diff --git a/modules/openid-federation-client/src/commonTest/kotlin/com/sphereon/oid/fed/client/trustchain/TrustChainTest.kt b/modules/openid-federation-client/src/commonTest/kotlin/com/sphereon/oid/fed/client/trustchain/TrustChainTest.kt
index 37cd66b..218c525 100644
--- a/modules/openid-federation-client/src/commonTest/kotlin/com/sphereon/oid/fed/client/trustchain/TrustChainTest.kt
+++ b/modules/openid-federation-client/src/commonTest/kotlin/com/sphereon/oid/fed/client/trustchain/TrustChainTest.kt
@@ -1,7 +1,9 @@
 package com.sphereon.oid.fed.client.trustchain
 
 import com.sphereon.oid.fed.client.FederationClient
+import com.sphereon.oid.fed.client.crypto.ICryptoService
 import com.sphereon.oid.fed.client.fetch.IFetchService
+import com.sphereon.oid.fed.openapi.models.Jwk
 import kotlinx.coroutines.test.runTest
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -13,10 +15,16 @@ object FetchService : IFetchService {
     }
 }
 
+object CryptoService : ICryptoService {
+    override suspend fun verify(jwt: String, key: Jwk): Boolean {
+        return true
+    }
+}
+
 class TrustChainTest {
     @Test
     fun buildTrustChain() = runTest {
-        val client = FederationClient(FetchService)
+        val client = FederationClient(FetchService, CryptoService)
 
         val trustChain = client.resolveTrustChain(
             "https://spid.wbss.it/Spid/oidc/rp/ipasv_lt",
diff --git a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/Client.js.kt b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/Client.js.kt
index 8577478..41e7307 100644
--- a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/Client.js.kt
+++ b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/Client.js.kt
@@ -1,37 +1,15 @@
+import com.sphereon.oid.fed.client.crypto.CryptoServiceAdapter
 import com.sphereon.oid.fed.client.crypto.ICryptoService
+import com.sphereon.oid.fed.client.crypto.ICryptoServiceJS
 import com.sphereon.oid.fed.client.crypto.cryptoService
+import com.sphereon.oid.fed.client.fetch.FetchServiceAdapter
 import com.sphereon.oid.fed.client.fetch.IFetchService
+import com.sphereon.oid.fed.client.fetch.IFetchServiceJS
 import com.sphereon.oid.fed.client.fetch.fetchService
 import com.sphereon.oid.fed.client.trustchain.TrustChain
-import com.sphereon.oid.fed.openapi.models.Jwk
 import kotlinx.coroutines.*
-import kotlinx.serialization.json.Json
 import kotlin.js.Promise
 
-@JsExport
-@JsName("IFetchService")
-interface IFetchServiceJS {
-    fun fetchStatement(endpoint: String): Promise<String>
-}
-
-@JsExport
-@JsName("ICryptoService")
-interface ICryptoServiceJS {
-    fun verify(data: String, key: String): Promise<Boolean>
-}
-
-class FetchServiceAdapter(private val jsFetchService: IFetchServiceJS) : IFetchService {
-    override suspend fun fetchStatement(endpoint: String): String {
-        return jsFetchService.fetchStatement(endpoint).await()
-    }
-}
-
-class CryptoServiceAdapter(private val jsCryptoService: ICryptoServiceJS) : ICryptoService {
-    override suspend fun verify(jwt: String, key: Jwk): Boolean {
-        return jsCryptoService.verify(jwt, Json.encodeToString(Jwk.serializer(), key)).await()
-    }
-}
-
 @JsExport
 @JsName("FederationClient")
 class FederationClientJS(
diff --git a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/crypto/Crypto.js.kt b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/crypto/Crypto.js.kt
index 834aed3..ea73ef0 100644
--- a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/crypto/Crypto.js.kt
+++ b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/crypto/Crypto.js.kt
@@ -19,12 +19,18 @@ external object Jose {
 external interface ICryptoServiceJS {
     fun verify(
         jwt: String,
-        key: Jwk
+        key: String
     ): Promise<Boolean>
 }
 
+class CryptoServiceAdapter(private val jsCryptoService: ICryptoServiceJS) : ICryptoService {
+    override suspend fun verify(jwt: String, key: Jwk): Boolean {
+        return jsCryptoService.verify(jwt, Json.encodeToString(Jwk.serializer(), key)).await()
+    }
+}
+
 object CryptoServiceJS : ICryptoServiceJS {
-    override fun verify(jwt: String, key: Jwk): Promise<Boolean> {
+    override fun verify(jwt: String, key: String): Promise<Boolean> {
         return Promise { resolve, reject ->
             try {
                 val decodedJwt = decodeJWTComponents(jwt)
@@ -52,7 +58,7 @@ object CryptoServiceJS : ICryptoServiceJS {
 actual fun cryptoService(): ICryptoService {
     return object : ICryptoService {
         override suspend fun verify(jwt: String, key: Jwk): Boolean {
-            return CryptoServiceJS.verify(jwt, key).await()
+            return CryptoServiceJS.verify(jwt, Json.encodeToString(key)).await()
         }
     }
 }
diff --git a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/fetch/Fetch.js.kt b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/fetch/Fetch.js.kt
index 8b0addd..d3c48f3 100644
--- a/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/fetch/Fetch.js.kt
+++ b/modules/openid-federation-client/src/jsMain/kotlin/com/sphereon/oid/fed/client/fetch/Fetch.js.kt
@@ -5,6 +5,20 @@ import io.ktor.client.call.*
 import io.ktor.client.engine.js.*
 import io.ktor.client.request.*
 import io.ktor.http.*
+import kotlinx.coroutines.await
+import kotlin.js.Promise
+
+@JsExport
+@JsName("IFetchService")
+interface IFetchServiceJS {
+    fun fetchStatement(endpoint: String): Promise<String>
+}
+
+class FetchServiceAdapter(private val jsFetchService: IFetchServiceJS) : IFetchService {
+    override suspend fun fetchStatement(endpoint: String): String {
+        return jsFetchService.fetchStatement(endpoint).await()
+    }
+}
 
 actual fun fetchService(): IFetchService {
     return object : IFetchService {