Async response for built in algo sign/verify

Author: troyfactor4

lib/signed-xml.js

@@ -85,22 +85,24 @@ function RSASHA1() {
   * Sign the given string using the given key
   *
   */
-  this.getSignature = function(signedInfo, signingKey) {
+  this.getSignature = function(signedInfo, signingKey, callback) {
     var signer = crypto.createSign("RSA-SHA1")
     signer.update(signedInfo)
     var res = signer.sign(signingKey, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   /**
   * Verify the given signature of the given string using key
   *
   */
-  this.verifySignature = function(str, key, signatureValue) {
+  this.verifySignature = function(str, key, signatureValue, callback) {
     var verifier = crypto.createVerify("RSA-SHA1")
     verifier.update(str)
     var res = verifier.verify(key, signatureValue, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   this.getAlgorithmName = function() {
@@ -120,22 +122,24 @@ function RSASHA256() {
   * Sign the given string using the given key
   *
   */
-  this.getSignature = function(signedInfo, signingKey) {
+  this.getSignature = function(signedInfo, signingKey, callback) {
     var signer = crypto.createSign("RSA-SHA256")
     signer.update(signedInfo)
     var res = signer.sign(signingKey, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   /**
   * Verify the given signature of the given string using key
   *
   */
-  this.verifySignature = function(str, key, signatureValue) {
+  this.verifySignature = function(str, key, signatureValue, callback) {
     var verifier = crypto.createVerify("RSA-SHA256")
     verifier.update(str)
     var res = verifier.verify(key, signatureValue, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   this.getAlgorithmName = function() {
@@ -154,22 +158,24 @@ function RSASHA512() {
   * Sign the given string using the given key
   *
   */
-  this.getSignature = function(signedInfo, signingKey) {
+  this.getSignature = function(signedInfo, signingKey, callback) {
     var signer = crypto.createSign("RSA-SHA512")
     signer.update(signedInfo)
     var res = signer.sign(signingKey, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   /**
   * Verify the given signature of the given string using key
   *
   */
-  this.verifySignature = function(str, key, signatureValue) {
+  this.verifySignature = function(str, key, signatureValue, callback) {
     var verifier = crypto.createVerify("RSA-SHA512")
     verifier.update(str)
     var res = verifier.verify(key, signatureValue, 'base64')
-    return res
+    if (callback) callback(null, res)
+    else return res
   }
 
   this.getAlgorithmName = function() {