40 lines
1.3 KiB
JavaScript
40 lines
1.3 KiB
JavaScript
const { toBN } = require('web3-utils')
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const { encrypt, decrypt } = require('eth-sig-util')
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const { randomBN, poseidonHash } = require('./utils')
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class Account {
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constructor({ amount, secret, nullifier } = {}) {
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this.amount = amount ? toBN(amount) : toBN('0')
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this.secret = secret ? toBN(secret) : randomBN(31)
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this.nullifier = nullifier ? toBN(nullifier) : randomBN(31)
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this.commitment = poseidonHash([this.amount, this.secret, this.nullifier])
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this.nullifierHash = poseidonHash([this.nullifier])
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if (this.amount.lt(toBN(0))) {
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throw new Error('Cannot create an account with negative amount')
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}
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}
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encrypt(pubkey) {
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const bytes = Buffer.concat([
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this.amount.toBuffer('be', 31),
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this.secret.toBuffer('be', 31),
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this.nullifier.toBuffer('be', 31),
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])
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return encrypt(pubkey, { data: bytes.toString('base64') }, 'x25519-xsalsa20-poly1305')
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}
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static decrypt(privkey, data) {
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const decryptedMessage = decrypt(data, privkey)
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const buf = Buffer.from(decryptedMessage, 'base64')
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return new Account({
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amount: toBN('0x' + buf.slice(0, 31).toString('hex')),
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secret: toBN('0x' + buf.slice(31, 62).toString('hex')),
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nullifier: toBN('0x' + buf.slice(62, 93).toString('hex')),
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})
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}
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}
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module.exports = Account
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