Blockstream AMP Case Studies

Case Study 1: Bermudian Stimulus Token Pilot

The Problem

The Bermudian government wants to provide financial stimulus to those citizens affected by COVID-19 and ensure that citizens spend that stimulus within the local economy. However, traditional solutions had severe drawbacks.

  • The physical distribution of debit cards is slow and expensive.

  • Stimulus funds cannot be targeted toward local businesses to benefit the local economy with direct payments or debit cards.

The Solution

Using Blockstream AMP, Stablehouse worked with the Bermudian government to develop a testing program to demonstrate the feasibility of a digital token-based stimulus program.

Testers downloaded Blockstream Green to their smartphone and registered a wallet with Stablehouse. Stablehouse enabled a digital test token that was distributed to the testers. The token was only transferable to a limited amount of other testers, ensuring that the stimulus remained within the local economy and a whitelisted group of users.

Stablehouse worked with a test group of merchants to provide a point-of-sale solution to accept payment of these tokens. Stablehouse provided each merchant with an inexpensive device capable of generating an invoice for their customer for each transaction. Customers used their smartphones to scan the QR code and complete their payment with the token. The system could be designed so that the government could reimburse each merchant for the tokens received.


  • Accessible to anyone with an Android or iOS device.

  • Easy setup for merchants.

  • Recurring payments can be made at a low cost.

  • Ability to ensure benefits remain within the local economy.

How it Works

Selecting an Asset Type

Two types of assets can be issued in Blockstream AMP: transfer-restricted assets and issuer-tracked assets. Stablehouse—as the pilot issuer in this case—used transfer-restricted assets to ensure that citizens could only spend the stimulus tokens at approved merchants.

Issuing the Asset

Using Blockstream AMP, Stablehouse first created and registered the tokens using Blockstream AMP. The tokens were then sent to Stablehouse’s treasury wallet. The treasury wallet can issue more of the token (“reissuance”) when required.

At issuance, Stablehouse chose a ticker, name, icon, and associated domain. Stimulus recipients can use this data to verify that the tokens they receive are genuine.

Configuring the Transfer Rules

Out of the box, Blockstream AMP supports restrictions based on categories (each user can be assigned one or more categories when they register their account). However, in this instance, a more sophisticated scheme was required to ensure transactions could only occur in one direction—from testers to merchants.

To accomplish this, Stablehouse used the authorization override feature of Blockstream AMP to approve or deny transfers based on their own system’s logic. If the intended recipient of the transfer was one of the approved merchants, it was allowed; otherwise, it was denied.

Transfer-restricted asset approval process (category-based)

Transfer-restricted asset approval process (using issuer API override)

Building the Point-of-Sale

The technology provider built the point-of-sale (POS) on the low-cost, open-source M5 stack device. Each merchant’s POS connects to a remote server that generates the invoice and notifies the device when a transaction is complete.

The technology provider implemented the server using BTCPay Server, which supports Liquid assets. Whenever BTCPay Server generates an invoice, the merchant requesting the invoice is tagged on the transaction so that reconciliation can occur.

Each address that is generated by the BTCPay Server invoice is automatically whitelisted and used to approve transactions through the Blockstream AMP callback function. Blockstream AMP uses this whitelist to approve transactions through the callback function.

Distributing the Stimulus Token

Stablehouse distributed the stimulus token to each of the registered users in the system. A small amount of L-BTC was also sent to each user to ensure they can cover network fees (currently 0.1 sats / vbyte). Future versions of the program could include customized wallets built on top of the Green Development Kit (GDK) that allow for a completely customized experience.

Case Study 2: Exordium Security Token

The Problem

Exordium, the publisher of massively-multiplayer space strategy game Infinite Fleet (developed by Pixelmatic), is issuing a digital equity token. However, popular token issuance solutions posed several challenges:

  • Issuers must implement the transfer restrictions required by security tokens at the smart-contract level, making it very difficult to adapt to fast-moving regulations worldwide.

  • Platforms such as Ethereum are showing the strain of adoption, with unreliable transaction times and excessive transaction fees.

  • A lack of on-chain privacy leads to investors revealing sensitive information about their financial activities.

The Solution

Exordium is working with technology and compliance provider STOKR to issue a digital equity or security token known as EXO on the Liquid Network, using Blockstream AMP (subject to regulatory approval). The token will provide a profit share to investors from the game’s profits. The EXO token is also compatible to receive an ISIN code. ISIN codes are beneficial for institutional investors to track investment holdings consistently across markets worldwide.

Using Blockstream Green, each investor can register their Managed Asset Account with STOKR or other issuance partners. By registering, an investor is added to a list of approved investors, enabling them to receive and send the EXO token.

Blockstream AMP implements transfer restrictions through a simple multisig authorizer setup, providing Exordium with flexibility to adapt to shifting regulations. Liquid’s cutting-edge privacy technology, Confidential Transactions, secures users’ sensitive financial data. The Liquid Network also currently offers much lower transaction fees than other issuance platforms and supports the Lightning Network for further scale if needed.


  • Transfer restrictions implemented at the protocol level using multisig.

  • Adaptable to shifting regulations through Blockstream AMP’s authorizer API.

  • Secures the financial privacy of investors.

  • Immediate wallet support with Blockstream Green.

How it Works

Selecting an Asset Type

Two types of assets can be created in Blockstream AMP: transfer-restricted assets and issuer-tracked assets. Exordium used transfer-restricted assets to ensure that only approved investors could send and receive the EXO token.

Issuing the Asset

Exordium, together with STOKR, will issue the EXO token using Blockstream AMP. The newly-issued EXO token will then be sent to Exordium’s treasury wallet in preparation for distribution to registered investors.

Exordium will hold reissuance keys so that they can authorize additional tokens according to their allocations (e.g., future equity sale). The issuance will not be confidential, which means that anyone can verify the total supply at any time.

At issuance, Exordium will choose a ticker, name, icon, and associated domain. Investors can use this data to verify that Exordium genuinely issued the asset they receive.

Configuring the Transfer Rules

Exordium will implement EXO transfer restrictions using Blockstream AMP’s in-built category-based controls. STOKR will assign each registered investor to a unique category: approved KYC/AML status.

Only investors that satisfy this category can receive or send the EXO token. The multisig authorizer will deny any transactions sent to users that do not satisfy the correct category requirements by refusing to sign the second multisig key.

The authorizer is implemented through Blockstream Green.

Transfer-restricted asset approval process (category-based)

Transfer-restricted asset approval process (using categories)

Distributing the Security Token

STOKR will calculate the relevant token amount to be received by each investor that has purchased simple agreements or future tokens (SAFTs), then supply this data to Exordium. Exordium will then distribute the EXO token to the investors from their treasury wallet. A small amount of L-BTC will also be sent to each investor to ensure they can cover Liquid Network transaction fees.

Distributing Profit Shares

On the date and time that the profit shares are due, STOKR will temporarily freeze all EXO transfers using the Blockstream AMP API. STOKR will then use Blockstream AMP API to get a full ownership report, calculate the required profit share payments, and retrieve a new receive address for each investor.

Exordium will then make the payments to the investors according to this information. After completing the profit share payments outside of Blockstream AMP, Exordium uploads records of the payments to Blockstream AMP via the API, ensuring that all relevant data on investor activity is stored in one central location.