diff --git a/include/ndn-cpp/util/blob.hpp b/include/ndn-cpp/util/blob.hpp
new file mode 100644
index 0000000..af9432d
--- /dev/null
+++ b/include/ndn-cpp/util/blob.hpp
@@ -0,0 +1,112 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/**
+ * Copyright (C) 2013 Regents of the University of California.
+ * @author: Jeff Thompson <jefft0@remap.ucla.edu>
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NDN_BLOB_HPP
+#define	NDN_BLOB_HPP
+
+#include "../common.hpp"
+
+struct ndn_Blob;
+
+namespace ndn {
+
+/**
+ * A Blob holds a pointer to an immutable byte array implemented as const std::vector<uint8_t>.  
+ * This is like a JavaScript string which is a pointer to an immutable string.  
+ * It is OK to pass a pointer to the string because the new owner can't change the bytes
+ * of the string.  However, like a JavaScript string, it is possible to change the pointer, and so this does allow
+ * the copy constructor and assignment to change the pointer.  Also remember that the pointer can be null.
+ * (Note that we could have made Blob derive directly from vector<uint8_t> and then explicitly use
+ * a pointer to it like shared_ptr<Blob>, but this does not enforce immutability because we can't declare
+ * Blob as derived from const vector<uint8_t>.)
+ */
+class Blob : public ptr_lib::shared_ptr<const std::vector<uint8_t> > {
+public:
+  /**
+   * Create a new Blob with a null pointer.
+   */
+  Blob()
+  {  
+  }
+  
+  /**
+   * Create a new Blob with an immutable copy of the given array.
+   * @param value A pointer to the byte array which is copied.
+   * @param valueLength The length of value.
+   */
+  Blob(const uint8_t* value, size_t valueLength)
+  : ptr_lib::shared_ptr<const std::vector<uint8_t> >(new std::vector<uint8_t>(value, value + valueLength))
+  {
+  }
+  
+  /**
+   * Create a new Blob with an immutable copy of the array in the given vector.
+   * If you want to transfer the array without copying, the the vector has to start as a 
+   * ptr_lib::shared_ptr<std::vector<uint8_t> > and you can use the Blob constructor with this type.
+   * @param value A reference to a vector which is copied.
+   */
+  Blob(const std::vector<uint8_t> &value)
+  : ptr_lib::shared_ptr<const std::vector<uint8_t> >(new std::vector<uint8_t>(value))
+  {
+  }
+  
+  /**
+   * Create a new Blob with an immutable copy of the array in the given Blob struct.
+   * @param blobStruct The C ndn_Blob struct to receive the pointer.
+   */
+  Blob(const struct ndn_Blob& blobStruct);
+  
+  /**
+   * Create a new Blob to point to an existing byte array.  IMPORTANT: After calling this constructor,
+   * if you keep a pointer to the array then you must treat the array as immutable and promise not to change it.
+   * @param value A pointer to a vector with the byte array.  This takes another reference and does not copy the bytes.
+   */
+  Blob(const ptr_lib::shared_ptr<std::vector<uint8_t> > &value)
+  : ptr_lib::shared_ptr<const std::vector<uint8_t> >(value)
+  {
+  }
+  Blob(const ptr_lib::shared_ptr<const std::vector<uint8_t> > &value)
+  : ptr_lib::shared_ptr<const std::vector<uint8_t> >(value)
+  {
+  }
+  
+  /**
+   * Return the length of the immutable byte array.
+   */
+  size_t 
+  size() const
+  {
+    if (*this)
+      return (*this)->size();
+    else
+      return 0;
+  }
+
+  /**
+   * Return a const pointer to the first byte of the immutable byte array, or 0 if the pointer is null.
+   */
+  const uint8_t* 
+  buf() const
+  {
+    if (*this)
+      return &(*this)->front();
+    else
+      return 0;
+  }
+  
+  /**
+   * Set the blobStruct to point to this Blob's byte array, without copying any memory.
+   * WARNING: The resulting pointer in blobStruct is invalid after a further use of this object which could reallocate memory.
+   * @param blobStruct The C ndn_Blob struct to receive the pointer.
+   */
+  void 
+  get(struct ndn_Blob& blobStruct) const;
+};
+
+}
+
+#endif
diff --git a/include/ndn-cpp/util/signed-blob.hpp b/include/ndn-cpp/util/signed-blob.hpp
new file mode 100644
index 0000000..7d9c4e1
--- /dev/null
+++ b/include/ndn-cpp/util/signed-blob.hpp
@@ -0,0 +1,121 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+/**
+ * Copyright (C) 2013 Regents of the University of California.
