diff --git a/core/src/main/java/hudson/util/FormFieldValidator.java b/core/src/main/java/hudson/util/FormFieldValidator.java
index 186bcd3a10fa4a1258ecad40037b2569499cbf7a..7d6a37eb0620ac153e2bdc5ed1417f2ea0c439a4 100644
--- a/core/src/main/java/hudson/util/FormFieldValidator.java
+++ b/core/src/main/java/hudson/util/FormFieldValidator.java
@@ -582,6 +582,8 @@ public abstract class FormFieldValidator {
      * Verifies that the 'value' parameter is correct base64 encoded text.
      *
      * @since 1.257
+     * @deprecated as of 1.305
+     *      Use {@link FormValidation#validateBase64(String, boolean, boolean, String)} instead.
      */
     public static class Base64 extends FormFieldValidator {
         private final boolean allowWhitespace;
diff --git a/core/src/main/java/hudson/util/FormValidation.java b/core/src/main/java/hudson/util/FormValidation.java
index cb176973aefb70d32aca11931d11c110e1a97350..96f1f75d7e9f2c6966f9d4f5d414a309087f5785 100644
--- a/core/src/main/java/hudson/util/FormValidation.java
+++ b/core/src/main/java/hudson/util/FormValidation.java
@@ -306,6 +306,35 @@ public abstract class FormValidation extends IOException implements HttpResponse
         }
     }
 
+    /**
+     * Makes sure that the given string is a base64 encoded text.
+     *
+     * @param allowWhitespace
+     *      if you allow whitespace (CR,LF,etc) in base64 encoding
+     * @param allowEmpty
+     *      Is empty string allowed?
+     * @param errorMessage
+     *      Error message.
+     * @since 1.305
+     */
+    public static FormValidation validateBase64(String value, boolean allowWhitespace, boolean allowEmpty, String errorMessage) {
+        try {
+            String v = value;
+            if(!allowWhitespace) {
+                if(v.indexOf(' ')>=0 || v.indexOf('\n')>=0)
+                    return error(errorMessage);
+            }
+            v=v.trim();
+            if(!allowEmpty && v.length()==0)
+                return error(errorMessage);
+
+            com.trilead.ssh2.crypto.Base64.decode(v.toCharArray());
+            return ok();
+        } catch (IOException e) {
+            return error(errorMessage);
+        }
+    }
+
     /**
      * Convenient base class for checking the validity of URLs.
      *