DB structure, emscripten interface

10 files changed, 967 insertions, 37 deletions

diff --git a/extension/background/db.js b/extension/background/db.js
new file mode 100644
index 000000000..9be933d9c
--- /dev/null
+++ b/extension/background/db.js
@@ -0,0 +1,220 @@
+"use strict";
+
+var DB = function () {
+  let DB = {}; // returned object with exported functions
+
+  let DB_NAME = "taler";
+  let DB_VERSION = 1;
+
+  let db = null;
+  let is_ready = null;
+
+  DB.open = function (onsuccess, onerror)
+  {
+    is_ready = false;
+
+    let req = indexedDB.open(DB_NAME, DB_VERSION);
+    req.onerror = onerror;
+    req.onsuccess = function (event)
+    {
+      db = event.target.result;
+      is_ready = true;
+      if (onsuccess)
+        onsuccess();
+    };
+
+    req.onupgradeneeded = function (event)
+    {
+      console.log ("DB: upgrade needed: oldVersion = "+ event.oldVersion);
+
+      db = event.target.result;
+      db.onerror = onerror;
+
+      switch (event.oldVersion)
+      {
+        case 0: // DB does not exist yet
+        {
+          let example = {};
+
+          let mints = db.createObjectStore("mints", { keyPath: "mint_pub" });
+          mints.createIndex("name", "name", { unique: true });
+
+          example.mint = {
+            mint_pub: "<mint's master pub key>",	// length: 32
+            name: "Mint One",
+            url: "https://mint.one/",
+          };
+
+          let denoms = db.createObjectStore("denoms", { keyPath: "denom_pub" });
+
+          example.denom = {
+            denom_pub: "<denom pub key>",		// length: 32
+            mint_pub: "<mint's master pub key>",	// length: 32
+            mint_sig: "<mint's sig>",		// length: 64
+            withdraw_expiry_time: 1234567890,
+            deposit_expiry_time: 1234567890,
+            start_time: 1234567890,
+            value: {
+              value: 1,
+              fraction: 230000, // 0..999999
+              currency: "EUR",
+            },
+            fee: {
+              withdraw: {
+                value: 0,
+                fraction: 100000,
+                currency: "EUR",
+              },
+              deposit: {
+                value: 0,
+                fraction: 100000,
+                currency: "EUR",
+              },
+              refresh: {
+                value: 0,
+                fraction: 100000,
+                currency: "EUR",
+              },
+            },
+          };
+
+          let reserves = db.createObjectStore("reserves", { keyPath: "reserve_pub"});
+          example.reserve = {
+            reserve_pub: "<pub key>",
+            reserve_priv: "<priv key>",
+            mint_pub: "<mint's master pub key>",
+            initial: {
+              value: 1,
+              fraction: 230000,
+              currency: "EUR",
+            },
+            current: {
+              value: 1,
+              fraction: 230000,
+              currency: "EUR",
+              blind_session_pub: "<pub key>",
+              status_sig: "<sig>",
+            },
+          };
+
+          let withdrawals = db.createObjectStore("withdrawals", { keyPath: "id", autoIncrement: true });
+          example.withdrawal = {
+            id: 1, // generated
+            reserve_pub: "<pub key>",
+            reserve_sig: "<sig>",
+            denom_pub: "<pub key",
+            blind_session_pub: "<pub key>",
+            blind_priv: "<priv key>",
+            coin_pub: "<pub key>",
+            coin_priv: "<priv key>",
+            coin_ev: "",
+          };
+
+          let coins = db.createObjectStore("coins", { keyPath: "coin_pub" });
