diff --git a/lib/wallet/cryptoApi.ts b/lib/wallet/cryptoApi.ts
index ec20dd964..88b82ae3b 100644
--- a/lib/wallet/cryptoApi.ts
+++ b/lib/wallet/cryptoApi.ts
@@ -28,11 +28,6 @@ import {CoinWithDenom} from "./wallet";
 import {PayCoinInfo} from "./types";
 import {RefreshSession} from "./types";
 
-interface RegistryEntry {
-  resolve: any;
-  reject: any;
-  workerIndex: number;
-}
 
 interface WorkerState {
   /**
@@ -41,19 +36,14 @@ interface WorkerState {
   w: Worker|null;
 
   /**
-   * Are we currently running a task on this worker?
+   * Work we're currently executing or null if not busy.
    */
-  busy: boolean;
+  currentWorkItem: WorkItem|null;
 
   /**
    * Timer to terminate the worker if it's not busy enough.
    */
   terminationTimerHandle: number|null;
-
-  /**
-   * Index of this worker in the list of workers.
-   */
-  workerIndex: number;
 }
 
 interface WorkItem {
@@ -61,6 +51,11 @@ interface WorkItem {
   args: any[];
   resolve: any;
   reject: any;
+
+  /**
+   * Serial id to identify a matching response.
+   */
+  rpcId: number;
 }
 
 
@@ -72,27 +67,21 @@ const NUM_PRIO = 5;
 
 export class CryptoApi {
   private nextRpcId: number = 1;
-  private rpcRegistry: {[n: number]: RegistryEntry} = {};
   private workers: WorkerState[];
   private workQueues: WorkItem[][];
   /**
    * Number of busy workers.
    */
   private numBusy: number = 0;
-  /**
-   * Number if pending work items.
-   */
-  private numWaiting: number = 0;
-
 
   /**
    * Start a worker (if not started) and set as busy.
    */
-  wake(ws: WorkerState) {
-    if (ws.busy) {
+  wake<T>(ws: WorkerState, work: WorkItem): void {
+    if (ws.currentWorkItem != null) {
       throw Error("assertion failed");
     }
-    ws.busy = true;
+    ws.currentWorkItem = work;
     this.numBusy++;
     if (!ws.w) {
       let w = new Worker("/lib/wallet/cryptoWorker.js");
@@ -100,27 +89,45 @@ export class CryptoApi {
       w.onerror = (e: ErrorEvent) => this.handleWorkerError(ws, e);
       ws.w = w;
     }
+
+    let msg: any = {
+      operation: work.operation, args: work.args,
+      id: work.rpcId
+    };
+    this.resetWorkerTimeout(ws);
+    ws.w!.postMessage(msg);
+  }
+
+  resetWorkerTimeout(ws: WorkerState) {
     if (ws.terminationTimerHandle != null) {
       clearTimeout(ws.terminationTimerHandle);
     }
     let destroy = () => {
-      if (ws.w && !ws.busy) {
+      // terminate worker if it's idle
+      if (ws.w && ws.currentWorkItem == null) {
         ws.w!.terminate();
         ws.w = null;
       }
-    }
+    };
     ws.terminationTimerHandle = setTimeout(destroy, 20 * 1000);
   }
 
