Crate xand_ledger

This crate defines our domain models and logic for the xand ledger. IE: This is the code that determines how transactions are validated/processed, as well as the shape of those transactions. It is free of major dependencies and should remain so to provide a clean environment for concentrating on domain code.

Practically speaking this code is consumed in other places for two purposes:

• Validating transactions (within the substrate runtime)
• Constructing transactions (everywhere else)

The crate has an std feature that is enabled by default. Disabling the feature allows the crate to compile in no-std mode. The substrate runtime requires this, and no-std support must be maintained.

Re-exports

• pub use curve25519_dalek;

Modules

• crypto
  Zero Knowledge Implementation
• esig_payload
• verifiable_encryption

Structs

• CashConfirmationTransaction
  Issued by the trust to confirm a pending create request
• ClearRedeemOutput
• ClearRedeemRequestTransaction
  A clear (non-confidential) redeem request transaction
• ClearTransactionOutput
• CompactEncryptedSigner
  Compact representation of the verifiable signer encryption. Useful to store the encrypted values after proofs have already been verified.
• ConfidentialRedeemRequestRecord
• CoreCreateRequestTransaction
  Encapsulates all the fields of the create request transaction except the signature.
• CoreExitingRedeemRequestTransaction
  Encapsulates all the details of a ExitingRedeemRequestTransaction other than the proof with signature.
• CoreRedeemRequestTransaction
  Encapsulates all the details of a RedeemRequestTransaction other than the proof with signature.
• CoreSendClaimsTransaction
  The CoreTransaction contains all the details of a Transaction except the signature and proof. A serialized version of the CoreTransaction is then signed as part of the main proof. A Transaction contains a CoreTransaction and a proof cum signature.
• CreateCancellationTransaction
  Issued by the trust (or intrinsically) to cancel an outstanding create request
• CreateRequestProcessor
  A collection of repositories that when combined are capable of processing create requests, and implement CreateRequestHandler
• CreateRequestRecord
  A record of a confidential pending create request - a user does not submit this directly, rather it is created and stored as a result of processing a create request transaction.
• CreateRequestTransaction
  A create request, as issued by a member
• CreateRequestTxnInputs
  All the (nonrandom) inputs required to construct a CreateRequestTransaction
• CurveVector
• Encrypted
• EncryptionKey
  A Encryption key representing the public portion of some private key, and hence a (potential) sender or receiver of encrypted messages.
• ExitingRedeemOutput
• ExitingRedeemRequestProcessor
• ExitingRedeemRequestTransaction
  An exiting redeem request transaction
• IdentityTag
  An piece of info that identifies an entity as a verified participant. Each (applicable) transaction must include one such valid tag (mixed among decoys).
• InvalidCancellationReason
• KeyImage
  There is a unique key-image for every TransactionOutput, but the key-image cannot be efficiently matched with the corresponding TransactionOutput by any polynomial time probabilistic algorithm with a non-negligible probability without using the private key. If a Transaction contains a key-image that has already been used, then the corresponding TransactionOutput has been spent already, which means that the transaction is invalid.
• Milliseconds
  Milliseconds - often used as millis since epoch to form a timestamp
• MonetaryValue
• NotAPublicKey
  Error type specifying that a public key cannot be derived from Identity Tag
• OneTimeKey
  Represents a public key that is specific to an individual txo
• OpenedTransactionOutput
  An OpenedTransactionOutput represents a UTXO and the information needed to reveal/open it.
• PrivateExitingRedeemRequestInputs
  Inputs for a participant issuing an exiting redeem request
• PrivateInputs
• PrivateRedeemRequestInputs
  Inputs for a participant issuing a redeem request
• Proof
• PublicInputSet
• PublicKey
  A cryptographic public key representing a public identity
• RedeemCancellationTransaction
  Issued by the trust (or intrinsically) to cancel an outstanding redeem request
• RedeemFulfillmentTransaction
  Issued by the trust to confirm a redeem fulfillment
• RedeemOutput
• RedeemRequestProcessor
• RedeemRequestTransaction
  A redeem request transaction
• RewardProcessor
• SendClaimsOutput
  Transfer TxO and associated data
• SendClaimsProcessor
• SendClaimsTransaction
  A send claims transaction representing the transfer of value from one registered member to another
• SpendingOutput
• TransactionInputSet
  A collection of TransactionOutput(s). The are used in a transaction as a collection of inputs that are summed up to make the total value of the transaction. A transaction includes multiple TransactionInputSets, only one of which is the real TransactionInputSet being spent.
• TransactionOutput
  A transaction output, or TXO, represents a commitment to some value, and information about who owns the right to spend that value (claims).
• VectorTuple
• VerifiableEncryptionOfSignerKey

