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package net.taler.wallet.kotlin.crypto
import net.taler.wallet.kotlin.Amount
import net.taler.wallet.kotlin.Base32Crockford
internal class Planchet(private val crypto: Crypto) {
data class CreationRequest(
val value: Amount,
val feeWithdraw: Amount,
val denomPub: String,
val reservePub: String,
val reservePriv: String
)
data class CreationResult(
val coinPub: String,
val coinPriv: String,
val reservePub: String,
val denomPubHash: String,
val denomPub: String,
val blindingKey: String,
val withdrawSig: String,
val coinEv: String,
val coinValue: Amount,
val coinEvHash: String
)
internal fun create(req: CreationRequest, coinKeyPair: EddsaKeyPair, blindingFactor: ByteArray): CreationResult {
val reservePub = Base32Crockford.decode(req.reservePub)
val reservePriv = Base32Crockford.decode(req.reservePriv)
val denomPub = Base32Crockford.decode(req.denomPub)
val coinPubHash = crypto.sha512(coinKeyPair.publicKey)
val ev = crypto.rsaBlind(coinPubHash, blindingFactor, denomPub)
val amountWithFee = req.value + req.feeWithdraw
val denomPubHash = crypto.sha512(denomPub)
val evHash = crypto.sha512(ev)
val withdrawRequest = Signature.PurposeBuilder(Signature.RESERVE_WITHDRAW)
.put(reservePub)
.put(amountWithFee.toByteArray())
.put(req.feeWithdraw.toByteArray())
.put(denomPubHash)
.put(evHash)
.build()
val sig = crypto.eddsaSign(withdrawRequest, reservePriv)
return CreationResult(
blindingKey = Base32Crockford.encode(blindingFactor),
coinEv = Base32Crockford.encode(ev),
coinPriv = Base32Crockford.encode(coinKeyPair.privateKey),
coinPub = Base32Crockford.encode(coinKeyPair.publicKey),
coinValue = req.value,
denomPub = req.denomPub,
denomPubHash = Base32Crockford.encode(denomPubHash),
reservePub = req.reservePub,
withdrawSig = Base32Crockford.encode(sig),
coinEvHash = Base32Crockford.encode(evHash)
)
}
/**
* Create a pre-coin ([Planchet]) of the given [CreationRequest].
*/
fun create(req: CreationRequest): CreationResult {
val coinKeyPair = crypto.createEddsaKeyPair()
val blindingFactor = crypto.getRandomBytes(32)
return create(req, coinKeyPair, blindingFactor)
}
}
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