   handleWorkerError(ws: WorkerState, e: ErrorEvent) {
-    console.error("error in worker", e);
+    if (ws.currentWorkItem) {
+      console.error(`error in worker during ${ws.currentWorkItem!.operation}`, e);
+    } else {
+      console.error("error in worker", e);
+    }
+    console.error(e.message);
     try {
       ws.w!.terminate();
+      ws.w = null;
     } catch (e) {
       console.error(e);
     }
-    if (ws.busy) {
-      ws.busy = false;
+    if (ws.currentWorkItem != null) {
+      ws.currentWorkItem.reject(e);
+      ws.currentWorkItem = null;
       this.numBusy--;
     }
     this.findWork(ws);
@@ -132,14 +139,7 @@ export class CryptoApi {
       let q = this.workQueues[NUM_PRIO - i - 1];
       if (q.length != 0) {
         let work: WorkItem = q.shift()!;
-        let msg: any = {
-          operation: work.operation,
-          args: work.args,
-          id: this.registerRpcId(work.resolve, work.reject, ws.workerIndex),
-        };
-
-        this.wake(ws);
-        ws.w!.postMessage(msg);
+        this.wake(ws, work);
         return;
       }
     }
@@ -151,22 +151,19 @@ export class CryptoApi {
       console.error("rpc id must be number");
       return;
     }
-    if (!this.rpcRegistry[id]) {
+    let currentWorkItem = ws.currentWorkItem;
+    ws.currentWorkItem = null;
+    this.numBusy--;
+    this.findWork(ws);
+    if (!currentWorkItem) {
+      console.error("unsolicited response from worker");
+      return;
+    }
+    if (id != currentWorkItem.rpcId) {
       console.error(`RPC with id ${id} has no registry entry`);
       return;
     }
-    let {resolve, workerIndex} = this.rpcRegistry[id];
-    delete this.rpcRegistry[id];
-    if (workerIndex != ws.workerIndex) {
-      throw Error("assertion failed");
-    }
-    if (!ws.busy) {
-      throw Error("assertion failed");
-    }
-    ws.busy = false;
-    this.numBusy--;
-    resolve(msg.data.result);
-    this.findWork(ws);
+    currentWorkItem.resolve(msg.data.result);
   }
 
   constructor() {
@@ -175,9 +172,8 @@ export class CryptoApi {
     for (let i = 0; i < this.workers.length; i++) {
       this.workers[i] = {
         w: null,
-        busy: false,
         terminationTimerHandle: null,
-        workerIndex: i,
+        currentWorkItem: null,
       };
     }
     this.workQueues = [];
@@ -186,45 +182,34 @@ export class CryptoApi {
     }
   }
 
-
-  private registerRpcId(resolve: any, reject: any,
-                        workerIndex: number): number {
-    let id = this.nextRpcId++;
-    this.rpcRegistry[id] = {resolve, reject, workerIndex};
-    return id;
-  }
-
-
   private doRpc<T>(operation: string, priority: number,
                    ...args: any[]): Promise<T> {
-    if (this.numBusy == this.workers.length) {
-      let q = this.workQueues[priority];
-      if (!q) {
-        throw Error("assertion failed");
-      }
-      return new Promise<T>((resolve, reject) => {
-        this.workQueues[priority].push({operation, args, resolve, reject});
-      });
-    }
 
-    for (let i = 0; i < this.workers.length; i++) {
-      let ws = this.workers[i];
-      if (ws.busy) {
-        continue;
+    return new Promise((resolve, reject) => {
+      let rpcId = this.nextRpcId++;
+      let workItem: WorkItem = {operation, args, resolve, reject, rpcId};
+
+      if (this.numBusy == this.workers.length) {
+        let q = this.workQueues[priority];
+        if (!q) {
+          throw Error("assertion failed");
+        }
+        this.workQueues[priority].push(workItem);
+        return;
       }
 
-      this.wake(ws);
+      for (let i = 0; i < this.workers.length; i++) {
+        let ws = this.workers[i];
+        if (ws.currentWorkItem != null) {
+          continue;
+        }
 
-      return new Promise<T>((resolve, reject) => {
-        let msg: any = {
-          operation, args,
-          id: this.registerRpcId(resolve, reject, i),
-        };
-        ws.w!.postMessage(msg);
-      });
-    }
+        this.wake<T>(ws, workItem);
+        return;
+      }
 
-    throw Error("assertion failed");
+      throw Error("assertion failed");
+    });
   }
 