+          example.coin = {
+            // coin either has a withdraw_id or refresh_id
+            // or it is imported in which case both are null
+            withdraw_id: 1,		// can be null
+            refresh_id: null,	// can be null
+            is_refreshed: false,
+            denom_pub: "<pub key>",
+            coin_pub: "<pub key>",
+            coin_priv: "<priv key>",
+            denom_sig: "<sig>",
+            spent: {
+              value: 1,
+              fraction: 230000,
+            },
+            transactions: [ 123, 456 ],	// list of transaction IDs where this coin was used
+          };
+
+          let transactions = db.createObjectStore("transactions", { keyPath: "id", autoIncrement: true });
+          example.transaction = {
+            id: 1, // generated
+            wire_hash: "<hash>",
+            value: {
+              value: 1,
+              fraction: 230000,
+              currency: "EUR",
+            },
+            contract: "<JSON>",
+            is_checkout_done: true,
+            is_confirmed: true,
+            fulfillment_url: "https://some.shop/transaction/completed",
+          };
+
+          let refresh = db.createObjectStore("refresh");
+          example.refresh = {
+            // TODO
+          };
+        }
+      }
+
+      is_ready = true;
+      if (onsuccess)
+        onsuccess();
+    }
+  };
+
+
+  DB.close = function ()
+  {
+    db.close();
+  };
+
+
+  DB.wallet_get = function (onresult, onerror)
+  {
+    let wallet = { };
+
+    let tr = db.transaction([ "coins", "denoms" ], "readonly");
+    let coins = tr.objectStore("coins");
+    let denoms = tr.objectStore("denoms");
+
+    let coins_cur = coins.openCursor();
+    coins_cur.onerror = onerror;
+    coins_cur.onsuccess = function ()
+    {
+      let cur = event.target.result;
+      if (cur) {
+        let denom_get = denoms.get(cur.valcue.denom_pub);
+        denom_get.onerror = onerror;
+        denom_get.onsuccess = function (event)
+        {
+          let denom = event.target.result;
+          if (denom.currency in wallet)
+          {
+            let w = wallet[denom.currency];
+            w.value += denom.value;
+            w.fraction = (w.fraction + denom.fraction) % 1000000;
+            if (1000000 <= w.fraction + denom.fraction)
+              w.value++;
+          }
+          else
+          {
+            wallet[denom.currency] = denom;
+          }
+          cur.continue();
+        }
+      }
+      else // no more entries
+      {
+        onresult(wallet);
+      }
+    };
+  };
+
+
+  DB.transaction_list = function (onresult, onerror)
+  {
+    // TODO
+  };
+
+
+  DB.reserve_list = function (onresult, onerror)
+  {
+    // TODO
+  };
+
+  return DB;
+}();
diff --git a/extension/background/emscriptif.js b/extension/background/emscriptif.js
new file mode 100644
index 000000000..62b233eda
--- /dev/null
+++ b/extension/background/emscriptif.js
@@ -0,0 +1,587 @@
+/*
+
+  This file is part of TALER
+  Copyright (C) 2014, 2015 Christian Grothoff (and other contributing authors)
+
+  TALER is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  TALER is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
+
+
+*/
+
+
+var EXPORTED_SYMBOLS = [
+  'TWRhelloWorld',
+  'TWRgetValue',
+  'TWRgetFraction',
+  'TWRgetCurrency',
+  'TamountCmp',
+  'TWRverifyConfirmation',
+  'TWRverifySignKey',
+  'TWRverifyDenom',
+  'TWRverifyDenoms',
+  'TWRALLrsaPublicKeyHash',
+  'TWRALLgetEncodingFromRsaSignature',
+  'DWRtestStringCmp',
+  'TWRmultiplyAmount',
+  'TWRmultiplyAmounts',
+  'DWRdumpAmount',
+  'TWRALLgetAmount',