Enums

• BannedState
  State of banned member
• CorrelationIdUsedBy
  Expresses reasons a correlation id is already used. Is returned by CorrelationIdRepository::is_used
• CreateCancellationReason
  The reason a create request was cancelled
• EncryptionKeyError
• FailureReason
  Failures that may occur during transaction validation
• LedgerTransaction
  All transactions in xand_ledger
• MonetaryValueError
• RedeemCancellationReason
  The reason a redeem request was cancelled
• RedeemSigner
• TransactionBuilderErrors
• TransactionValidationError
• TxoStatus
  The status of a TransactionOutput
• ZkPlmtError

Traits

• BlockInfoRepository
  Provides access to info about the currently executing/processing block
• CashConfirmationHandler
  Implementors are capable of processing cash confirmation transactions
• ClearRedeemRequestHandler
  Implementors are capable of processing clear redeem request transactions
• ClearTransactionOutputRepository
  Provides access to information stored in the ledger regarding ClearTransactionOutputs
• CorrelationIdRepository
  Provides access to information stored in the ledger regarding CorrelationIds
• CreateCancellationHandler
  Implementors are capable of processing create cancellation transactions
• CreateRequestHandler
  Implementors are capable of processing create request transactions
• CreateRequestRepository
  Provides access to and storage of info in the ledger about pending create requests in the form of CreateRequestRecords
• DecryptSigner
• Dispatcher
  A dispatcher is capable of accepting transactions and executing them. This functionality is important because sometimes you would like a transaction to “happen” as a result of processing another transaction, or simply periodically (ex: every block). This mechanism allows us to ensure the other transaction is counted as a proper transaction - and not just an identical modification of state (IE: It shows up as it’s own transaction in the block).
• ExitingRedeemRequestHandler
• IUtxo
• IdentityTagRepository
  Provides access to information stored in the ledger regarding IdentityTags
• KeyImageRepository
  Provides access to information stored in the ledger regarding KeyImages
• MemberRepository
  Trait for managing the storage of member data
• PendingCreateRequestExpireTime
  Provides access to configurable expiration time for pending create requests
• RedeemCancellationHandler
  Implementors are capable of processing redeem cancellation transactions
• RedeemFulfillmentHandler
  Implementors are capable of processing redeem fulfillment transactions
• RedeemRequestHandler
  Implementors are capable of processing redeem request transactions
• RedeemRequestRepository
  Provides access to and storage of info in the ledger about pending unfulfilled redeem requests in the form of RedeemRequestRecords
• RewardTransactionHandler
  Implementors are capable of processing reward transactions
• SendClaimsHandler
  Implementors are capable of processing send claims transactions
• TotalIssuanceRepository
  Trait for tracking the current total number of claims
• TransactionDataRepository
  Provides access to information stored in the ledger regarding TransactionOutputs
• TrustMetadata
  Provides access to the metadata about the trust. Specifically, it gives access to the public key of the trust.
• ValidatorRepository
  Trait for managing the storage of validator data

Functions

• check_identity_tag_ownership
  Returns whether the identity tag matches the private key
• check_txo_ownership
  Given a TransactionOutput, check whether it is owned by the private key provided.
• construct_clear_redeem_request_transaction
• construct_create_request_transaction
  Builds a create request
• construct_exiting_redeem_request_transaction
• construct_redeem_request_transaction
• construct_send_claims_transaction
• decode_one_time_key
  Determine the PublicKey associated with a given OneTimeKey. The OneTimeKey is derived using the message body, the txo index, and the message sender’s private key to form a random value that is only reproducible for the sender.
• find_secret_input_index
  Find row in inputs that matches the given key_images and private_key.

Type Definitions

• BlockNumber
  A block number
• ClearRedeemRequestRecord
• CorrelationId
  A unique identifier to associate an on-chain transaction with some real-world event, for now, a cash transfer at a Xand-Enabled Bank.
• EncryptedBlob
  Some blob of binary data that has been encrypted
• PrivateKey
  A private key, as held by a transaction signer / creator.
• RedeemRequestRecord
• RewardTransaction
• Salt
• TransactionResult
  The result of processing/validating a transaction