Liquid are confirmed in around 1 minute, compared with 10 minutes or more for onchain transactions, thanks to blocks generated every minute by a federation of validators.
• Enhanced confidentiality: Liquid uses Confidential Transactions, which hides the amount and type of asset transferred, making transactions more private (although addresses remain visible).
• Low fees: Transactions on Liquid are generally less expensive, making them ideal for frequent transfers or small amounts.
• Multiple assets: In addition to L-BTCs, Liquid supports the issuance of other digital assets, such as stablecoins or tokens, for use in specific applications.
• Use cases: Liquid is particularly suitable for cross-platform exchanges, fast payments, or applications requiring smart contracts, while remaining linked to the security of Bitcoin.

1.4. Hot wallet reminder

• Hot Wallet, Software Wallet, Wallet mobile, software wallet: all names for an application installed on a smartphone, computer or any device connected to the Internet, enabling private keys from a Bitcoin wallet to be managed and secured.
• Unlike hardware wallets, also known as Cold wallets, which isolate keys offline, software wallets operate in a connected environment, making them more vulnerable to cyber-attacks.
• Recommended use:
  • Ideal for managing moderate amounts of bitcoin, especially for daily transactions.
  • Suitable for beginners or users with limited assets, for whom a Hardware Wallet may seem superfluous.
• Limitations: Less secure for storing large funds or long-term savings. In this case, choose a Hardware Wallet.

2. Introducing Blockstream App

• Blockstream App is a mobile (iOS, Android) and desktop application for managing Bitcoin wallets and assets on the Liquid network. Acquired by Blockstream in 2016, it was previously named Green Address and then Blockstream Green.
• Key features:
• Onchain transactions on Blockchain Bitcoin.
  • Transactions on the Liquid network (Sidechain for fast, confidential exchanges).
• Watch-only wallets for monitoring funds without access to keys.
  • Privacy options: connection via Tor, connection to a personal node via Electrum, or SPV verification to reduce dependency on third-party nodes.
  • Functions Replace-by-fee (RBF) to speed up unconfirmed transactions.
• Compatibility: Integrates hardware wallets such as Blockstream Jade.
• Interface: Intuitive for beginners, with advanced options for experts.
• Note: This guide focuses on onchain use. Other tutorials in the Appendices cover Onchain, Watch-Only and the desktop version.

3. Installing and configuring the Blockstream App

3.1. download

• For Android:
  • Download Blockstream App from the Google Play Store.
  • Alternative: Install via the APK file available on Blockstream's official GitHub.
• For iOS:
  • Download Blockstream App from the App Store.
• Note: Be sure to download from official sources to avoid fraudulent applications.

3.2. initial configuration

• Home screen: When first opened, the application displays a screen without a configured wallet. Created or imported wallets will appear here later.

• Customize settings: Click on "Application settings", adjust the options below, click on "Save", restart the application and create your wallet.

3.2.1. Enhanced privacy (Android only)

• Function: Disables screenshots, hides application previews in the task manager, and locks access when the phone is locked.
• Why?: Protects your data against unauthorized physical access or screen-capturing malware.

3.2.2. Connection via Tor

• Function: Route network traffic via Tor, an anonymous network that encrypts your connections.
• Why?: Hide your IP address and protect your privacy, ideal if you don't trust your network (public Wi-Fi, for example).
• Disadvantage: May slow down the application due to encryption.
• Recommendation: Activate Tor if confidentiality is a priority, but test connection speed.

3.2.3. Connecting to a personal node

• Function: Connects the application to your own complete Bitcoin node via a Electrum server.
• Why?: Provides total control over Blockchain data, eliminating dependency on Blockstream servers.
• Prerequisite: A configured Bitcoin node.
• Recommendation: Advanced users who want maximum sovereignty.

3.2.4. SPV verification

• Function: Uses Simplified Payment Verification (SPV) to directly verify certain Blockchain data without downloading the entire chain.
• Why?: Reduces dependency on Blockstream's default node, while remaining lightweight for mobile devices.
• Disadvantage: Less secure than a full node, as it relies on third-party nodes for some information.
• Recommendation: Activate SPV if you can't use a personal node, but prefer a full node for optimum security.

4. Creating a Bitcoin onchain wallet

4.1. Start creation

• Caution: Set up your wallet in a private environment, without cameras or observers.
• From the home screen, click on "Get Started" :

• If you want to manage a Cold Wallet (offline wallet): click on "Connect Jade " to use the Hardware Wallet Blockstream Jade or other compatible Cold wallets.

• The next screen appears:

• (1) "Setup Mobile Wallet" : Create a new hot wallet (Hot Wallet).
• (2) "Restore from Backup ": Import an existing wallet using a mnemonic phrase (12 or 24 words). Warning: Do not import the phrase from a Cold Wallet, as it will be exposed on a connected device, invalidating its security.
• (3) "Watch-Only ": Import an existing read-only wallet, to view the balance (e.g. of your Cold Wallet) without exposing the mnemonic phrase. See the "Watch Only" tutorial in the appendix.

