blob

README

x/blob

Abstract

The x/blob module enables users to pay for arbitrary data to be published to the Celestia blockchain. Users create a single BlobTx that is composed of:

1. Multiple Blobs (Binary Large OBjects): the data they wish to publish. A single Blob is composed of:
   1. NamespaceId []byte: the namespace this blob should be published to.
   2. Data []byte: the data to be published.
   3. ShareVersion uint32: the version of the share format used to encode this blob into a share.
2. A single sdk.Tx which is composed of:
   1. Signer string: the transaction signer
   2. NamespaceIds []byte: the namespaces they wish to publish each blob to. The namespaces here must match the namespaces in the Blobs.
   3. ShareCommitment []byte: a share commitment that is the root of a Merkle tree where the leaves are share commitments to each blob associated with this BlobTx.

After the BlobTx is submitted to the network, a block producer separates the transaction from the blob. Both components get included in the data square in different namespaces: the BlobTx gets included in the PayForBlobNamespace and the associated blob gets included in the namespace the user specified in the original BlobTx. Further reading: Message Block Layout

After a block has been created, the user can verify that their data was included in a block via a blob inclusion proof. A blob inclusion proof uses the ShareCommitment in the original transaction and subtree roots of the block's data square to prove to the user that the shares that compose their original data do in fact exist in a particular block.

State

The blob module doesn't maintain it's own state.

When a MsgPayForBlob is processed, it consumes gas based on the blob size.

Messages

• MsgPayForBlob pays for the blob to be included in the block.

PrepareProposal

When a block producer is preparing a block, they must perform an extra step for BlobTxs so that end-users can find the blob shares relevant to their submitted BlobTx. In particular, block proposers wrap the BlobTx in the PayForBlob namespace with the index of the first share of the blob in the data square. See Non-interactive Default Rules for more details.

Since BlobTxs can contain multiple blobs, the BlobTx is wrapped with one share index per blob in the transaction. The index wrapped transaction is called an IndexWrapper and this is the type that gets marshalled and written to the PayForBlobNamespace.

Events

The blob module emits the following events:

Blob Events

EventPayForBlob

Attribute Key	Attribute Value
signer	{bech32 encoded signer address}
blob_size	{size in bytes}
namespace_ids	{namespaces the blobs should be published to}

Parameters

Key	Type	Example
MinSquareSize	uint32	1
MaxSquareSize	uint32	128

Usage

celestia-app tx blob payForBlob <hex encoded namespace> <hex encoded data> [flags]

For submitting PFB transaction via a light client's rpc, see celestia-node's documention.

While not directly supported, the steps in the SubmitPayForBlob function can be reverse engineered to submit blobs programmatically.

How is the ShareCommitment generated?

1. For each blob in the BlobTx:
   1. Split the blob into shares of size appconsts.ShareSize
   2. Determine the BlobMinSquareSize (the minimum square size the blob can fit into). This is done by taking the number of shares from the previous step and rounding up to the next perfect square that is a power of two.
   3. Arrange the shares into a Merkle mountain range where each tree in the mountain range has a maximum size of the BlobMinSquareSize.
   4. Take the roots of the trees in the Merkle mountain range and create a new Merkle tree.
   5. The share commitment of this blob is the Merkle root of the Merkle tree from the previous step.
2. Compose a Merkle tree where the leaves are all the share commitments from the previous step. The share commitment of the BlobTx is the Merkle root of this tree.

Documentation

Overview

blob is a Cosmos SDK module that enables users to pay for data to be published to the Celestia blockchain. Please see ./README.md for the full specification of this module.

Index

• func ExportGenesis(ctx sdk.Context, k keeper.Keeper) *types.GenesisState
• func InitGenesis(ctx sdk.Context, k keeper.Keeper, genState types.GenesisState)
• func NewHandler(k keeper.Keeper) sdk.Handler
• func SubmitPayForBlob(ctx context.Context, signer *types.KeyringSigner, conn *grpc.ClientConn, ...) (*sdk.TxResponse, error)
• type AppModule
  • func NewAppModule(cdc codec.Codec, keeper keeper.Keeper) AppModule
  • func (am AppModule) BeginBlock(_ sdk.Context, _ abci.RequestBeginBlock)
  • func (AppModule) ConsensusVersion() uint64
  • func (am AppModule) EndBlock(_ sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate
  • func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.RawMessage
  • func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, gs json.RawMessage) []abci.ValidatorUpdate
  • func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sdk.Querier
  • func (am AppModule) Name() string
  • func (AppModule) QuerierRoute() string
  • func (am AppModule) RegisterInvariants(_ sdk.InvariantRegistry)
  • func (am AppModule) RegisterServices(cfg module.Configurator)
  • func (am AppModule) Route() sdk.Route
• type AppModuleBasic
  • func NewAppModuleBasic(cdc codec.BinaryCodec) AppModuleBasic
  • func (AppModuleBasic) DefaultGenesis(cdc codec.JSONCodec) json.RawMessage
  • func (AppModuleBasic) GetQueryCmd() *cobra.Command
  • func (a AppModuleBasic) GetTxCmd() *cobra.Command
  • func (AppModuleBasic) Name() string
  • func (AppModuleBasic) RegisterCodec(cdc *codec.LegacyAmino)
  • func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux)
  • func (a AppModuleBasic) RegisterInterfaces(reg cdctypes.InterfaceRegistry)
  • func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino)
  • func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router)
  • func (AppModuleBasic) ValidateGenesis(cdc codec.JSONCodec, config client.TxEncodingConfig, bz json.RawMessage) error