 
@@ -270,4 +255,4 @@ export class CryptoApi {
                       meltAmount,
                       meltFee);
   }
-}
+}
\ No newline at end of file
diff --git a/lib/wallet/cryptoLib.ts b/lib/wallet/cryptoLib.ts
index 7969682b4..d471b577d 100644
--- a/lib/wallet/cryptoLib.ts
+++ b/lib/wallet/cryptoLib.ts
@@ -79,9 +79,13 @@ namespace RpcFunctions {
     let coinPub = coinPriv.getPublicKey();
     let blindingFactor = native.RsaBlindingKeySecret.create();
     let pubHash: native.HashCode = coinPub.hash();
-    let ev: native.ByteArray = native.rsaBlind(pubHash,
-                                               blindingFactor,
-                                               denomPub);
+    let ev = native.rsaBlind(pubHash,
+                             blindingFactor,
+                             denomPub);
+
+    if (!ev) {
+      throw Error("couldn't blind (malicious exchange key?)");
+    }
 
     if (!denom.fee_withdraw) {
       throw Error("Field fee_withdraw missing");
@@ -234,10 +238,10 @@ namespace RpcFunctions {
   }
 
 
-  function createWithdrawSession(kappa: number, meltCoin: Coin,
-                                 newCoinDenoms: Denomination[],
-                                 meltAmount: AmountJson,
-                                 meltFee: AmountJson): RefreshSession {
+  export function createWithdrawSession(kappa: number, meltCoin: Coin,
+                                        newCoinDenoms: Denomination[],
+                                        meltAmount: AmountJson,
+                                        meltFee: AmountJson): RefreshSession {
 
     let sessionHc = new HashContext();
 
@@ -268,9 +272,12 @@ namespace RpcFunctions {
         let blindingFactor = native.RsaBlindingKeySecret.create();
         let pubHash: native.HashCode = coinPub.hash();
         let denomPub = native.RsaPublicKey.fromCrock(newCoinDenoms[i].denom_pub);
-        let ev: native.ByteArray = native.rsaBlind(pubHash,
-                                                   blindingFactor,
-                                                   denomPub);
+        let ev = native.rsaBlind(pubHash,
+                                 blindingFactor,
+                                 denomPub);
+        if (!ev) {
+          throw Error("couldn't blind (malicious exchange key?)");
+        }
         let preCoin: RefreshPreCoin = {
           blindingKey: blindingFactor.toCrock(),
           coinEv: ev.toCrock(),
diff --git a/lib/wallet/cryptoWorker.ts b/lib/wallet/cryptoWorker.ts
index 4483c64e6..22feb8eb7 100644
--- a/lib/wallet/cryptoWorker.ts
+++ b/lib/wallet/cryptoWorker.ts
@@ -22,7 +22,7 @@
 "use strict";
 
 
-importScripts("../emscripten/libwrapper.js",
+importScripts("../emscripten/taler-emscripten-lib.js",
               "../vendor/system-csp-production.src.js");
 
 
@@ -46,7 +46,7 @@ if ("object" !== typeof Module) {
 
 {
   let mod = System.newModule({Module: Module});
-  let modName = System.normalizeSync("../emscripten/emsc");
+  let modName = System.normalizeSync("../emscripten/taler-emscripten-lib");
   console.log("registering", modName);
   System.set(modName, mod);
 }
diff --git a/lib/wallet/emscriptif.ts b/lib/wallet/emscriptif.ts
index 7c08fdc45..bad1a4c5e 100644
--- a/lib/wallet/emscriptif.ts
+++ b/lib/wallet/emscriptif.ts
@@ -14,13 +14,13 @@
  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
  */
 
-import { AmountJson } from "./types";
-import * as EmscWrapper from "../emscripten/emsc";
+import {AmountJson} from "./types";
+import * as EmscWrapper from "../emscripten/taler-emscripten-lib";
 
 /**
  * High-level interface to emscripten-compiled modules used
  * by the wallet.
- * 
+ *
  * @author Florian Dold
  */
 
