top of page

Crypto Asset Custody

• Security

Our patented key management systems along with Hierarchical Threshold Signature Scheme (HTSS) technology ensures that your private keys are neither exposed in transit nor being reconstructed in the full form.

• API/Webhooks

Understanding the pain points of developing blockchain applications, we design the easy to integrate, yet secure blockchain API. In addition, we provide plenty of webhooks so that you can get notified whenever there is any update on your interested addresses or transactions.

• Reliability

All our services are running in the highly available and disaster recoverable Kubernetes clusters by our dedicated reliability team. All the secret shares are also securely backed up in a multi-cloud infrastructure to ensure both the service and asset availability.

Blockchain Service

• Explorer API

Develop blockchain applications with our robust explorer API. Under the hood, all our services are running in the highly available and disaster recoverable Kubernetes clusters by our dedicated reliability team. 

• Node hosting and management

With our smart node management technology, we are able to run a cluster of blockchain nodes to ensure the accessibility, data consistency, and in time transaction broadcasting.

• Private/Consortium chain construction

Case study: Fubon Bank and Taishin Bank instant blockchain settlement regulatory sandbox experiment.

In this experiment we built a consortium chain for Fubon Bank and Taishin Bank in the domestic fund transfer and payment service. With the explorer API, smart node management mentioned above, and asset custody service, Fubon and Taishin are able to integrate the consortium chain mechanisms into their banking systems.

• Consensus

AMIS team has being an active contributor to Ethereum community on Casper, Plasma, and sharding development. AMIS has also contributed the Istanbul Byzantine Fault Tolerance (IBFT) consensus to public Ethereum as well as J.P. Morgan Quorum ( Currently, it is one of the default consensus algorithms supported in Quorum.

Blockchain Service

Hierarchical Threshold Signature

Comparing to Threshold Signature Scheme (TSS), shares in this scheme are allowed to have different ranks.

The main merit of HTSS is vertical access control such that it has "partial accountability”. Although TSS achieves joint control to disperse risk among the participants, the level of all shares are equal. It is impossible to distinguish which share getting involved in an unexpected signature. TSS is not like the multi-signature scheme as the signature is signed by distinct private keys in multi-signature scheme. It is because Shamir’s secret sharing only supports horizontal access control.


For example, an important contract not only requires enough signatures, but also needs to be signed by a manager. Despite the fact that vertical access control can be realized on the application layer and tracked by an audit log. Once a hack happens, we will have no idea about who to blame for. However, in HTSS framework, through assigning different ranks of each share induces that any valid signature generated includes the share of the manager.


HTSS has been developed by Tassa and other researchers many years ago. In our implementation, we setup up this theory on TSS(i.e. just replace Lagrange Interpolation to Birkhoff Interpolation). Meanwhile, our protocol of sign (i.e. GG18 and CCLST20 ) can support two homomorphic encryptions which are Paillier and CL scheme.

• Introduction Article: Introduction to Hierarchical Threshold Signature 

• Example: Hierarchical Threshold Signature demonstration

• Source: Alice - Hierarchical Threshold Signature Scheme



• Asset Custody Wallet Service

AMIS Wallet Service is a total solution for asset custody in various industrial use cases, ranging from hot, warm, to cold storages. Our proprietary hierarchical threshold signature (HTSS) technology, a derivation of threshold signature (TSS), enables the accountability capability on top threshold signature wallets. In a nutshell, private keys in AMIS wallet server would never exist anywhere, which also means it is never in transit, nor at rest.

• DeFi Multisig Wallet

Seeing the lack of secure DeFi Multisig Wallet, we extended Gnosis Safe ( to support DeFi functions. Now all your DeFi operations can take advantage of Gnosis Safe’s multisig approval processes.

• Cold Storage

AMIS cold storage is a combination of software, hardware, and process. Every element inside is designed from proven standard with minimal external dependencies. Customers would have 100% control over their own assets.

bottom of page