An Iroha entity that is able to perform specified set of actions. Each account belongs to one of existing domains.
Any countable commodity or value. Each asset is related to one of existing domains. For example, an asset can represent any kind of such units - currency unit, a bar of gold, real estate unit, etc.
Transaction data is permanently recorded in files called blocks. Blocks are organized into a linear sequence over time (also known as the block chain) .
- hash — SHA3-512 hash of block protobuf payload
- signatures — signatures of peers, which voted for the block during consensus round
- height — a number of blocks in the chain up to the block
- timestamp — Unix time (in milliseconds) of block forming by a peer
- body — transactions, which successfully passed validation and consensus step
- transactions quantity
- previous hash of a block
4.1.5. Block Creator¶
Any application that uses Iroha is treated as a client.
A distinctive feature of Iroha is that all clients are using simple client-server abstractions when they interact with a peer network: they don’t use any abstractions which are specific for blockchain-related systems. For example, in Bitcoin clients have to validate blocks, or in Fabric they need to poll several peers to make sure that a transaction was written in a block, whereas in Iroha a client interacts with any peer similarly to a single server.
A consensus algorithm is a process in computer science used to achieve agreement on a single data value among distributed processes or systems. Consensus algorithms are designed to achieve reliability in a network involving multiple unreliable nodes. Solving that issue – known as the consensus problem – is important in distributed computing and multi-agent systems.
Consensus, as an algorithm
An algorithm to achieve agreement on a block among peers in the network. By having it in the system, reliability is increased.
Consensus, as a component
Preserves consistent state among the peers within a peer network. Iroha uses own consensus algorithm called Yet Another Consensus (aka YAC). Distinctive features of this algorithm are its scalability, performance, and Byzantine fault tolerance. If there are missing blocks, they will be downloaded from another peer via Synchronizer. Committed blocks are stored in Ametsuchi block storage.
4.1.10. Ordering Gate¶
Internal Iroha component that passes transactions from Peer Communication Service to Ordering Service. Ordering Gate eventually recieves proposals from Ordering Service and sends them to Simulator for stateful validation.
4.1.11. Ordering Service¶
- Time limit dedicated to transactions collection has expired.
- Ordering service has received the maximum amount of transactions allowed for a single proposal.
Both parameters (timeout and maximum size of proposal) are configurable (check environment-specific parameters page).
A common precondition for both triggers is that at least one transaction should reach ordering service. Otherwise, no proposal will be formed.
4.1.13. Peer Communication Service¶
A named rule that gives the privilege to perform a command. Permission cannot be granted to an account directly, instead, an account has roles, which are the collection of permissions.
22.214.171.124. Grantable Permission¶
Only grantable permission is given to an account directly. An account that holds grantable permission is allowed to perform some particular action on behalf of another account. For example, if the account a@domain1 gives the account b@domain2 a permission that it can transfer assets — then b@domain2 can transfer assets of a@domain1 to anyone.
A request to Iroha that does not change the state. By performing a query, a client can get request data from the state, for example a balance of his account, a history of transactions, etc.
An ordered set of commands, which is applied to the ledger atomically. Any nonvalid command within a transaction leads to rejection of the whole transaction during the validation process.
There are two kinds of validation - stateless and stateful.
126.96.36.199. Stateless Validation¶
Performed in Torii. Checks if an object is well-formed, including the signatures.
4.1.23. Verified Proposal Creator¶
Internal Iroha component that performs stateful validation of transactions contained in received proposal. On the basis of transactions that have been passed stateful validation verified proposal will be created and passed to Block Creator. All the transactions that have not passed stateful validation will be dropped and not included in a verified proposal.