@@ -43,82 +43,82 @@ let getEmsc: EmscWrapper.EmscFunGen = (...args: any[]) => Module.cwrap.apply(
 var emsc = {
   free: (ptr: number) => Module._free(ptr),
   get_value: getEmsc('TALER_WR_get_value',
-    'number',
-    ['number']),
+                     'number',
+                     ['number']),
   get_fraction: getEmsc('TALER_WR_get_fraction',
-    'number',
-    ['number']),
+                        'number',
+                        ['number']),
   get_currency: getEmsc('TALER_WR_get_currency',
-    'string',
-    ['number']),
+                        'string',
+                        ['number']),
   amount_add: getEmsc('TALER_amount_add',
-    'number',
-    ['number', 'number', 'number']),
+                      'number',
+                      ['number', 'number', 'number']),
   amount_subtract: getEmsc('TALER_amount_subtract',
-    'number',
-    ['number', 'number', 'number']),
+                           'number',
+                           ['number', 'number', 'number']),
   amount_normalize: getEmsc('TALER_amount_normalize',
-    'void',
-    ['number']),
+                            'void',
+                            ['number']),
   amount_get_zero: getEmsc('TALER_amount_get_zero',
-    'number',
-    ['string', 'number']),
+                           'number',
+                           ['string', 'number']),
   amount_cmp: getEmsc('TALER_amount_cmp',
-    'number',
-    ['number', 'number']),
+                      'number',
+                      ['number', 'number']),
   amount_hton: getEmsc('TALER_amount_hton',
-    'void',
-    ['number', 'number']),
+                       'void',
+                       ['number', 'number']),
   amount_ntoh: getEmsc('TALER_amount_ntoh',
-    'void',
-    ['number', 'number']),
+                       'void',
+                       ['number', 'number']),
   hash: getEmsc('GNUNET_CRYPTO_hash',
-    'void',
-    ['number', 'number', 'number']),
+                'void',
+                ['number', 'number', 'number']),
   memmove: getEmsc('memmove',
-    'number',
-    ['number', 'number', 'number']),
+                   'number',
+                   ['number', 'number', 'number']),
   rsa_public_key_free: getEmsc('GNUNET_CRYPTO_rsa_public_key_free',
-    'void',
-    ['number']),
+                               'void',
+                               ['number']),
   rsa_signature_free: getEmsc('GNUNET_CRYPTO_rsa_signature_free',
-    'void',
-    ['number']),
+                              'void',
+                              ['number']),
   string_to_data: getEmsc('GNUNET_STRINGS_string_to_data',
-    'number',
-    ['number', 'number', 'number', 'number']),
+                          'number',
+                          ['number', 'number', 'number', 'number']),
   eddsa_sign: getEmsc('GNUNET_CRYPTO_eddsa_sign',
-    'number',
-    ['number', 'number', 'number']),
+                      'number',
+                      ['number', 'number', 'number']),
   eddsa_verify: getEmsc('GNUNET_CRYPTO_eddsa_verify',
-    'number',
-    ['number', 'number', 'number', 'number']),
+                        'number',
+                        ['number', 'number', 'number', 'number']),
   hash_create_random: getEmsc('GNUNET_CRYPTO_hash_create_random',
-    'void',
-    ['number', 'number']),
+                              'void',
+                              ['number', 'number']),
   rsa_blinding_key_destroy: getEmsc('GNUNET_CRYPTO_rsa_blinding_key_free',
-    'void',
-    ['number']),
+                                    'void',
+                                    ['number']),
   random_block: getEmsc('GNUNET_CRYPTO_random_block',
-    'void',
-    ['number', 'number', 'number']),
+                        'void',
+                        ['number', 'number', 'number']),
   hash_context_abort: getEmsc('GNUNET_CRYPTO_hash_context_abort',
-    'void',
-    ['number']),
+                              'void',
+                              ['number']),
   hash_context_read: getEmsc('GNUNET_CRYPTO_hash_context_read',
-    'void',
-    ['number', 'number', 'number']),
+                             'void',
+                             ['number', 'number', 'number']),
   hash_context_finish: getEmsc('GNUNET_CRYPTO_hash_context_finish',
-    'void',
-    ['number', 'number']),
+                               'void',
+                               ['number', 'number']),
 };
 
