encrypted string length attr

src/Core/Utilities/EncryptedStringLengthAttribute.cs

@@ -0,0 +1,17 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Core.Utilities
+{
+    public class EncryptedStringLengthAttribute : StringLengthAttribute
+    {
+        public EncryptedStringLengthAttribute(int maximumLength)
+            : base(maximumLength)
+        { }
+
+        public override string FormatErrorMessage(string name)
+        {
+            return string.Format("The field {0} exceeds the maximum encrypted value length of {1} characters.",
+                name, MaximumLength);
+        }
+    }
+}