diff --git a/jsonwebtoken/jsonwebtoken.d.ts b/jsonwebtoken/jsonwebtoken.d.ts
index 16256c24a..4deaf36ce 100644
--- a/jsonwebtoken/jsonwebtoken.d.ts
+++ b/jsonwebtoken/jsonwebtoken.d.ts
@@ -3,9 +3,11 @@
 // Definitions by: Maxime LUCE <https://github.com/SomaticIT>
 // Definitions: https://github.com/borisyankov/DefinitelyTyped
 
+/// <reference path="../node/node.d.ts" /> 
+
 declare module "jsonwebtoken" {
 
-    interface SignOptions {
+    export interface SignOptions {
         /**
          * Signature algorithm. Could be one of these values :
          * - HS256:    HMAC using SHA-256 hash algorithm
@@ -27,40 +29,51 @@ declare module "jsonwebtoken" {
         issuer?: string;
     }
 
-    interface VerifyOptions {
+    export interface VerifyOptions {
         audience?: string;
         issuer?: string;
     }
 
+    export interface VerifyCallbak {
+        (err: Error, decoded: any): void;
+    }
+
     /**
      * Sign the given payload into a JSON Web Token string
-     * @param {string|object|buffer} payload - Payload to sign, could be an literal, buffer or string
-     * @param {string|buffer} secretOrPrivateKey - Either the secret for HMAC algorithms, or the PEM encoded private key for RSA and ECDSA.
-     * @param {SignOptions} options - Options for the signature
-     * @returns The JSON Web Token string
+     * @param {String|Object|Buffer} payload - Payload to sign, could be an literal, buffer or string
+     * @param {String|Buffer} secretOrPrivateKey - Either the secret for HMAC algorithms, or the PEM encoded private key for RSA and ECDSA.
+     * @param {SignOptions} [options] - Options for the signature
+     * @returns {String} The JSON Web Token string
      */
-    function sign(payload: any, secretOrPrivateKey: any, options?: SignOptions): string;
+    export function sign(payload: string, secretOrPrivateKey: string): string;
+    export function sign(payload: string, secretOrPrivateKey: Buffer): string;
+    export function sign(payload: Buffer, secretOrPrivateKey: string): string;
+    export function sign(payload: Buffer, secretOrPrivateKey: Buffer): string;
+    export function sign(payload: Object, secretOrPrivateKey: string): string;
+    export function sign(payload: Object, secretOrPrivateKey: Buffer): string;
+    export function sign(payload: string, secretOrPrivateKey: string, options: SignOptions): string;
+    export function sign(payload: string, secretOrPrivateKey: Buffer, options: SignOptions): string;
+    export function sign(payload: Buffer, secretOrPrivateKey: string, options: SignOptions): string;
+    export function sign(payload: Buffer, secretOrPrivateKey: Buffer, options: SignOptions): string;
+    export function sign(payload: Object, secretOrPrivateKey: string, options: SignOptions): string;
+    export function sign(payload: Object, secretOrPrivateKey: Buffer, options: SignOptions): string;
 
     /**
      * Verify given token using a secret or a public key to get a decoded token
-     * @param {string} token - JWT string to verify
-     * @param {string|buffer} secretOrPublicKey - Either the secret for HMAC algorithms, or the PEM encoded public key for RSA and ECDSA.
+     * @param {String} token - JWT string to verify
+     * @param {String|Buffer} secretOrPublicKey - Either the secret for HMAC algorithms, or the PEM encoded public key for RSA and ECDSA.
+     * @param {VerifyOptions} [options] - Options for the verification
      * @param {Function} callback - Callback to get the decoded token on
      */
-    function verify(token: string, secretOrPublicKey: any, callback: (err: Error, decoded: {}) => void): void;
-    /**
-     * Verify given token using a secret or a public key to get a decoded token
-     * @param {string} token - JWT string to verify
-     * @param {string|buffer} secretOrPublicKey - Either the secret for HMAC algorithms, or the PEM encoded public key for RSA and ECDSA.
-     * @param {VerifyOptions} options - Options for the verification
-     * @param {Function} callback - Callback to get the decoded token on
-     */
-    function verify(token: string, secretOrPublicKey: any, options: VerifyOptions, callback: (err: Error, decoded: {}) => void): void;
+    function verify(token: string, secretOrPublicKey: string, callback: VerifyCallbak): void;
+    function verify(token: string, secretOrPublicKey: Buffer, callback: VerifyCallbak): void;
+    function verify(token: string, secretOrPublicKey: string, options: VerifyOptions, callback: VerifyCallbak): void;
+    function verify(token: string, secretOrPublicKey: Buffer, options: VerifyOptions, callback: VerifyCallbak): void;
 
     /**
      * Returns the decoded payload without verifying if the signature is valid.
-     * @param {string} token - JWT string to decode
-     * @returns The decoded Token
+     * @param {String} token - JWT string to decode
+     * @returns {Object} The decoded Token
      */
-    function decode(token: string): {};
+    function decode(token: string): any;
 }