72 lines
2.1 KiB
TypeScript
72 lines
2.1 KiB
TypeScript
import { BigNumber } from 'ethers'
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import { numbers, BG_ZERO } from '@/constants'
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import { UtxoStatic, BaseUtxo, BaseKeypair, UtxoOptions } from './@types'
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import { Keypair } from './keypair'
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import { randomBN, poseidonHash, toBuffer } from './utils'
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const BYTES_31 = 31
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const BYTES_62 = 62
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class Utxo extends UtxoStatic implements BaseUtxo {
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public keypair: BaseKeypair
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public amount: BigNumber
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public transactionHash?: string
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public blinding: BigNumber
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public index: number
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public commitment?: BigNumber
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public nullifier?: BigNumber
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public static decrypt(keypair: BaseKeypair, data: string, index: number): BaseUtxo {
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const buf = keypair.decrypt(data)
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return new Utxo({
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amount: BigNumber.from('0x' + buf.slice(numbers.ZERO, BYTES_31).toString('hex')),
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blinding: BigNumber.from('0x' + buf.slice(BYTES_31, BYTES_62).toString('hex')),
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keypair,
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index,
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})
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}
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public constructor({
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amount = BG_ZERO,
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keypair = new Keypair(),
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blinding = randomBN(),
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index = numbers.ZERO,
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}: UtxoOptions = {}) {
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super()
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this.amount = BigNumber.from(amount)
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this.blinding = BigNumber.from(blinding)
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this.keypair = keypair
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this.index = index
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}
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public getCommitment() {
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if (this.commitment == null) {
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this.commitment = poseidonHash([this.amount, this.keypair.pubkey, this.blinding])
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}
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return this.commitment
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}
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public getNullifier() {
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if (this.nullifier == null) {
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// eslint-disable-next-line eqeqeq
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if (this.amount.gt(numbers.ZERO) && (this.index == undefined || this.keypair.privkey == undefined)) {
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throw new Error('Can not compute nullifier without utxo index or shielded key')
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}
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const signature = this.keypair.privkey ? this.keypair.sign(this.getCommitment(), this.index || numbers.ZERO) : numbers.ZERO
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this.nullifier = poseidonHash([this.getCommitment(), this.index || numbers.ZERO, signature])
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}
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return this.nullifier
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}
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public encrypt() {
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const bytes = Buffer.concat([toBuffer(this.amount, BYTES_31), toBuffer(this.blinding, BYTES_31)])
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return this.keypair.encrypt(bytes)
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}
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}
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export { Utxo }
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