+  'DWRtestString',
+  'DWRgetPurpose',
+  'TWReddsaVerify',
+  'TamountAdd',
+  'TamountSubtract',
+  'TWRALLmakeEddsaSignature',
+  'TWRALLamountAdd',
+  'TWRALLeddsaPublicKeyFromPrivate',
+  'TWRALLeddsaPublicKeyFromPrivString',
+  'TWRALLeddsaPrivateKeyFromString',
+  'TWRALLeccEcdh',
+  'TWRALLhash',
+  'TWRALLecdhePublicKeyFromPrivateKey',
+  'TWRALLrsaPublicKeyDecodeFromString',
+  'GCeddsaSign',
+  'TWRALLmakeWithdrawBundle',
+  'GCALLrsaSignatureDecode',
+  'GCrsaSignatureEncode',
+  'TWRALLsignDepositPermission',
+  'GCALLrsaPublicKeyDecode',
+  'GCALLrsaPublicKeyEncode',
+  'WRALLeddsaPublicKey',
+  'GCALLeddsaKeyCreate',
+  'WRALLecdhePublicKey ',
+  'GSALLdataToStringAlloc',
+  'TWRgnunetFree',
+  'GSstringToData',
+  'TWRALLgetCurrentTime',
+  'TWRgetFancyTime',
+  'GChash',
+  'getHashedArray',
+  'TWRALLsignTest',
+  'GCALLecdheKeyCreate',
+  'GCecdheKeyGetPublic',
+  'WRALLecdhePublicKey',
+  'WRverifyTest',
+  'GCeccEcdh',
+  'TWRALLgenSymmetricKey',
+  'TWRALLgenInitVector',
+  'GCsymmetricDecrypt',
+  'GCsymmetricEncrypt',
+  'TWRALLgenKeyFromBlob',
+  'GCALLrsaPrivateKeyGetPublic',
+  'GCALLrsaPrivateKeyCreate',
+  'GCALLrsaBlindingKeyCreate',
+  'GCrsaBlindingKeyFree',
+  'GCrsaPublicKeyFree',
+  'GCrsaPrivateKeyFree',
+  'GCALLrsaBlind',
+  'GCALLrsaUnblind',
+  'GCALLrsaSign',
+  'GCrsaVerify',
+  'GCrsaSignatureFree',
+  'GCeddsaKeyGetPublic',
+  'WRALLmakePurpose',
+  'GChkdf',
+  'emscMalloc',
+  'emscFree'
+];
+
+/* The following definition is needed to make emscripted library to remain
+  'alive' after its loading. Otherwise, the normal behaviour would be:
+  loading -> look for a 'main()' -> if one is found execute it then exit,
+  otherwise just exit. See https://kripken.github.io/emscripten-site/docs/getting_started/FAQ.html
+  DO NOTE: this definition MUST precede the importing/loading of the emscripted
+  library */
+
+/* FIXME
+getLastWindow().Module = {
+
+  onRuntimeInitialized: function() {
+
+  }
+
+};
+*/
+
+/* According to emscripten's design, we need our emscripted library to be executed
+  with a 'window' object as its global scope.
+  Note: that holds on emscripten's functions too, that is they need to be *explicitly*
+  run with some 'window' object as their global scope. In practice, given a function
+  'foo' pointing to some emscripted function, that is accomplished by the mean of 'call()'
+  or 'apply()' methods; so, being 'someWin' a 'window' object, the statements
+
+  foo.call('someWin', arg1, .., argN) or foo.apply('someWin', ['arg1', .., 'argN']) will
+  execute foo(arg1, .., argN) with 'someWin' as its global scope.
+  See http://www.bennadel.com/blog/2265-changing-the-execution-context-of-javascript
+  -functions-using-call-and-apply.htm. */
+
+/* The naming convention is such that:
+  - 'GCfunctionName' takes its code from GNUNET_CRYPTO_function_name
+  - 'GCALLfunctionName' takes its code from GNUNET_CRYPTO_function_name and returns
+     a pointer that must be deallocated using 'WRgnunetFree' (that takes its code from
+     'GNUNET_free' in the wrapper)
+  - 'GSfunctionName' and 'GSALLfunctionName' comply to the same convention respect to
+    GNUNET_STRINGS_* realm.
+  - 'TWRfunctionName' takes its code from 'TALER_function_name' in the wrapper.
+  - 'TWRALLfunctionName' takes its code from 'TALER_ALL_function_name' in the wrapper
+    and returns a pointer that must be deallocated using 'TWRgnunetFree' (or a function
+    provided by some emscripted routine) (the 'wrapper' is an additional layer written in
+    C that does some struct(s) manipulations where that is uncovenient to do from JavaScript.