 var emscAlloc = {
   get_amount: getEmsc('TALER_WRALL_get_amount',
-    'number',
-    ['number', 'number', 'number', 'string']),
+                      'number',
+                      ['number', 'number', 'number', 'string']),
   eddsa_key_create: getEmsc('GNUNET_CRYPTO_eddsa_key_create',
-    'number', []),
+                            'number', []),
   ecdsa_key_create: getEmsc('GNUNET_CRYPTO_ecdsa_key_create',
                             'number', []),
   eddsa_public_key_from_private: getEmsc(
@@ -130,41 +130,41 @@ var emscAlloc = {
     'number',
     ['number']),
   data_to_string_alloc: getEmsc('GNUNET_STRINGS_data_to_string_alloc',
-    'number',
-    ['number', 'number']),
+                                'number',
+                                ['number', 'number']),
   purpose_create: getEmsc('TALER_WRALL_purpose_create',
-    'number',
-    ['number', 'number', 'number']),
+                          'number',
+                          ['number', 'number', 'number']),
   rsa_blind: getEmsc('GNUNET_CRYPTO_rsa_blind',
-    'number',
-    ['number', 'number', 'number', 'number']),
+                     'number',
+                     ['number', 'number', 'number', 'number', 'number']),
   rsa_blinding_key_create: getEmsc('GNUNET_CRYPTO_rsa_blinding_key_create',
-    'number',
-    ['number']),
+                                   'number',
+                                   ['number']),
   rsa_blinding_key_encode: getEmsc('GNUNET_CRYPTO_rsa_blinding_key_encode',
-    'number',
-    ['number', 'number']),
+                                   'number',
+                                   ['number', 'number']),
   rsa_signature_encode: getEmsc('GNUNET_CRYPTO_rsa_signature_encode',
-    'number',
-    ['number', 'number']),
+                                'number',
+                                ['number', 'number']),
   rsa_blinding_key_decode: getEmsc('GNUNET_CRYPTO_rsa_blinding_key_decode',
-    'number',
-    ['number', 'number']),
+                                   'number',
+                                   ['number', 'number']),
   rsa_public_key_decode: getEmsc('GNUNET_CRYPTO_rsa_public_key_decode',
-    'number',
-    ['number', 'number']),
+                                 'number',
+                                 ['number', 'number']),
   rsa_signature_decode: getEmsc('GNUNET_CRYPTO_rsa_signature_decode',
-    'number',
-    ['number', 'number']),
+                                'number',
+                                ['number', 'number']),
   rsa_public_key_encode: getEmsc('GNUNET_CRYPTO_rsa_public_key_encode',
-    'number',
-    ['number', 'number']),
+                                 'number',
+                                 ['number', 'number']),
   rsa_unblind: getEmsc('GNUNET_CRYPTO_rsa_unblind',
-    'number',
-    ['number', 'number', 'number']),
+                       'number',
+                       ['number', 'number', 'number']),
   hash_context_start: getEmsc('GNUNET_CRYPTO_hash_context_start',
-    'number',
-    []),
+                              'number',
+                              []),
   malloc: (size: number) => Module._malloc(size),
 };
 
@@ -359,9 +359,9 @@ export class Amount extends MallocArenaObject {
     super(arena);
     if (args) {
       this.nativePtr = emscAlloc.get_amount(args.value,
-        0,
-        args.fraction,
-        args.currency);
+                                            0,
+                                            args.fraction,
+                                            args.currency);
     } else {
       this.nativePtr = emscAlloc.get_amount(0, 0, 0, "");
     }
@@ -514,12 +514,12 @@ abstract class PackedArenaObject extends MallocArenaObject {
     // to the emscripten heap first.
     let buf = ByteArray.fromString(s);
     let res = emsc.string_to_data(buf.nativePtr,
-      s.length,
-      this.nativePtr,
-      this.size());
+                                  s.length,
+                                  this.nativePtr,
+                                  this.size());
     buf.destroy();
     if (res < 1) {
-      throw { error: "wrong encoding" };
+      throw {error: "wrong encoding"};
     }
   }
 
@@ -618,7 +618,6 @@ export class EcdsaPrivateKey extends PackedArenaObject {
 mixinStatic(EcdsaPrivateKey, fromCrock);
 
