The Bubble SDK contains javascript libraries for developers building with Bubble Protocol on EVM-based blockchains.
- Core - core classes, types, constants and utilities.
- Client - client libraries for application developers.
- Server - server-side libraries for developers of off-chain storage services.
- Crypto - cryptographic functions and classes for different blockchains.
- Contracts - the smart contract required interface and example contracts.
- Developers of decentralised applications.
- Developers of bubble-compatible off-chain storage services.
- Companies looking to move into Web3.
Bubble Protocol provides access-controlled off-chain storage for Web3 applications and allows blockchains to govern private data. It adds Web3 capabilities to any storage system, whether a cloud relay server, decentralized storage network, home server, or private company infrastructure. One such server is the Bubble Private Cloud, a cloud server that can be used to build and experiment with Bubble Protocol.
Bubble Protocol is blockchain agnostic and is designed to be highly adaptable, providing Web3 developers with an easy to use general purpose global data layer for data tokenisation, cross-device DApp storage, decentralised identity solutions, web3 privacy compliance solutions, paywalled content, NFT content, and much more.
Bubble Protocol adds on-chain access control to any off-chain storage system. By integrating our Guardian software, any storage system can become a host for web3 applications. DApp developers can custom design smart contracts to govern access to content for specific users, specifying fine-grained permissions akin to POSIX-style permission bits. Identification of users is via their public key and enforcement of the permissions is carried out by the off-chain storage service, which is chosen by the user or developer.
Custom smart contracts are simple to develop and need only implement a single method. Once a contract is deployed, the off-chain content can be saved on any bubble-compatible storage system that supports the user's preferred blockchain. See Access Control Contracts in the Client Library for more information.
Each piece of off-chain content is uniquely identified globally by a Content ID. See Content IDs in the Client Library for more information.
The set of off-chain content controlled by a smart contract, combined with the on-chain logic of the contract itself, is known as a bubble, and is where Bubble Protocol gets it's name. For more details, see Bubbles below.
See the whitepaper for more details.
Off-chain storage services can be public or private, centralised or decentralised.
The protocol allows each storage service to essentially function as a generic host for any bubble, allowing a single service to provide off-chain storage for any type of Web3 application. Service providers can choose whether to provide an open, public service - like the Bubble Private Cloud - or a private service restricted to specific users, like customers or employees of a company.
Off-chain storage services can be implemented easily using the Server Library.
With all application logic on-chain, public off-chain storage services have few requirements beyond the quality of storage service they provide. This partitioning, alongside cross-chain functionality and the ability of users to choose which service they trust for each application they use, cultivates a separation of concerns that helps to drive decentralisation.
A bubble is the name given to a set of content controlled and protected by a smart contract implementing the AccessControlledStorage interface.
A bubble is an off-chain container holding files and directories with access control handled by it's on-chain smart contract. Any smart contract can act as the controller for a bubble, it just needs to implement the interface's single getAccessPermissions method.
Each Bubble has a globally unique ID derived from the smart contract (it's address and chain ID) and the storage location of the bubble (normally the URL of the storage system's API). The bubble ID forms part of the content id of each file the bubble holds.
A bubble has a life cycle that follows it's smart contract, allowing it to be created, transitioned and terminated.
Using Bubble Protocol, a smart contract's innate state and transaction capabilities can be harnessed to transition access to specific bubble content as the life cycle progresses. In essence, the data life cycle is encoded in the smart contract. For data protection use cases this means the smart contract can act as a service-level agreement, one that is public, immutable and irrefutable.
When a bubble's smart contract indicates it has been terminated (by returning the Bubble Terminated bit in the getAccessPermissions method), the storage system is required to pop the bubble, deleting all bubble content.
Files within a directory inherit their access permissions from their parent directory. Directories and files in a bubble can be listed (if the user has read permissions) to obtain such properties as length and modify time. These features can be useful to decentralised applications, enabling such features as device synchronisation and data backup.
Where supported by the storage system, clients can subscribe to files and directories to receive near real-time notifications when they are updated. This allows bubbles to be used as basic back-end servers for certain types of decentralised applications, such as messaging dapps and social media dapps.
The client library provides a Bubble class that encapsulates a bubble hosted on a remote storage system. In addition to providing methods to read, write, append and delete content, it allows directories to be listed and the bubble to be managed.
Bubbles can be managed and content can be accessed easily using the ContentManager and Bubble classes in the Client Library.