+    Currently located at '../../emscripten/testcases/wrap.c')
+  - The same applies to 'TfunctionName' and 'TALLfunctionName', to indicate that the
+    respective functions come from (the emscripted version of) TALER_* realm. */
+
+
+// shortcut to emscr's 'malloc'
+function emscMalloc(size) {
+
+  var ptr = Module._malloc(size);
+  return ptr;
+
+}
+
+/* shortcut to emscr's 'free'. This function is problematic:
+  it randomly stops working giving 'emscFree is not a function'
+  error */
+function emscFree(ptr) {
+
+  Module._free(ptr);
+
+}
+
+var getEmsc = Module.cwrap;
+
+var TWRhelloWorld = getEmsc('TALER_WR_hello_world', 'void', []);
+
+var TWRverifyConfirmation = getEmsc('TALER_WR_verify_confirmation',
+                                    'number',
+                                   ['number',
+                                    'number',
+     		                    'number',
+                                    'number',
+				    'number',
+				    'number',
+                                    'number',
+                                    'number',
+                                    'number',
+                                    'number',
+                                    'number']);
+var TWRgetValue = getEmsc('TALER_WR_get_value',
+                          'number',
+			 ['number']);
+
+var TWRgetFraction = getEmsc('TALER_WR_get_fraction',
+                             'number',
+			    ['number']);
+
+var TWRgetCurrency = getEmsc('TALER_WR_get_currency',
+                             'string',
+			    ['number']);
+
+
+var TWRmultiplyAmounts = getEmsc('TALER_WR_multiply_amounts',
+                                 'number',
+			        ['number',
+			         'number'] );
+
+var TWRmultiplyAmount = getEmsc('TALER_WR_multiply_amount',
+                               'number',
+			      ['number',
+			       'number'] );
+
+var TWRALLrsaPublicKeyHash = getEmsc('TALER_WRALL_rsa_public_key_hash',
+                                     'number',
+				    ['number']);
+
+var TWRverifyDenom = getEmsc('TALER_WR_verify_denom',
+                             'number',
+                            ['number',
+                             'number',
+		             'number',
+                             'number',
+                             'number',
+                             'number',
+                             'number',
+                             'number',
+                             'number',
+			     'number',
+			     'number']);
+
+var TWRverifyDenoms = getEmsc('TALER_WR_verify_denoms',
+                              'number',
+			     ['number',
+			      'number',
+                              'number',
+			      'number',
+                              'number']);
+
+var TWRverifySignKey = getEmsc('TALER_WR_verify_sign_key',
+                               'number',
+                              ['number',
+			       'number',
+			       'number',
+                               'number',
+			       'number',
+			       'number']);
+
+
+var TWRALLgetEncodingFromRsaSignature = getEmsc('TALER_WRALL_get_encoding_from_rsa_signature',
+                                                'number',
+                                               ['number']);
+
+var TamountCmp = getEmsc('TALER_amount_cmp',
+                         'number',
+			['number',
+			 'number']);
+
+var DWRdumpAmount = getEmsc('DEBUG_WR_dump_amount',
+                            'void'
+			   ['number']);
+
+var DWRtestStringCmp = getEmsc('DEBUG_WR_test_string_cmp',
+                               'number',
+			      ['number',
+			       'string']);
+
+var TWRALLgetAmount = getEmsc('TALER_WRALL_get_amount',
+                              'number',
+			     ['number',
+			      'number',
+			      'number',
+			      'string']);
+
+var DWRgetPurpose = getEmsc('DEBUG_WR_get_purpose',
+                            'number',
+			   ['number']);
+
+var TWReddsaVerify = getEmsc('TALER_WR_eddsa_verify',
+                             'number',
+			    ['string',
+			     'number',
+			     'number',
+			     'number']);
+
+var TWRALLmakeEddsaSignature = getEmsc('TALER_WRALL_make_eddsa_signature',
+                                       'number',
+				      ['number',
+				       'number']);
+
+var TWRALLamountAdd = getEmsc('TALER_WRALL_amount_add',
+                              'number',
+			     ['number',
+			      'number',
+			      'number',
+			      'number',
+                              'number',
+			      'number',
+			      'string']);
+
+var TamountSubtract = getEmsc('TALER_amount_subtract',
+                              'number',
+			     ['number',
+			      'number',
+			      'number']);
+
+var TamountAdd = getEmsc('TALER_amount_add',
+                         'number',
+			['number',
+			 'number',
+			 'number']);
+var TWRALLeddsaPublicKeyFromPrivate = getEmsc('TALER_WRALL_eddsa_public_key_from_private',
+                                              'number',
+                                             ['number']);
