diff --git a/src/js/base.js b/src/js/base.js
index 47ef551e..be2cab48 100644
--- a/src/js/base.js
+++ b/src/js/base.js
@@ -130,7 +130,11 @@ Base.decode_check = function (version, input, alphabet) {
     if (computed[i] !== checksum[i])
       return NaN;
 
-  return new BigInteger(buffer.slice(1, -4));
+  // We'll use the version byte to add a leading zero, this ensures JSBN doesn't
+  // intrepret the value as a negative number
+  buffer[0] = 0;
+
+  return new BigInteger(buffer.slice(0, -4), 256);
 }
 
 exports.Base = Base;
diff --git a/test/base58-test.js b/test/base58-test.js
new file mode 100644
index 00000000..c143de7b
--- /dev/null
+++ b/test/base58-test.js
@@ -0,0 +1,20 @@
+var buster      = require("buster");
+
+var Seed        = require("../src/js/seed").Seed;
+
+var config      = require('../src/js/config').load(require('./config'));
+
+buster.testCase("Base58", {
+  "Seed" : {
+    "saESc82Vun7Ta5EJRzGJbrXb5HNYk" : function () {
+      var seed = Seed.from_json("saESc82Vun7Ta5EJRzGJbrXb5HNYk");
+      buster.assert.equals(seed.to_hex(), "FF1CF838D02B2CF7B45BAC27F5F24F4F");
+    },
+    "sp6iDHnmiPN7tQFHm5sCW59ax3hfE" : function () {
+      var seed = Seed.from_json("sp6iDHnmiPN7tQFHm5sCW59ax3hfE");
+      buster.assert.equals(seed.to_hex(), "00AD8DA764C3C8AF5F9B8D51C94B9E49");
+    }
+  }
+});
+
+// vim:sw=2:sts=2:ts=8:et
diff --git a/test/sign-test.js b/test/sign-test.js
new file mode 100644
index 00000000..405c8ba5
--- /dev/null
+++ b/test/sign-test.js
@@ -0,0 +1,24 @@
+var buster      = require("buster");
+
+var Seed        = require("../src/js/seed").Seed;
+
+var config      = require('../src/js/config').load(require('./config'));
+
+buster.testCase("Signing", {
+  "Keys" : {
+    "SigningPubKey 1 (ripple-client issue #245)" : function () {
+      var seed = Seed.from_json("saESc82Vun7Ta5EJRzGJbrXb5HNYk");
+      var key = seed.get_key("rBZ4j6MsoctipM6GEyHSjQKzXG3yambDnZ");
+      var pub = key.to_hex_pub();
+      buster.assert.equals(pub, "0396941B22791A448E5877A44CE98434DB217D6FB97D63F0DAD23BE49ED45173C9");
+    },
+    "SigningPubKey 2 (master seed)" : function () {
+      var seed = Seed.from_json("snoPBrXtMeMyMHUVTgbuqAfg1SUTb");
+      var key = seed.get_key("rHb9CJAWyB4rj91VRWn96DkukG4bwdtyTh");
+      var pub = key.to_hex_pub();
+      buster.assert.equals(pub, "0330E7FC9D56BB25D6893BA3F317AE5BCF33B3291BD63DB32654A313222F7FD020");
+    }
+  }
+});
+
+// vim:sw=2:sts=2:ts=8:et