Secure random for JS

.github/workflows/ci.yml

@@ -103,7 +103,7 @@ jobs:
           key: ${{ runner.os }}-sbt-cache-v2-${{ hashFiles('**/*.sbt') }}-${{ hashFiles('project/build.properties') }}
 
       - name: Runs tests and collect coverage
-        run: sbt -jvm-opts ci/ci.jvmopts ++${{ matrix.scala }} commonJS/test corelibJS/test interpreterJS/test graphirJS/test sdkJS/test
+        run: sbt -jvm-opts ci/ci.jvmopts ++${{ matrix.scala }} commonJS/test corelibJS/test interpreterJS/test graphirJS/test sdkJS/test scJS/test
 
       - name: Publish a JVM snapshot ${{ github.ref }}
         if: env.HAS_SECRETS == 'true'

build.sbt

@@ -186,7 +186,7 @@ lazy val commonDependenies2 = libraryDependencies ++= Seq(
   "org.scala-lang.modules" %%% "scala-collection-compat" % "2.7.0"
 )
 
-val sigmajsCryptoFacadeVersion = "0.0.6"
+val sigmajsCryptoFacadeVersion = "0.0.7"
 
 lazy val common = crossProject(JVMPlatform, JSPlatform)
   .in(file("common"))

interpreter/js/src/main/scala/sigmastate/crypto/Platform.scala

@@ -100,14 +100,23 @@ object Platform {
   def multiplyPoints(p1: Ecp, p2: Ecp): Ecp = new Ecp(CryptoFacadeJs.addPoint(p1.point, p2.point))
 
   /** Exponentiate a point p.
+    * The implementation mimics the Java implementation of `AbstractECMultiplier.multiply`
+    * from BouncyCastle library.
     *
     * @param p point to exponentiate
     * @param n exponent
     * @return p to the power of n (`p^n`) i.e. `p + p + ... + p` (n times)
     */
   def exponentiatePoint(p: Ecp, n: BigInteger): Ecp = {
-    val scalar = Convert.bigIntegerToBigInt(n)
-    new Ecp(CryptoFacadeJs.multiplyPoint(p.point, scalar))
+    val sign = n.signum()
+    if (sign == 0 || isInfinityPoint(p)) {
+      val ctx = new CryptoContextJs()
+      return new Ecp(ctx.getInfinity())
+    }
+    val scalar = Convert.bigIntegerToBigInt(n.abs())
+    val positive = CryptoFacadeJs.multiplyPoint(p.point, scalar)
+    val result = if (sign > 0) positive else CryptoFacadeJs.negatePoint(positive)
+    new Ecp(result)
   }
 
   /** Check if a point is infinity. */
@@ -120,7 +129,7 @@ object Platform {
   class Curve
 
   // TODO JS: Use JS library for secure source of randomness
-  type SecureRandom = Random
+  type SecureRandom = sigmastate.crypto.SecureRandomJS
 
   /** Opaque point type. */
   @js.native
@@ -198,7 +207,7 @@ object Platform {
   }
 
   /** Create JS specific source of secure randomness. */
-  def createSecureRandom(): Random = new Random()
+  def createSecureRandom(): SecureRandom = new SecureRandomJS
 
   /** Computes HMAC-SHA512 hash of the given data using the specified key.
     *

interpreter/js/src/main/scala/sigmastate/crypto/SigmaJsCryptoFacade.scala

@@ -1,5 +1,7 @@
 package sigmastate.crypto
 
+import debox.cfor
+
 import scala.scalajs.js
 import scala.scalajs.js.annotation.JSImport
 import scala.scalajs.js.typedarray.Uint8Array
@@ -109,6 +111,25 @@ object CryptoFacadeJs extends js.Object {
   def generatePbkdf2Key(
       normalizedMnemonic: String,
       normalizedPass: String): Uint8Array = js.native
+
+  /** Creates a random array of bytes of the given length. */
+  def getRandomBytes(length: Int): Uint8Array = js.native
+}
+
+/** This class provides a cryptographically strong generator of byte arrays. */
+class SecureRandomJS {
+  /**
+    * Generates a user-specified number of random bytes.
+    *
+    * @param bytes the array to be filled in with random bytes.
+    */
+  def nextBytes(bytes: Array[Byte]): Unit = {
+    val len = bytes.length
+    val arr = CryptoFacadeJs.getRandomBytes(len)
+    cfor(0)(_ < len, _ + 1) { i =>
+      bytes(i) = arr(i).toByte
+    }
+  }
 }
 
 /** Represents imported Point class from `sigmajs-crypto-facade` JS libarary. */

sc/shared/src/test/scala/sigmastate/utxo/examples/OracleExamplesSpecification.scala

@@ -15,7 +15,7 @@ import sigmastate.helpers.TestingHelpers._
 import org.ergoplatform._
 import org.ergoplatform.dsl.{ContractSpec, SigmaContractSyntax, StdContracts, TestContractSpec}
 import sigmastate.basics.CryptoConstants
-import sigmastate.crypto.CryptoFacade
+import sigmastate.crypto.{BigIntegers, CryptoFacade}
 import sigmastate.eval.Extensions.ArrayOps
 import sigmastate.interpreter.Interpreter.{ScriptNameProp, emptyEnv}
 import sigmastate.utxo._
@@ -89,7 +89,8 @@ class OracleExamplesSpecification extends CompilerTestingCommons
 
     val temperature: Long = 18
 
-    val r = BigInt.apply(128, CryptoFacade.createSecureRandom()) //128 bits random number
+    //create 128 bits random number
+    val r = BigInt(BigIntegers.createRandomBigInteger(128, CryptoFacade.createSecureRandom()))
     val a = group.exponentiate(group.generator, r.bigInteger)
 
     val ts = System.currentTimeMillis()