+
+var TWRALLeddsaPublicKeyFromPrivString = getEmsc('TALER_WRALL_eddsa_public_key_from_priv_string',
+                                                 'number',
+                                                ['string']);
+
+var TWRALLsignDepositPermission = getEmsc('TALER_WRALL_sign_deposit_permission',
+                                          'number',
+					 ['number',
+					  'number',
+                                          'number',
+					  'number',
+					  'number',
+					  'number',
+					  'number',
+					  'number',
+					  'number',
+					  'number']);
+
+var TWRALLeddsaPrivateKeyFromString = getEmsc('TALER_WRALL_eddsa_private_key_from_string',
+                                              'number',
+					     ['string']);
+
+var TWRALLrsaPublicKeyDecodeFromString = getEmsc('TALER_WRALL_rsa_public_key_decode_from_string',
+                                                 'number',
+						['string']);
+
+var TWRALLecdhePublicKeyFromPrivateKey = getEmsc('TALER_WRALL_ecdhe_public_key_from_private_key',
+                                                 'number',
+						['number']);
+
+var TWRALLeccEcdh = getEmsc('TALER_WRALL_ecc_ecdh',
+                            'number',
+			   ['number',
+			    'number',
+			    'number']);
+
+var TWRALLmakeWithdrawBundle = getEmsc('TALER_WRALL_make_withdraw_bundle',
+                                       'number',
+				      ['number',
+				       'number',
+				       'number',
+				       'number',
+				       'number',
+				       'number']);
+
+var WRALLmakePurpose = getEmsc('WRALL_make_purpose',
+                               'number',
+			      ['string',
+			       'number',
+			       'number',
+			       'number']);
+
+var GCALLrsaSignatureDecode = getEmsc('GNUNET_CRYPTO_rsa_signature_decode',
+                                      'number',
+				     ['number',
+				      'number']);
+
+var GCALLrsaSignatureEncode = getEmsc('GNUNET_CRYPTO_rsa_signature_encode',
+                                      'number',
+				     ['number',
+				     'number']);
+
+var GCALLrsaPublicKeyEncode = getEmsc('GNUNET_CRYPTO_rsa_public_key_encode',
+                                      'number',
+				     ['number',
+				      'number']);
+
+var GCALLrsaPublicKeyDecode = getEmsc('GNUNET_CRYPTO_rsa_public_key_decode',
+                                      'number',
+				     ['number',
+				      'number']);
+
+var GCALLrsaPrivateKeyGetPublic = getEmsc('GNUNET_CRYPTO_rsa_private_key_get_public',
+                                          'number',
+					 ['number']);
+
+var GCALLrsaPrivateKeyCreate = getEmsc('GNUNET_CRYPTO_rsa_private_key_create',
+                                       'number',
+				      ['number']);
+
+var GCALLrsaBlindingKeyCreate = getEmsc('GNUNET_CRYPTO_rsa_blinding_key_create',
+                                        'number',
+				       ['number']);
+
+var GCrsaBlindingKeyFree = getEmsc('GNUNET_CRYPTO_rsa_blinding_key_free',
+                                   'void',
+				  ['number']);
+
+var GCrsaPublicKeyFree = getEmsc('GNUNET_CRYPTO_rsa_public_key_free',
+                                 'void',
+				['number']);
+
+var GCrsaPrivateKeyFree = getEmsc('GNUNET_CRYPTO_rsa_private_key_free',
+                                  'void',
+				 ['number']);
+
+var GCALLrsaBlind = getEmsc('GNUNET_CRYPTO_rsa_blind',
+                            'number',
+			   ['number',
+			    'number',
+			    'number',
+			    'number']);
+
+var GCALLrsaUnblind = getEmsc('GNUNET_CRYPTO_rsa_unblind',
+                              'number',
+			     ['number',
+			      'number',
+			      'number']);
+
+var GCALLrsaSign = getEmsc('GNUNET_CRYPTO_rsa_sign',
+                           'number',
+			  ['number',
+			   'number',
+			   'number']);
+
+var GCrsaVerify = getEmsc('GNUNET_CRYPTO_rsa_verify',
+                          'number',
+			 ['number',
+			  'number',
+			  'number']);
+
+var GCrsaSignatureFree = getEmsc('GNUNET_CRYPTO_rsa_signature_free',
+                                 'void',
+				['number']);
+
+var GChkdf = getEmsc('GNUNET_CRYPTO_hkdf',
+                     'number',
+		    ['number',
+		     'number',
+		     'number',
+		     'number',
+		     'number',
+		     'number',
+		     'number',
+		     'number']);
+
+var TWRALLgenKeyFromBlob = getEmsc('TALER_WRALL_gen_key_from_blob',
+                                   'number',
+				  ['string',
+				   'number',
+				   'number']);
+
+var DWRtestString = getEmsc('DEBUG_WR_test_string',
+                            'void',
+			   ['number',
+			    'number',
+			    'string']);
+
+var GCsymmetricDecrypt = getEmsc('GNUNET_CRYPTO_symmetric_decrypt',
+                                 'number',
+				['number',
+				 'number',
+				 'number',
+				 'number',
+				 'number']);
+
+var GCsymmetricEncrypt = getEmsc('GNUNET_CRYPTO_symmetric_encrypt',
+                                 'number',
+				['number',
+				 'number',
+				 'number',
+				 'number',
+				 'number']);
+