Functions

func ExportGenesis

func ExportGenesis(ctx sdk.Context, k keeper.Keeper) *types.GenesisState

ExportGenesis returns the capability module's exported genesis.

func InitGenesis

func InitGenesis(ctx sdk.Context, k keeper.Keeper, genState types.GenesisState)

InitGenesis initializes the capability module's state from a provided genesis state.

func NewHandler

func NewHandler(k keeper.Keeper) sdk.Handler

NewHandler uses the provided blob keeper to create an sdk.Handler

func SubmitPayForBlob

func SubmitPayForBlob(
	ctx context.Context,
	signer *types.KeyringSigner,
	conn *grpc.ClientConn,
	blobs []*types.Blob,
	opts ...types.TxBuilderOption,
) (*sdk.TxResponse, error)

SubmitPayForBlob builds, signs, and synchronously submits a PayForBlob transaction. It returns a sdk.TxResponse after submission.

Types

type AppModule

type AppModule struct {
	AppModuleBasic
	// contains filtered or unexported fields
}

AppModule implements the AppModule interface for the capability module.

func NewAppModule

func NewAppModule(cdc codec.Codec, keeper keeper.Keeper) AppModule

func (AppModule) BeginBlock

func (am AppModule) BeginBlock(_ sdk.Context, _ abci.RequestBeginBlock)

BeginBlock executes all ABCI BeginBlock logic respective to the capability module.

func (AppModule) ConsensusVersion

func (AppModule) ConsensusVersion() uint64

ConsensusVersion implements ConsensusVersion.

func (AppModule) EndBlock

func (am AppModule) EndBlock(_ sdk.Context, _ abci.RequestEndBlock) []abci.ValidatorUpdate

EndBlock executes all ABCI EndBlock logic respective to the capability module. It returns an empty list of validator updates.

func (AppModule) ExportGenesis

func (am AppModule) ExportGenesis(ctx sdk.Context, cdc codec.JSONCodec) json.RawMessage

ExportGenesis returns the capability module's exported genesis state as raw JSON bytes.

func (AppModule) InitGenesis

func (am AppModule) InitGenesis(ctx sdk.Context, cdc codec.JSONCodec, gs json.RawMessage) []abci.ValidatorUpdate

InitGenesis performs the capability module's genesis initialization. It returns an empty list of validator updates.

func (AppModule) LegacyQuerierHandler

func (am AppModule) LegacyQuerierHandler(legacyQuerierCdc *codec.LegacyAmino) sdk.Querier

LegacyQuerierHandler returns the capability module's Querier.

func (AppModule) Name

func (am AppModule) Name() string

Name returns the capability module's name.

func (AppModule) QuerierRoute

func (AppModule) QuerierRoute() string

QuerierRoute returns the capability module's query routing key.

func (AppModule) RegisterInvariants

func (am AppModule) RegisterInvariants(_ sdk.InvariantRegistry)

RegisterInvariants registers the capability module's invariants.

func (AppModule) RegisterServices

func (am AppModule) RegisterServices(cfg module.Configurator)

RegisterServices registers a GRPC query service to respond to the module-specific GRPC queries.

func (AppModule) Route

func (am AppModule) Route() sdk.Route

Route returns the capability module's message routing key.

type AppModuleBasic

type AppModuleBasic struct {
	// contains filtered or unexported fields
}

AppModuleBasic implements the AppModuleBasic interface for the capability module.

func NewAppModuleBasic

func NewAppModuleBasic(cdc codec.BinaryCodec) AppModuleBasic

func (AppModuleBasic) DefaultGenesis

func (AppModuleBasic) DefaultGenesis(cdc codec.JSONCodec) json.RawMessage

DefaultGenesis returns the capability module's default genesis state.

func (AppModuleBasic) GetQueryCmd

func (AppModuleBasic) GetQueryCmd() *cobra.Command

GetQueryCmd returns the capability module's root query command.

func (AppModuleBasic) GetTxCmd

func (a AppModuleBasic) GetTxCmd() *cobra.Command

GetTxCmd returns the capability module's root tx command.

func (AppModuleBasic) Name

func (AppModuleBasic) Name() string

Name returns the capability module's name.

func (AppModuleBasic) RegisterCodec

func (AppModuleBasic) RegisterCodec(cdc *codec.LegacyAmino)

func (AppModuleBasic) RegisterGRPCGatewayRoutes

func (AppModuleBasic) RegisterGRPCGatewayRoutes(clientCtx client.Context, mux *runtime.ServeMux)

RegisterGRPCGatewayRoutes registers the gRPC Gateway routes for the module.

func (AppModuleBasic) RegisterInterfaces

func (a AppModuleBasic) RegisterInterfaces(reg cdctypes.InterfaceRegistry)

RegisterInterfaces registers the module's interface types

func (AppModuleBasic) RegisterLegacyAminoCodec

func (AppModuleBasic) RegisterLegacyAminoCodec(cdc *codec.LegacyAmino)

func (AppModuleBasic) RegisterRESTRoutes

func (AppModuleBasic) RegisterRESTRoutes(clientCtx client.Context, rtr *mux.Router)

RegisterRESTRoutes registers the capability module's REST service handlers.

func (AppModuleBasic) ValidateGenesis

func (AppModuleBasic) ValidateGenesis(cdc codec.JSONCodec, config client.TxEncodingConfig, bz json.RawMessage) error

ValidateGenesis performs genesis state validation for the capability module.