4.2. Save seed phrase

• On the Wallet home screen, click on the "Security" tab, then on the "Back Up" prompt or the "Recovery Phrase" menu:

• Write down your recovery phrase with the utmost care. Write it down on paper or metal and keep it in a safe place (safe, offline location). This phrase is your only means of accessing your bitcoins in the event of loss of your device or deletion of the application.
• It's also important to note that anyone with this phrase can steal all your bitcoins. Never store it digitally:
• No screenshot
• No cloud, email or messaging backups
• No copy/paste (risk of saving to clipboard)

Back up your mnemonic phraseDiscover best practices for safeguarding your Bitcoin wallet

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4.3. Check seed sentence

• On the Wallet home screen, click on the "Settings" tab, then on "Wallet Details", and copy the zPub (extended public key:

• Delete the application, then restore the wallet via "Restore from Backup " by entering the mnemonic phrase, and check that the zpub is unchanged. If yes, then your backup is correct, and you can send funds to the Wallet.
• To learn more about how to perform a recovery test, here is a dedicated tutorial :

Recovery TestHow to test your backups to ensure you don't lose your bitcoins?

4.4. Securing access to the application

• From the Wallet home screen, go to "Security " then click on "PIN "
• Enter and confirm a random 6-digit PIN code.

5. Using the Liquid wallet

5.1. Receive "L-BTC" bitcoins

• From the wallet home screen, click on '"Transact" then "Receive ".

• By default, the application displays a blank receipt address, onchain (SegWit v0 format, starting with bc1q...). Click on "Bitcoin" to select Liquid Bitcoin :

• Options:
• (1) Click on the arrows to select another new address linked to this seed sentence.
  • (2) You can also choose an address from among those already used/displayed, by clicking on the three dots at top right and then on "List of Addresses"
  • (3) To request a specific amount, click on the three dots at top right, select "Request amount", and enter the desired amount. The QR will be updated, and the address will be replaced by a Bitcoin payment URI.

• Share the address/URI by clicking on "Share", copying the text or scanning the QR code.
• Verification: Check the address shared with the recipient as far as possible to avoid errors or attacks (e.g. malware modifying the clipboard).

5.2. send bitcoins

• From the wallet home screen, click on "Transact" then "Send " :

• Enter details:
  • (1) Enter the address of the recipient by sticking it on or scanning a QR code.
  • (2) Check the assets and the account from which the funds are being sent.
  • (3) Indicate the amount to be sent. You can choose the unit: L-BTC, L-satoshis, USD, ...

• Check:
  • Check the address, amount and charges on the summary screen.
  • An address error can result in irreversible loss of funds. Beware of malware that modifies the clipboard.

• Confirmation: Slide the "Send" button to sign and distribute the transaction.
• Follow-up: In the Wallet "Transact" tab, the transaction appears as "Unconfirmed", then "Confirmed", then "Completed":

• The time between 2 blocks is 1 minute on Liquid, so the transaction is quickly confirmed and completed.

Appendices

A1. Other Blockstream App tutorials

Blockstream App - OnchainSet up Blockstream App on mobile and manage onchain transactions

Blockstream App - Watch-OnlyHow do I configure a Watch-only wallet on Blockstream App?

Blockstream App - DesktopHow to use your Hardware Wallet with Blockstream App on a computer?

A2. Best practices

• Secure your recovery phrase:
• Tutorial: Saving your mnemonic phrase

Back up your mnemonic phraseDiscover best practices for safeguarding your Bitcoin wallet

Bitcoin Wallet Architecture

Intermediate

4.7(92)

Dive into the cryptographic principles that power Bitcoin wallets.

4.7(92)

ProfessorLoïc Morel

Duration10 hours

See the course

Bitcoin Wallet Architecture

Dive into the cryptographic principles that power Bitcoin wallets.

Loïc Morel

Intermediate

10 hours

4.7(92)

• Use secure authentication:
• Activate a strong PIN or biometric authentication (fingerprint or facial recognition) to protect access to the application.
• Never share your PIN or biometric data.
• Protect your privacy:
• Generate a new address for each onchain reception or Liquid to limit tracing on the Blockchain.
• Activate the "Enhanced Privacy", "Tor" and "SPV" functions.
• For maximum confidentiality, connect your Wallet to your own Bitcoin node via an Electrum server instead of using the public node
• Choose the network best suited to your needs:
• Onchain: Preferred for long-term custody or large-value transactions (fees negligible in relation to amount).
• Liquid: Use for fast, low-cost transfers with enhanced confidentiality.
• Lightning: Choose instant, low-cost transfers for small amounts.
• Always check shipping addresses:
• Before sending funds, check the address carefully. Funds sent to the wrong address are lost forever. Use copy/paste or QR code scanning, never copy/modify an address by hand.
• Optimize costs:
• For onchain transactions, choose appropriate fees (slow, medium, fast) according to urgency and network congestion.
• Use Liquid, or Lightning for small amounts.
• Keep the application up to date

A3. Additional resources

• Official links:
• Official website
• Support for the mobile application: documentation and chat
• GitHub
• Block Explorers:
• on chain : Mempool.space
• Liquid : Blockstream Info
• Lightning: 1ML (Lightning Network)
• Learning and tutorials: Plan ₿ Academy
• Securing your recovery phrase

Back up your mnemonic phraseDiscover best practices for safeguarding your Bitcoin wallet

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Duration10 hours

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