+/* returns a pointer to a symmetric session key strucure and takes a salt, a
+  (pointer to) binary data used to generate the key, and the length of that
+  data */
+var TWRALLgenSymmetricKey = getEmsc('TALER_WRALL_gen_symmetric_key',
+                                    'number',
+				   ['string',
+				    'number',
+				    'number']);
+
+/* returns a pointer to a init. vector strucure and takes a salt, a
+  (pointer to) binary data used to generate the key, and the length of that
+  data */
+var TWRALLgenInitVector = getEmsc('TALER_WRALL_gen_init_vector',
+                                  'number',
+				 ['string',
+				  'number',
+				  'number']);
+
+// return key material from ECC keys
+var GCeccEcdh = getEmsc('GNUNET_CRYPTO_ecc_ecdh',
+                        'number',
+		       ['number',
+		        'number',
+			'number']);
+
+// return a pointer to a freshly allocated EddsaPublicKey structure
+/* var WRALLeddsaPublicKey = getEmsc('WRALL_eddsa_public_key',
+                                     'number'); */
+
+// return a pointer to a freshly allocated EcdhePublicKey structure
+/* var WRALLecdhePublicKey = getEmsc('WRALL_ecdhe_public_key',
+                                     'number'); */
+
+/* generates a new eddsa private key, returning a pointer to EddsaPrivateKey
+  structure */
+var GCALLeddsaKeyCreate = getEmsc('GNUNET_CRYPTO_eddsa_key_create',
+                                  'number');
+
+/* extract eddsa public key from a pointer to a EddsaPrivateKey structure
+  and put it in second argument */
+var GCeddsaKeyGetPublic = getEmsc('GNUNET_CRYPTO_eddsa_key_get_public',
+                                  'void',
+				 ['number',
+				  'number']);
+
+/* generates a new ecdhe private key, returning a pointer to EcdhePrivateKey
+  structure */
+var GCALLecdheKeyCreate = getEmsc('GNUNET_CRYPTO_ecdhe_key_create',
+                                  'number');
+
+/* extract eddsa public key from a pointer to a EddsaPrivateKey structure and
+  put it in second argument */
+var GCecdheKeyGetPublic = getEmsc('GNUNET_CRYPTO_ecdhe_key_get_public',
+                                  'void',
+				 ['number',
+				  'number']);
+
+// what to sign, the reason to sign, the location to store the signature
+var GCeddsaSign = getEmsc('GNUNET_CRYPTO_eddsa_sign',
+                          'int',
+			 ['number',
+			  'number',
+			  'number']);
+
+/* get reference to the emscripted primitive: the first parameter is a
+  pointer (note that it points to the emscripten's heap) to the data being
+  encoded, the second is its length */
+var GSALLdataToStringAlloc = getEmsc('GNUNET_STRINGS_data_to_string_alloc',
+                                     'number',
+				    ['number',
+				     'number']);
+
+// import GNUnet's memory deallocator
+var TWRgnunetFree = getEmsc('TALER_WR_GNUNET_free',
+                            'void',
+			   ['number']);
+
+// GNUnet's base32 decoder
+var GSstringToData = getEmsc('GNUNET_STRINGS_string_to_data',
+                             'number',
+			    ['number',
+			     'number',
+			     'number',
+			     'number']);
+
+// get absolute time. Returned value has to be freed by gnunetFree
+var TWRALLgetCurrentTime = getEmsc('TALER_WRALL_get_current_time',
+                                   'number');
+
+// prettyfy time
+var TWRgetFancyTime = getEmsc('TALER_WR_get_fancy_time',
+                              'string',
+			     ['number']);
+
+var TWRALLhash = getEmsc('TALER_WRALL_hash',
+                         'number',
+			['number',
+			 'number']);
+
+/* computes the hashcode of the value pointed to by 'val' and sets the
+  pointer to the location holding the hashcode (which has to be previously
+  allocated and is a reflection of GNUNET_HashCode type). The returned
+  pointer has to be freed by gnunetFree.
+  Its interface is hash('val', 'valSize', 'hashedBuf') */
+var GChash = getEmsc('GNUNET_CRYPTO_hash',
+                     'void',
+		    ['number',
+		     'number',
+		     'number']);
+
+/* this test just takes the private key to sign a dummy hardcoded
+  message. Return a pointer to the signed message (to be freed) */
+var TWRALLsignTest = getEmsc('TALER_WRALL_sign_test',
+                             'number',
+			    ['number']);
+
+/* this test just takes the public key and the signed dummy
+  message. Return GNUNET_OK (=1) if it succeeds, otherwise
+  GNUNET_SYSERR (=-1) */
+var WRverifyTest = getEmsc('WR_verify_test',
+                           'number',
+			  ['number']);
diff --git a/extension/background/libwrapper.js b/extension/background/libwrapper.js
new file mode 120000
index 000000000..8a9ac8e9a
--- /dev/null
+++ b/extension/background/libwrapper.js
@@ -0,0 +1 @@
+../../../wallet_button/firefox_src/content/lib/libWrapper.jsm
\ No newline at end of file
diff --git a/extension/background/wallet.js b/extension/background/wallet.js
index ec7b3fb40..c6fbb5780 100644
--- a/extension/background/wallet.js
+++ b/extension/background/wallet.js
@@ -1,8 +1,40 @@
-// Nothing here yet.