 
-
 function fromCrock(s: string) {
   let x = new this();
   x.alloc();
@@ -673,7 +672,7 @@ function makeFromCrock(decodeFn: (p: number, s: number) => number) {
     let obj = new this(a);
     let buf = ByteArray.fromCrock(s);
     obj.setNative(decodeFn(buf.getNative(),
-      buf.size()));
+                           buf.size()));
     buf.destroy();
     return obj;
   }
@@ -682,7 +681,7 @@ function makeFromCrock(decodeFn: (p: number, s: number) => number) {
 }
 
 function makeToCrock(encodeFn: (po: number,
-  ps: number) => number): () => string {
+                                ps: number) => number): () => string {
   function toCrock() {
     let ptr = emscAlloc.malloc(PTR_SIZE);
     let size = emscAlloc.rsa_blinding_key_encode(this.nativePtr, ptr);
@@ -780,12 +779,12 @@ export class EccSignaturePurpose extends PackedArenaObject {
   payloadSize: number;
 
   constructor(purpose: SignaturePurpose,
-    payload: PackedArenaObject,
-    a?: Arena) {
+              payload: PackedArenaObject,
+              a?: Arena) {
     super(a);
     this.nativePtr = emscAlloc.purpose_create(purpose,
-      payload.nativePtr,
-      payload.size());
+                                              payload.nativePtr,
+                                              payload.size());
     this.payloadSize = payload.size();
   }
 }
@@ -1121,21 +1120,31 @@ mixin(RsaSignature, makeEncode(emscAlloc.rsa_signature_encode));
 
 
 export function rsaBlind(hashCode: HashCode,
-  blindingKey: RsaBlindingKeySecret,
-  pkey: RsaPublicKey,
-  arena?: Arena): ByteArray {
-  let ptr = emscAlloc.malloc(PTR_SIZE);
-  let s = emscAlloc.rsa_blind(hashCode.nativePtr,
-    blindingKey.nativePtr,
-    pkey.nativePtr,
-    ptr);
-  return new ByteArray(s, Module.getValue(ptr, '*'), arena);
+                         blindingKey: RsaBlindingKeySecret,
+                         pkey: RsaPublicKey,
+                         arena?: Arena): ByteArray|null {
+  let buf_ptr_out = emscAlloc.malloc(PTR_SIZE);
+  let buf_size_out = emscAlloc.malloc(PTR_SIZE);
+  let res = emscAlloc.rsa_blind(hashCode.nativePtr,
+                                blindingKey.nativePtr,
+                                pkey.nativePtr,
+                                buf_ptr_out,
+                                buf_size_out);
+  let buf_ptr = Module.getValue(buf_ptr_out, '*');
+  let buf_size = Module.getValue(buf_size_out, '*');
+  emsc.free(buf_ptr_out);
+  emsc.free(buf_size_out);
+  if (res != GNUNET_OK) {
+    // malicious key
+    return null;
+  }
+  return new ByteArray(buf_size, buf_ptr, arena);
 }
 
 
 export function eddsaSign(purpose: EccSignaturePurpose,
-  priv: EddsaPrivateKey,
-  a?: Arena): EddsaSignature {
+                          priv: EddsaPrivateKey,
+                          a?: Arena): EddsaSignature {
   let sig = new EddsaSignature(a);
   sig.alloc();
   let res = emsc.eddsa_sign(priv.nativePtr, purpose.nativePtr, sig.nativePtr);
@@ -1147,14 +1156,14 @@ export function eddsaSign(purpose: EccSignaturePurpose,
 
 
 export function eddsaVerify(purposeNum: number,
-  verify: EccSignaturePurpose,
-  sig: EddsaSignature,
-  pub: EddsaPublicKey,
-  a?: Arena): boolean {
+                            verify: EccSignaturePurpose,
+                            sig: EddsaSignature,
+                            pub: EddsaPublicKey,
+                            a?: Arena): boolean {
   let r = emsc.eddsa_verify(purposeNum,
-    verify.nativePtr,
-    sig.nativePtr,
-    pub.nativePtr);
+                            verify.nativePtr,
+                            sig.nativePtr,
+                            pub.nativePtr);
   if (r === GNUNET_OK) {
     return true;
   }
@@ -1163,13 +1172,13 @@ export function eddsaVerify(purposeNum: number,
 
