Struct Transaction

pub struct Transaction {
    pub inputs: Vec<DynInput>,
    pub outputs: Vec<DynOutput>,
    pub nonce: [u8; 8],
    pub signatures: TransactionSignature,
}

An atomic value transfer operation within the Fedimint system and consensus

The mint enforces that the total value of the outputs equals the total value of the inputs, to prevent creating funds out of thin air. In some cases, the value of the inputs and outputs can both be 0 e.g. when creating an offer to a Lightning Gateway.

Fields

inputs: Vec<DynInput>

DynInputs consumed by the transaction

outputs: Vec<DynOutput>

DynOutputs created as a result of the transaction

nonce: [u8; 8]

No defined meaning, can be used to send the otherwise exactly same transaction multiple times if the module inputs and outputs don’t introduce enough entropy.

In the future the nonce can be used for grinding a tx hash that fulfills certain PoW requirements.

signatures: TransactionSignature

signatures for all the public keys of the inputs

Implementations

impl Transaction

pub const MAX_TX_SIZE: usize = 49_968usize

Maximum size that a transaction can have while still fitting into an AlephBFT unit. Subtracting 32 bytes is overly conservative, even in the worst case the CI serialization around the transaction should never add that much overhead. But since the byte limit is 50kb right now a few bytes more or less won’t make a difference and we can afford the safety margin.

A realistic value would be 7:

• 1 byte for length of vector of CIs
• 1 byte for the CI enum variant
• 5 byte for the CI enum variant length

pub fn tx_hash(&self) -> TransactionId

Hash of the transaction (excluding the signature).

Transaction signature commits to this hash. To generate it without already having a signature use Self::tx_hash_from_parts.

pub fn tx_hash_from_parts( inputs: &[DynInput], outputs: &[DynOutput], nonce: [u8; 8], ) -> TransactionId

Generate the transaction hash.

pub fn validate_signatures( &self, pub_keys: &[PublicKey], ) -> Result<(), TransactionError>

Validate the schnorr signatures signed over the tx_hash

Trait Implementations

impl Clone for Transaction

fn clone(&self) -> Transaction

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Transaction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Decodable for Transaction

fn consensus_decode_from_finite_reader<D: Read>( d: &mut D, modules: &ModuleDecoderRegistry, ) -> Result<Self, DecodeError>

Decode Self from a size-limited reader.

fn consensus_decode<R: Read>( r: &mut R, modules: &ModuleDecoderRegistry, ) -> Result<Self, DecodeError>

Decode an object with a well-defined format.

fn consensus_decode_hex( hex: &str, modules: &ModuleDecoderRegistry, ) -> Result<Self, DecodeError>

Decode an object from hex

fn consensus_decode_vec( bytes: Vec<u8>, modules: &ModuleDecoderRegistry, ) -> Result<Self, DecodeError>

impl Encodable for Transaction

fn consensus_encode<W: Write>(&self, writer: &mut W) -> Result<usize, Error>

Encode an object with a well-defined format. Returns the number of bytes written on success.

fn consensus_encode_to_vec(&self) -> Vec<u8>

Self::consensus_encode to newly allocated Vec<u8>

fn consensus_encode_to_hex(&self) -> String

Encode and convert to hex string representation

fn consensus_encode_to_len(&self) -> usize

Encode without storing the encoding, return the size

fn consensus_hash<H>(&self) -> H

where H: Hash, H::Engine: Write,

Generate a SHA256 hash of the consensus encoding using the default hash engine for H.

impl Hash for Transaction

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Transaction

fn eq(&self, other: &Transaction) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for Transaction

impl StructuralPartialEq for Transaction