-// Eventually, the backend for the wallet will be implemented here.
-
 'use strict';
 
 //chrome.browserAction.setBadgeBackgroundColor({color: "#000"})
 chrome.browserAction.setBadgeText({text: "42"})
 chrome.browserAction.setTitle({title: "Taler: 42 EUR"})
+
+function test_emscripten ()
+{
+  var cur_time = TWRALLgetCurrentTime();
+  var fancy_time = TWRgetFancyTime(cur_time);
+  console.log('current time: '+ fancy_time);
+}
+
+test_emscripten();
+
+DB.open(function () {
+  console.log ("DB: ready");
+});
+
+chrome.runtime.onMessage.addListener(
+  function (req, sender, onresponse) {
+    console.log("Message: " + req.type +
+                (sender.tab
+                 ? " from a content script: "+ sender.tab.url
+                 : " from the extension"));
+    switch (req.type)
+    {
+      case "WALLET_GET":
+        DB.wallet_get (onresponse);
+        break;
+
+      case "TRANSACTION_LIST":
+        DB.transaction_list (onresponse);
+        break;
+
+      case "RESERVE_LIST":
+        DB.reserve_list (onresponse);
+        break;
+    }
+  });
diff --git a/extension/lib/util.js b/extension/lib/util.js
new file mode 100644
index 000000000..9d83f7e74
--- /dev/null
+++ b/extension/lib/util.js
@@ -0,0 +1,91 @@
+'use strict';
+
+/**
+ * Format amount as String.
+ *
+ * @param amount
+ *        Amount to be formatted.
+ *
+ * @return String, e.g. "1.23"
+ */
+function amount_format (amount)
+{
+  let separator = "." // FIXME: depends on locale
+  return amount.value + separator + amount.fraction.toString().replace(/0+$/, "");
+}
+
+
+/**
+ * Format amount with currency as String.
+ *
+ * @param amount
+ *        Amount to be formatted.
+ *
+ * @return String, e.g. "1.23 EUR"
+ */
+function amount_format_currency (amount)
+{
+  return amount_format(amount) + " " + amount.currency;
+}
+
+
+/**
+ * Convert Date to String.
+ *
+ * Format: YYYY-MM-DD HH:mm
+ *
+ * @param date
+ *        Date to be converted.
+ *
+ * @return String
+ */
+function date_format (date)
+{
+  function pad (number) {
+    if (number < 10) {
+      return '0' + number;
+    }
+    return number;
+  }
+
+  return date.getUTCFullYear() +
+    '-' + pad(date.getUTCMonth() + 1) +
+    '-' + pad(date.getUTCDate()) +
+    ' ' + pad(date.getUTCHours()) +
+    ':' + pad(date.getUTCMinutes());
+  //':' + pad(date.getUTCSeconds());
+}
+
+
+/**
+ * Send HTTP request.
+ *
+ * @param method
+ *        HTTP method.
+ * @param url
+ *        URL to send to.
+ * @param content
+ *        Content of request.
+ * @param content_type
+ *        Content-Type HTTP header.
+ * @param onsuccess
+ *        Function called by XMLHttpRequest on success.
+ * @param onerror
+ *        Function called by XMLHttpRequest on error.
