co.topl.crypto.signatures.Curve25519.scala Maven / Gradle / Ivy

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package co.topl.crypto.signatures

import co.topl.crypto.hash.sha256
import co.topl.crypto.{PrivateKey, PublicKey}
import org.whispersystems.curve25519.OpportunisticCurve25519Provider

import java.lang.reflect.Constructor

/* Forked from https://github.com/input-output-hk/scrypto */

object Curve25519 extends EllipticCurveSignatureScheme {

  val SignatureLength25519 = 64
  val KeyLength25519 = 32

  override val SignatureLength = SignatureLength25519
  override val KeyLength = KeyLength25519

  /* todo: dirty hack, switch to logic as described in WhisperSystem's Curve25519 tutorial when
              it would be possible to pass a random seed from outside, see
              https://github.com/WhisperSystems/curve25519-java/pull/7
   */
  private val provider: OpportunisticCurve25519Provider = {
    val constructor = classOf[OpportunisticCurve25519Provider].getDeclaredConstructors.head
      .asInstanceOf[Constructor[OpportunisticCurve25519Provider]]
    constructor.setAccessible(true)
    constructor.newInstance()
  }

  override def createKeyPair(seed: Array[Byte]): (PrivateKey, PublicKey) = {
    val hashedSeed = sha256.hash(seed)
    val privateKey = PrivateKey(provider.generatePrivateKey(hashedSeed.value))
    val publicKey = PublicKey(provider.generatePublicKey(privateKey.value))

    privateKey -> publicKey
  }

  override def createKeyPair: (PrivateKey, PublicKey) = {
    val random = new Array[Byte](KeyLength)
    new java.security.SecureRandom().nextBytes(random)
    val privateKey = PrivateKey(provider.generatePrivateKey(random))
    val publicKey = PublicKey(provider.generatePublicKey(privateKey.value))

    privateKey -> publicKey
  }

  override def sign(privateKey: PrivateKey, message: MessageToSign): Signature = {
    require(privateKey.value.length == KeyLength)
    Signature(provider.calculateSignature(provider.getRandom(SignatureLength), privateKey.value, message))
  }

  override def verify(signature: Signature, message: MessageToSign, publicKey: PublicKey): Boolean =
    signature.value.length == SignatureLength &&
    publicKey.value.length == KeyLength &&
    provider.verifySignature(publicKey.value, message, signature.value)

}