# Terminology¶

Hash of additional data (in addition to a balance proof itself) used on the Raiden protocol (and potentially in the future also the application layer). Currently this is the hash of the off-chain message that contains the balance proof. In the future, for example, some form of payment metadata can be hashed in.
amount
Number of tokens that is referred to in a specific message, e.g. amount in locked transfer means number of tokens to be added to the already locked tokens as part of a transfer
balance data
The data relevant to a channel’s balance: locked amount, transferred amount and locksroot.
balance proof
BP
Signed data required by the Payment Channel to prove the balance of one of the parties. Different formats exist for off-chain communication and on-chain communication. See the on-chain balance proof definition and off-chain balance proof definition.
balance proof update
Signed balance proof with a countersignature. Depending on the message ID, a balance proof update message either shows the second signer’s intention to close the channel (with a closeChannel() call) or submit the balance proof during the settlement period (with an updateNonClosingBalanceProof() call).
Bidirectional Payment Channel
Payment Channel where the roles of Initiator and Target are interchangeable between the channel participants.
canonical identifier
The globally unique identifier of a channel, consisting of the channel identifier, the token network address and the chain id.
Capacity
Current amount of tokens available for a given participant to make transfers. See Protocol Values and Settlement Algorithm Analysis for how this is computed.
chain id
Chain identifier as defined in EIP155.
Challenge Period
Settlement Window
Settle Timeout
The state of a channel after one channel participant closes the channel. During this period the other participant (or any delegate) is able to provide balance proofs by calling updateNonClosingBalanceProof(). This phase is limited for a number of blocks, after which the channel can be settled. The length of the challenge period can be configured when each channel is opened.
Challenge Period Update
Update of the channel state during the Challenge period. The state can be updated either by the non-closing participant, or by a delegate (MS).
channel identifier
Identifier assigned by Token Network to a Payment Channel. Must be unique inside the Token Network contract. See the implementation definition.
cooperative settle proof
Signed data required by the Payment Channel to allow Participants to close and settle a Payment Channel without undergoing through the Settlement Window. See the message definition.
Delivered
Delivered message
A “message received” acknowledgement on the transport layer. It informs the sender that the message was received and persisted. This message provides a weaker guarantee in respect to the Processed message. It can be emulated by a transport layer that guarantees persistence, or it can be sent by the recipient before the received message is processed (therefore it does not matter if the message was successfully processed or not).
Deposit
Amount of token locked in the contract.
expiration
Specific block after which the lock in the locked transfer expires
Fee Model
Total fees for a Mediated Transfer announced by the Raiden Node doing the Transfer.
Hash Time Lock
HTL
An expirable lock locked by a secret.
Hash Time Locked Transfer
Mediated Transfer
A token Transfer composed of multiple HTL transfers.
HTL Transfer
An expirable potentially cancellable Transfer secured by a Hash Time Lock.
HTL Unlock
The action of unlocking a given Hash Time Lock. This is the message used to finalize a transfer once the path is found and the reserve is acknowledged.
Initiator
The node that sends a Payment.
lock expiration
The lock expiration is the highest block_number until which the transfer can be settled.
locked amount
Total amount of tokens locked in all currently pending HTL transfers sent by a channel participant. This amount corresponds to the locksroot of the HTL locks.
Locked Transfer
Locked Transfer message
A message that reserves an amount of tokens for a specific Payment. See Locked Transfer for details.
lockhash
The hash of a lock. sha3_keccack(lock)
locksroot
The hash of the pending locks. To compute this, encode all pending locks in binary, and hash the concatenation using sha3_keccak.
Mediator
A node that mediates a Payment.
Message
Any message sent from one Raiden Node to the other.
Monitoring Service
MS
The service that monitors channel state on behalf of the user and takes an action if the channel is being closed with a balance proof that would violate the agreed on balances. Responsibilities - Watch channels - Delegate closing
MonitoringRequest
A message that is broadcasted from a client to Monitoring Services in order to request channel watching from the MS. The message contains all the necessary information for the MS to carry out a channel update for the user.
Net Balance
Net of balance in a contract. May be negative or positive. Negative for A(B) if A(B) received more tokens than it spent. For example net_balance(A) = transferred_amount(A) - transferred_amount(B)
nonce
Strictly monotonic value used to order off-chain transfers. It starts at 1. It is a balance proof component. The nonce differentiates between older and newer balance proofs that can be sent by a delegate to the Token Network contract and updated through updateNonClosingBalanceProof.
Participants
The two nodes participating in a Payment Channel are called the channel’s participants.
Partner
The other node in a channel. The node with which we have an open Payment Channel.
Pathfinding Service
A centralized path finding service that has a global view on a token network and provides suitable payment paths for Raiden nodes.
payment
The process of sending tokens from one account to another. May be composed of multiple transfers (Direct or HTL). A payment goes from Initiator to Target.
payment channel
An object living on a blockchain that has all the capabilities required to enable secure off-chain payment channels.
PFSCapacityUpdate
A message that is broadcasted from the client to the Pathfinding Services in order to update the channel capacity.
PFSFeeUpdate
A message that is broadcasted from the client to the Pathfinding Services in order to update the mediation fees demanded by the client.
Processed
Processed message
A “Processed” message is used by the recipient when a message, which has to be validated against blockchain data, was successfully processed. This message is only used to confirm the processing of messages which have some blockchain related data, where receiving the message is not sufficient. This message is required even if the transport guarantees durability of the data. It provides a stronger guarantee then a Delivered, therefore it can replace it.
Raiden Channel
The Payment Channel implementation used in Raiden.
Raiden Light Client
A client that does not mediate payments.
Raiden Network
A collection of Token networks.
The node that is receiving a Message.
Refund Transfer
Refund Transfer message
A message for a Transfer seeking a rerouting. When a receiver of a Locked Transfer message gives up reaching the target, they return a Refund Transfer message. The Refund Transfer message locks an amount of tokens in the direction opposite from the previous Locked Transfer allowing the previous hop to retry with a different path.
Reveal Secret
Reveal Secret message
A message that contains the secret that can open a Hash Time Lock. See Reveal Secret for details.
Reveal Timeout
The number of blocks in a channel allowed for learning about a secret being revealed through the blockchain and acting on it.
Secret
A value used as a preimage in a Hash Time Locked Transfer. Its size should be 32 bytes.
Secret Request
A message from the target that asks for the secret of the payment. See Secret Request for details.
secrethash
The hash of a secret. sha3_keccack(secret)
Sender
The node that is sending a Message. The address of the sender can be inferred from the signature.
Settle Expiration
The exact block at which the channel can be settled.
Sleeping Payment
A payment received by a Raiden Light Client that is not online.
Target
The node that receives a Payment.
Token Network
A network of payment channels for a given Token.
The ethereum address on which the contract representing a token network is deployed. It serves as the identifier of the token network and as part of the canonical identifier of channels within the token network.
Token Swaps
Exchange of one token for another.
Transfer
A movement of tokens from a Sender to a Receiver.
Transferred amount
Monotonically increasing amount of tokens transferred from one Raiden node to another. It represents all the finalized transfers. For the pending transfers, check locked amount.
Unidirectional Payment Channel
Payment Channel where the roles of Initiator and Target are determined in the channel creation and cannot be changed.
Unlock
Unlock message
A message that contains a new balance proof after a Hash Time Lock is unlocked. See Unlock for details.
withdraw proof
Participant Withdraw Proof
Signed data required by the Payment Channel to allow a participant to withdraw tokens. See the message definition.