+ *
+ */
+function http_req (method, url, content, content_type, onsuccess, onerror) {
+  var req = new XMLHttpRequest();
+
+  req.onload = function(mintEvt) {
+    if (req.readyState == 4)
+      onsuccess(req.status, req.responseText);
+  };
+
+  req.onerror = onerror;
+  req.open(method, url, true);
+  req.setRequestHeader('Content-Type', content_type);
+  req.send(content);
+
+  return req;
+}
diff --git a/extension/manifest.json b/extension/manifest.json
index 1d0ad6d55..b253c2484 100644
--- a/extension/manifest.json
+++ b/extension/manifest.json
@@ -21,11 +21,6 @@
     "default_popup": "popup/wallet.html"
   },
 
-  "web_accessible_resources": [
-    "popup/reserves.html",
-    "popup/wallet.html"
-  ],
-
   "content_scripts": [
     {
       "matches": ["*://*/*"],
@@ -35,7 +30,14 @@
   ],
 
   "background": {
-    "scripts": ["background/wallet.js"]
-  }
+    "scripts": [
+      "lib/util.js",
+      "background/libwrapper.js",
+      "background/emscriptif.js",
+      "background/db.js",
+      "background/wallet.js"
+    ]
+  },
 
+  "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'"
 }
diff --git a/extension/popup/transactions.html b/extension/popup/transactions.html
index 2dc3fbea0..f51f64cf0 100644
--- a/extension/popup/transactions.html
+++ b/extension/popup/transactions.html
@@ -4,6 +4,7 @@
   <head>
     <meta charset="utf-8">
     <link rel="stylesheet" href="popup.css" type="text/css">
+    <script src="../lib/util.js" type="text/javascript"></script>
     <script src="transactions.js" type="text/javascript"></script>
   </head>
 
diff --git a/extension/popup/transactions.js b/extension/popup/transactions.js
index 7d38d3b36..fbd578114 100644
--- a/extension/popup/transactions.js
+++ b/extension/popup/transactions.js
@@ -1,22 +1,5 @@
 'use strict';
 
-function format_date (date)
-{
-  function pad (number) {
-    if (number < 10) {
-      return '0' + number;
-    }
-    return number;
-  }
-
-  return date.getUTCFullYear() +
-    '-' + pad(date.getUTCMonth() + 1) +
-    '-' + pad(date.getUTCDate()) +
-    ' ' + pad(date.getUTCHours()) +
-    ':' + pad(date.getUTCMinutes());
-  //':' + pad(date.getUTCSeconds());
-}
-
 function add_transaction (date, currency, amount, status, contract)
 {
   let table = document.getElementById('transactions-table');
@@ -26,7 +9,7 @@ function add_transaction (date, currency, amount, status, contract)
 
   let td_date = document.createElement('td');
   td_date.className = 'date';
-  let text_date = document.createTextNode(format_date (date));
+  let text_date = document.createTextNode(date_format (date));
   tr.appendChild(td_date).appendChild(text_date);
 
   let td_amount = document.createElement('td');
diff --git a/extension/popup/wallet.html b/extension/popup/wallet.html
index a6864896b..42d72e676 100644
--- a/extension/popup/wallet.html
+++ b/extension/popup/wallet.html
@@ -4,6 +4,7 @@
   <head>
     <meta charset="utf-8">
     <link rel="stylesheet" href="popup.css" type="text/css">
+    <script src="../lib/util.js" type="text/javascript"></script>
     <script src="wallet.js" type="text/javascript"></script>
   </head>
 
diff --git a/extension/popup/wallet.js b/extension/popup/wallet.js
index cb7399dac..c148abc85 100644
--- a/extension/popup/wallet.js
+++ b/extension/popup/wallet.js
@@ -28,8 +28,13 @@ function select_currency (checkbox, currency, amount)
 
 function add_currency (currency, amount)
 {
+  let empty = document.getElementById('wallet-empty');
+  if (! /\bhidden\b/.test(empty.className))
+    empty.className += ' hidden';
+
   let table = document.getElementById('wallet-table');
   table.className = table.className.replace(/\bhidden\b/, '');
+
   let tr = document.createElement('tr');
   tr.id = 'wallet-table-'+ currency;
   table.appendChild(tr);
@@ -73,13 +78,20 @@ function update_currency (currency, amount)
   checkbox._amount = amount;
 }
 
-document.addEventListener('DOMContentLoaded', function () {
-  let empty = document.getElementById('wallet-empty');
+document.addEventListener(
+  'DOMContentLoaded',
+  function () {
+    chrome.runtime.sendMessage({type: "WALLET_GET"}, function(wallet) {
+      for (let currency in wallet)
+      {
+        let amount = amount_format(wallet[currency]);
+        add_currency(currency, amount);
+      }
+    });
 
-  // FIXME
-  empty.className += ' hidden';
-  add_currency('EUR', 42);
-  add_currency('USD', 17);
-  add_currency('KUD', 1337);
-  update_currency('USD', 23);
-});
+    // FIXME: remove
+    add_currency('EUR', 42);
+    add_currency('USD', 17);
+    add_currency('KUD', 1337);
+    update_currency('USD', 23);
+  });