fix: Invalid signature integer: negative on JS platform (#158)

Signed-off-by: Francisco Javier Ribó Labrador <[email protected]>
Co-authored-by: Ahmed Moussa <[email protected]>

Author: elribonazo

apollo/src/jsMain/kotlin/io/iohk/atala/prism/apollo/secp256k1/Secp256k1Lib.kt

@@ -67,7 +67,11 @@ actual class Secp256k1Lib actual constructor() {
         } catch (e: dynamic) {
             secp256k1.Signature.fromCompact(jsSignatureByteArray)
         }
-        return signature.normalizeS()
+        return if (signature.hasHighS()) {
+            signature.normalizeS()
+        } else {
+            signature
+        }
     }
 
     /**
@@ -88,8 +92,12 @@ actual class Secp256k1Lib actual constructor() {
         if (secp256k1.verify(normalised, sha.asUint8Array(), publicKey.asUint8Array(), {})) {
             return true
         }
-        val transcoded = transcodeSignatureToBitcoin(normalised.toCompactRawBytes().asByteArray())
-        return secp256k1.verify(transcoded, sha.asUint8Array(), publicKey.asUint8Array(), {})
+        return try {
+            val transcoded = transcodeSignatureToBitcoin(normalised.toCompactRawBytes().asByteArray())
+            secp256k1.verify(transcoded, sha.asUint8Array(), publicKey.asUint8Array(), {})
+        } catch (e: dynamic) {
+            secp256k1.verify(normalised, sha.asUint8Array(), publicKey.asUint8Array(), {})
+        }
     }
 
     private fun transcodeSignatureToBitcoin(signature: ByteArray): SignatureType {

apollo/src/jsTest/kotlin/io/iohk/atala/prism/apollo/utils/Secp256k1LibTestJS.kt

@@ -0,0 +1,24 @@
+package io.iohk.atala.prism.apollo.utils
+
+import io.iohk.atala.prism.apollo.derivation.Mnemonic
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class Secp256k1LibTestJS {
+
+    @Test
+    fun testCreateApolloSignatureAndVerify() {
+        val mnemonics = Mnemonic.Companion.createRandomMnemonics()
+        val seed = Mnemonic.Companion.createSeed(mnemonics)
+        val secret = seed.slice(0..31).toTypedArray()
+        val sk = KMMECSecp256k1PrivateKey.Companion.secp256k1FromByteArray(secret.toByteArray())
+        val pk = sk.getPublicKey()
+        val data = "Data 0002".encodeToByteArray()
+        val signature = sk.sign(data)
+        val verified = pk.verify(signature, data)
+        assertEquals(
+            verified,
+            true
+        )
+    }
+}