diff --git a/lib/verify.js b/lib/verify.js
index b053fd6..3923868 100644
--- a/lib/verify.js
+++ b/lib/verify.js
@@ -73,7 +73,22 @@ module.exports = {
     h1.update(hmac.digest());
     h1 = h1.digest();
     var h2 = crypto.createHmac(hashAlg, secret);
-    h2.update(new Buffer(parsedSignature.params.signature, 'base64'));
+
+    var signatureBase64 = parsedSignature.params.signature;
+    var signatureBuffer;
+    if (Buffer.from && Buffer.from !== Uint8Array.from) {
+      // Node.js 4.5.0 and newer
+      signatureBuffer = Buffer.from(signatureBase64, 'base64');
+    } else {
+      // Node.js <4.5.0 || >=5.0.0 <5.10.0
+      if (typeof signatureBase64 === 'number') {
+        // type-guard against uninitentional uninitialized Buffer allocation
+        throw new Error('Unexpected .signature type: number, string expected');
+      }
+      signatureBuffer = new Buffer(signatureBase64, 'base64');
+    }
+    h2.update(signatureBuffer);
+
     h2 = h2.digest();
 
     /* Node 0.8 returns strings from .digest(). */