diff --git a/.travis.yml b/.travis.yml
index b3d4c98..656ae12 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,5 @@
 language: node_js
 before_install: npm i -g npm@1.4.28
 node_js:
-  - 0.8
-  - 0.10
\ No newline at end of file
+  - 4
+  - 6
\ No newline at end of file
diff --git a/lib/passport-wsfed-saml2/saml.js b/lib/passport-wsfed-saml2/saml.js
index fd89c74..9c4bb18 100644
--- a/lib/passport-wsfed-saml2/saml.js
+++ b/lib/passport-wsfed-saml2/saml.js
@@ -64,7 +64,7 @@ SAML.prototype.validateSignature = function (xml, options, callback) {
           var base64cer = embeddedSignature[0].firstChild.toString();
           var shasum = crypto.createHash('sha1');
           var der = new Buffer(base64cer, 'base64').toString('binary');
-          shasum.update(der);
+          shasum.update(der, 'latin1');
           self.calculatedThumbprint = shasum.digest('hex');
 
           // using embedded cert, so options.cert is not used anymore
diff --git a/lib/passport-wsfed-saml2/samlp.js b/lib/passport-wsfed-saml2/samlp.js
index 5b90467..0f8c66b 100644
--- a/lib/passport-wsfed-saml2/samlp.js
+++ b/lib/passport-wsfed-saml2/samlp.js
@@ -83,7 +83,7 @@ var removeHeaders = function  (cert) {
 
 var sign = function (content, key, algorithm) {
   var signer = crypto.createSign(algorithm.toUpperCase());
-  signer.update(content);
+  signer.update(content, 'latin1');
   return signer.sign(key, 'base64');
 };