diff --git a/src/security/v2/validation-error.hpp b/src/security/v2/validation-error.hpp
new file mode 100644
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--- /dev/null
+++ b/src/security/v2/validation-error.hpp
@@ -0,0 +1,93 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (c) 2013-2017 Regents of the University of California.
+ *
+ * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
+ *
+ * ndn-cxx library is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
+ *
+ * You should have received copies of the GNU General Public License and GNU Lesser
+ * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
+ */
+
+#ifndef NDN_SECURITY_V2_VALIDATION_ERROR_HPP
+#define NDN_SECURITY_V2_VALIDATION_ERROR_HPP
+
+#include "../../common.hpp"
+
+namespace ndn {
+namespace security {
+namespace v2 {
+
+/**
+ * @brief Validation error code and optional detailed error message
+ */
+class ValidationError
+{
+public:
+  /**
+   * @brief Known validation error code
+   * @sa specs/validation-error-code.rst
+   */
+  enum Code : uint32_t {
+    NO_ERROR             = 0,
+    INVALID_SIGNATURE    = 1,
+    NO_SIGNATURE         = 2,
+    CANNOT_RETRIEVE_CERT = 3,
+    EXPIRED_CERT         = 4,
+    LOOP_DETECTED        = 5,
+    MALFORMED_CERT       = 6,
+    EXCEEDED_DEPTH_LIMIT = 7,
+    INVALID_KEY_LOCATOR  = 8,
+    POLICY_ERROR         = 9,
+    IMPLEMENTATION_ERROR = 255,
+    USER_MIN             = 256 // custom error codes should use >=256
+  };
+
+public:
+  /**
+   * @brief Validation error, implicitly convertible from an error code and info
+   */
+  ValidationError(uint32_t code,  const std::string& info = "")
+    : m_code(code)
+    , m_info(info)
+  {
+  }
+
+  uint32_t
+  getCode() const
+  {
+    return m_code;
+  }
+
+  const std::string&
+  getInfo() const
+  {
+    return m_info;
+  }
+
+private:
+  uint32_t m_code;
+  std::string m_info;
+};
+
+std::ostream&
+operator<<(std::ostream& os, ValidationError::Code code);
+
+std::ostream&
+operator<<(std::ostream& os, const ValidationError& error);
+
+} // namespace v2
+} // namespace security
+} // namespace ndn
+
+#endif // NDN_SECURITY_V2_VALIDATION_ERROR_HPP