• List of preconditions which must be satisfied before the use case can be applied
• Each precondition should be defined as the point in the list

Use case flow

1. The enumerated list of actions, which describes the interaction between actors step by step
2. Each step should involve a single actor as an object of the action
3. Each step can involve one or more actors as a subject of the action
4. Each use case can involve other use cases as dependencies by include or extend relationships

• One or more results of successfully finished use case

• List of alternative flows that can happen with the use case.
• Each entry should have the link to the step of the main use case flow when the alternative can occur
  • If needed, each entry can contain sub-entries
• Each entry should describe the consequences of the alternative flow

• List of exceptions that can happen during the use case flow, which can prevent it to be successfully finished
• Each entry should have the link to the step of the main use case flow when the exception can occur
  • If needed, each entry can contain sub-entries
• Each entry should describe the consequences of the exception

• The administrator has configured environment for running Iroha executables
• The administrator has prepared the genesis block

Use case flow

1. The administrator launches the command to run Iroha peer and providing the path to the genesis block description
2. The Iroha peer read and validates the genesis block configuration
3. The Iroha peer starts the Iroha network according to the configuration in the genesis block
4. The Iroha peer provides "successfully started" report to the administrator

• The Iroha network is running
• The administrator has access to the root account of the network

• At step 2, in case of the invalid genesis block, the Iroha peer shows corresponding error messages to the administrator and halts the network creation process

Use case flow

Use case flow

Use case flow

• The user has an account in the Iroha network
• The user has prepared the transaction for sending; transactions can consist of several instructions
• The user has permissions to execute all instruction included in the transaction
• The Iroha network is working in normal condition

Use case flow

1. The user sends the transaction to the Iroha peer through the API
2. The Iroha peer receives the transaction and validates its contents
3. The Iroha peer checks that the user's account have enough permissions to run all instructions included in the transaction
4. The Iroha peer executes the transaction by applying it to the current block
5. The Iroha peer returns the result of the operation to the user

• The transaction is successfully executed and applied to the network state

• On step 4, if the current user's account is multi-signature, the result of the transaction will be applied to the block-store only when the number of signatures will reach the current quorum value. In other cases, the Iroha peer will return "pending" status as a response on step 5.

• On step 2, one of the instructions has invalid structure, the Iroha peer returns an error message with description to the user and stops the flow
• On step 3, if the user's account does not have required permissions to execute one of the instructions, the Iroha peer returns information about that error and stops the flow
• On step 3, in case of a multi-signature transaction, if the instruction signed using the key pair, which was already used for signing that instruction, the Iroha peer will return "already signed" error status and stop the flow

• The user has permission to create other users

Use case flow

1. The user prepares information about the account that should be created, which includes name, domain, the public key and permissions list
2. The user prepares instruction to send to the Iroha network according to the prepared information
3. The user sends the transaction with the instruction to the Iroha peer (<<include>> FR0100)
4. Tha Iroha peer returns the result of the instruction execution to the user

• The new account in the Iroha network is created

• On step 3, if the account with the provided name or public key already exists in the network, the Iroha peer will return "already exists" error status; user case flow will stop.

Use case flow

• The user has access to his/her account in the Iroha network
• The user's account has permissions to provide grantable permissions

Use case flow

1. The user prepares the instruction to grant one or more permissions to another account
2. The user sends the transaction with the prepared instruction to the Iroha peer (<<includes>> FR0100)
3. The Iroha peer returns the result of the instruction to the user

• The permission was granted to another account

Use case flow

• The user has permissions to execute requested instruction

Use case flow

1. The user prepares the instruction parameters according to his/her needs
2. The user sends the transaction with the instruction into the Iroha peer (<<includes>> FR0100)
3. The user uses the same connection for obtaining the status of the instruction finalization
4. The Iroha peer sends updates about the instruction finalization status to the user
5. The user receives the "successfully finalized" status about the instruction

• The instruction is accepted and finalized in the block-storage
• The user did not spend additional resources for redundant network connections and requests

• At step 4 if the instruction cannot pass the validation, the user would not get the "successfully finalized" status; instead, he/she will get the "invalid instruction" status.
• At step 4 if the network is in "bad" condition, the user would get the "successfully finalized" status eventually, when the network will return in a "good" state.

Use case flow

Use case flow

• The user has permissions to change the list of signatories to the required account
• The user has key pair for adding/deleting a signatory to/from the selected account

Use case flow

1. The user prepares the instruction of adding/deleting signatories for sending
2. The user sends the transaction with the instruction to the Iroha peer (<<include>> FR0100)
3. The user receives the response from the Iroha peer

• List of signatories for the selected account was changed correspondingly

• On step 2, if the signatory with the current key pair exists in the list of signatories in the target account, the Iroha peer will return "already added" error status; use case flow stops.

• There is a multi-signature account in the Iroha network
• The user has access to the one or many key pairs for the multi-signature account
• The current amount of signatures to the multi-signature transaction is lower than a current quorum value

Use case flow

• Amount of signatures in the signed instruction increased by 1 signature
• Signed instruction disappears from the list of pending instructions for the current user's account

• On step 2 the user can select more than one transactions, all of them can be sent on step 4 as a separate requests
• On step 3 the user can sign the transaction by more than one signature, and all of them can be sent as a single request per single transaction on step 4

• The user has permissions to change the conditions for the target multi-signature account

Use case flow

1. The user requests the list of currently configured conditions for the target multi-signature account
2. The user prepared the instruction with the list of conditions to be added/removed
3. The user sends the transaction with the instruction to the Iroha peer (<<include>> FR0100)
4. The Iroha peer sends the response to the user

• The list of conditions for the target multi-signature account was changed correspondingly

Use case flow

Use case flow

Use case flow

• The user has permissions to request the list of pending transactions

Use case flow

• The user has the list of currently pending instructions

• On step 3, if there are no currently pending transactions, the Iroha peer will return "empty response" status

• The user has permissions to request a list of conditions to the target multi-signature account

Use case flow

1. The user prepares query for requesting a list of currently configured conditions of signing for the target multi-signature account
2. The user sends the query to the Iroha peer (<<include>> FR0200)
3. The user receives the list of currently configured conditions of signing for the target multi-signature account

• The user received the list of conditions for the target account

• On step 3, if there are no currently configured conditions, the Iroha peer will return "empty response" status
• On step 3, if the account is not multi-signature, the Iroha peer will return "not applicable" status

• The user has permissions to request the block by its number

Use case flow

• The user has the i-th block

• On step 3, if there are no block specified, the Iroha peer will return "error/no such block" response

• The user has permissions to request blocks (subscription, can be separate permission or from <<include>> FR0205)

Use case flow

• The user has got stable blocks perception channel and newly arriving blocks

• The user has permissions to request the list of pending transactions (subscription, can be separate permission or from <<include>> FR0203)

Use case flow

• The user has got stable pending transactions perception channel and newly arriving pending transactions