move all models into core

src/Core/Utilities/EncryptedValueAttribute.cs

@@ -0,0 +1,61 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+
+namespace Bit.Core.Utilities
+{
+    /// <summary>
+    /// Validates a string that is in encrypted form: "b64iv=|b64ct="
+    /// </summary>
+    public class EncryptedStringAttribute : ValidationAttribute
+    {
+        public EncryptedStringAttribute()
+            : base("{0} is not a valid encrypted string.")
+        { }
+
+        public override bool IsValid(object value)
+        {
+            if(value == null)
+            {
+                return true;
+            }
+
+            try
+            {
+                var encString = value?.ToString();
+                if(string.IsNullOrWhiteSpace(encString))
+                {
+                    return false;
+                }
+
+                var encStringPieces = encString.Split('|');
+                if(encStringPieces.Length != 2 && encStringPieces.Length != 3)
+                {
+                    return false;
+                }
+
+                var iv = Convert.FromBase64String(encStringPieces[0]);
+                var ct = Convert.FromBase64String(encStringPieces[1]);
+
+                if(iv.Length < 1 || ct.Length < 1)
+                {
+                    return false;
+                }
+
+                if(encStringPieces.Length == 3)
+                {
+                    var mac = Convert.FromBase64String(encStringPieces[2]);
+                    if(mac.Length < 1)
+                    {
+                        return false;
+                    }
+                }
+            }
+            catch
+            {
+                return false;
+            }
+
+            return true;
+        }
+    }
+}