+ * @author: Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ * @author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ * @author: Jeff Thompson <jefft0@remap.ucla.edu>
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NDN_SIGNED_BLOB_HPP
+#define	NDN_SIGNED_BLOB_HPP
+
+#include "blob.hpp"
+
+namespace ndn {
+
+/**
+ * A SignedBlob extends Blob to keep the offsets of a signed portion (e.g., the bytes of Data packet).
+ */
+class SignedBlob : public Blob {
+public:
+  /**
+   * Create a new SignedBlob with a null pointer.
+   */
+  SignedBlob()
+  : signedPortionBeginOffset_(0), signedPortionEndOffset_(0)
+  {  
+  }
+  
+  /**
+   * Create a new SignedBlob with an immutable copy of the given array.
+   * @param value A pointer to the byte array which is copied.
+   * @param valueLength The length of value.
+   * @param signedPortionBeginOffset The offset in the encoding of the beginning of the signed portion.
+   * @param signedPortionEndOffset The offset in the encoding of the end of the signed portion.
+   */
+  SignedBlob
+    (const uint8_t* value, size_t valueLength, size_t signedPortionBeginOffset, size_t signedPortionEndOffset)
+  : Blob(value, valueLength), signedPortionBeginOffset_(signedPortionBeginOffset), signedPortionEndOffset_(signedPortionEndOffset)
+  {
+  }
+  
+  /**
+   * Create a new SignedBlob with an immutable copy of the array in the given vector.
+   * If you want to transfer the array without copying, the the vector has to start as a 
+   * ptr_lib::shared_ptr<std::vector<uint8_t> > and you can use the SignedBlob constructor with this type.
+   * @param value A reference to a vector which is copied.
+   * @param signedPortionBeginOffset The offset in the encoding of the beginning of the signed portion.
+   * @param signedPortionEndOffset The offset in the encoding of the end of the signed portion.
+   */
+  SignedBlob
+    (const std::vector<uint8_t> &value, size_t signedPortionBeginOffset, size_t signedPortionEndOffset)
+  : Blob(value), signedPortionBeginOffset_(signedPortionBeginOffset), signedPortionEndOffset_(signedPortionEndOffset)
+  {
+  }
+  
+  /**
+   * Create a new SignedBlob to point to an existing byte array.  IMPORTANT: After calling this constructor,
+   * if you keep a pointer to the array then you must treat the array as immutable and promise not to change it.
+   * @param value A pointer to a vector with the byte array.  This takes another reference and does not copy the bytes.
+   * @param signedPortionBeginOffset The offset in the array of the beginning of the signed portion.
+   * @param signedPortionEndOffset The offset in the array of the end of the signed portion.
+   */
+  SignedBlob
+    (const ptr_lib::shared_ptr<std::vector<uint8_t> > &value, 
+     size_t signedPortionBeginOffset, size_t signedPortionEndOffset)
+  : Blob(value), signedPortionBeginOffset_(signedPortionBeginOffset), signedPortionEndOffset_(signedPortionEndOffset)
+  {
+  }
+  SignedBlob
+    (const ptr_lib::shared_ptr<const std::vector<uint8_t> > &value, 
+     size_t signedPortionBeginOffset, size_t signedPortionEndOffset)
+  : Blob(value), signedPortionBeginOffset_(signedPortionBeginOffset), signedPortionEndOffset_(signedPortionEndOffset)
+  {
+  }
+    
+  /**
+   * Return the length of the signed portion of the immutable byte array, or 0 of the pointer to the array is null.
+   */
+  size_t 
+  signedSize() const
+  {
+    if (*this)
+      return signedPortionEndOffset_ - signedPortionBeginOffset_;
+    else
+      return 0;
+  }
+
+  /**
+   * Return a const pointer to the first byte of the signed portion of the immutable byte array, or 0 if the 
+   * pointer to the array is null.
+   */
+  const uint8_t*
+  signedBuf() const
+  {
+    if (*this)
+      return &(*this)->front() + signedPortionBeginOffset_;
+    else
+      return 0;
+  }
+
+  /**
+   * Return the offset in the array of the beginning of the signed portion.
+   */  
+  size_t 
+  getSignedPortionBeginOffset() { return signedPortionBeginOffset_; }
+
+  /**
+   * Return the offset in the array of the end of the signed portion.
+   */  
+  size_t 
+  getSignedPortionEndOffset() { return signedPortionEndOffset_; }
+  
+private:
+  size_t signedPortionBeginOffset_;
+  size_t signedPortionEndOffset_;
+};
+
+}
+
+#endif