 
 export function rsaUnblind(sig: RsaSignature,
-  bk: RsaBlindingKeySecret,
-  pk: RsaPublicKey,
-  a?: Arena): RsaSignature {
+                           bk: RsaBlindingKeySecret,
+                           pk: RsaPublicKey,
+                           a?: Arena): RsaSignature {
   let x = new RsaSignature(a);
   x.nativePtr = emscAlloc.rsa_unblind(sig.nativePtr,
-    bk.nativePtr,
-    pk.nativePtr);
+                                      bk.nativePtr,
+                                      pk.nativePtr);
   return x;
 }
 
@@ -1208,16 +1217,19 @@ export interface FreshCoin {
   blindingKey: RsaBlindingKeySecret;
 }
 
-export function setupFreshCoin(secretSeed: TransferSecretP, coinIndex: number): FreshCoin {
+export function setupFreshCoin(secretSeed: TransferSecretP,
+                               coinIndex: number): FreshCoin {
   let priv = new EddsaPrivateKey();
   priv.isWeak = true;
   let blindingKey = new RsaBlindingKeySecret();
   blindingKey.isWeak = true;
 
-  let buf = kdf(priv.size() + blindingKey.size(), UInt32.fromNumber(coinIndex), ByteArray.fromString("taler-coin-derivation"));
+  let buf = kdf(priv.size() + blindingKey.size(),
+                UInt32.fromNumber(coinIndex),
+                ByteArray.fromString("taler-coin-derivation"));
 
   priv.nativePtr = buf.nativePtr;
   blindingKey.nativePtr = buf.nativePtr + priv.size();
 
-  return { priv, blindingKey };
+  return {priv, blindingKey};
 }
\ No newline at end of file
diff --git a/lib/wallet/wallet.ts b/lib/wallet/wallet.ts
index b248d5315..264eef250 100644
--- a/lib/wallet/wallet.ts
+++ b/lib/wallet/wallet.ts
@@ -797,8 +797,6 @@ export class Wallet {
   }
 
   async storeCoin(coin: Coin): Promise<void> {
-    console.log("storing coin", new Date());
-
     let historyEntry: HistoryRecord = {
       type: "withdraw",
       timestamp: (new Date).getTime(),
diff --git a/lib/wallet/wxMessaging.ts b/lib/wallet/wxMessaging.ts
index 2c69afc99..07f5cc1d8 100644
--- a/lib/wallet/wxMessaging.ts
+++ b/lib/wallet/wxMessaging.ts
@@ -286,7 +286,6 @@ class ChromeNotifier implements Notifier {
   }
 
   notify() {
-    console.log("notifying all ports");
     for (let p of this.ports) {
       p.postMessage({ notify: true });
     }
diff --git a/pages/confirm-create-reserve.tsx b/pages/confirm-create-reserve.tsx
index 3b5a4d161..9bff0e42a 100644
--- a/pages/confirm-create-reserve.tsx
+++ b/pages/confirm-create-reserve.tsx
@@ -172,7 +172,7 @@ class ExchangeSelection extends ImplicitStateComponent<ExchangeSelectionProps> {
 
 
   renderAdvanced(): JSX.Element {
-    if (this.detailCollapsed() && this.url() !== null) {
+    if (this.detailCollapsed() && this.url() !== null && !this.statusString()) {
       return (
         <button className="linky"
                 onClick={() => this.detailCollapsed(false)}>
@@ -224,6 +224,13 @@ class ExchangeSelection extends ImplicitStateComponent<ExchangeSelectionProps> {
         <em>{shortName}</em>
       </p>;
     }
+    if (this.statusString()) {
+      return (
+        <p>
+          <strong style="color: red;">A problem occured, see below.</strong>
+        </p>
+      );
+    }
     return (
       <p>
         Information about fees will be available when an exchange provider is selected.