Implement Merkle hash verification
diff --git a/js/encoding/ASN1/hex.js b/js/encoding/ASN1/hex.js
new file mode 100644
index 0000000..f617183
--- /dev/null
+++ b/js/encoding/ASN1/hex.js
@@ -0,0 +1,55 @@
+// Hex JavaScript decoder

+// Copyright (c) 2008 Lapo Luchini <lapo@lapo.it>

+

+// Permission to use, copy, modify, and/or distribute this software for any

+// purpose with or without fee is hereby granted, provided that the above

+// copyright notice and this permission notice appear in all copies.

+// 

+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

+

+Hex = {};

+

+Hex.decode = function(a) {

+    if (Hex.decoder == undefined) {

+        var hex = "0123456789ABCDEF";

+        var allow = " \f\n\r\t\u00A0\u2028\u2029";

+        var dec = [];

+        for (var i = 0; i < 16; ++i)

+            dec[hex.charAt(i)] = i;

+        hex = hex.toLowerCase();

+        for (var i = 10; i < 16; ++i)

+            dec[hex.charAt(i)] = i;

+        for (var i = 0; i < allow.length; ++i)

+            dec[allow.charAt(i)] = -1;

+        Hex.decoder = dec;

+    }

+    var out = [];

+    var bits = 0, char_count = 0;

+    for (var i = 0; i < a.length; ++i) {

+        var c = a.charAt(i);

+        if (c == '=')

+            break;

+        c = Hex.decoder[c];

+        if (c == -1)

+            continue;

+        if (c == undefined)

+            throw 'Illegal character at offset ' + i;

+        bits |= c;

+        if (++char_count >= 2) {

+            out[out.length] = bits;

+            bits = 0;

+            char_count = 0;

+        } else {

+            bits <<= 4;

+        }

+    }

+    if (char_count)

+        throw "Hex encoding incomplete: 4 bits missing";

+    return out;

+}