security: rename SignatureSha256 to DigestSha256

Change-Id: Idabb95222d86e2541372593698ed9754156a5df2
diff --git a/src/security/signature-sha256.hpp b/src/security/signature-sha256.hpp
index 28fbc04..e04ba0f 100644
--- a/src/security/signature-sha256.hpp
+++ b/src/security/signature-sha256.hpp
@@ -22,43 +22,9 @@
 #ifndef NDN_SECURITY_SIGNATURE_SHA256_HPP
 #define NDN_SECURITY_SIGNATURE_SHA256_HPP
 
-#include "../data.hpp"
-#include "../encoding/tlv.hpp"
+#include "digest-sha256.hpp"
 
-namespace ndn {
-
-/**
- * Representing of SHA256 signature in a data packet.
- */
-class SignatureSha256 : public Signature
-{
-public:
-  class Error : public Signature::Error
-  {
-  public:
-    explicit
-    Error(const std::string& what)
-      : Signature::Error(what)
-    {
-    }
-  };
-
-  SignatureSha256()
-  {
-    m_info = Block(Tlv::SignatureInfo);
-
-    m_type = Signature::Sha256;
-    m_info.push_back(nonNegativeIntegerBlock(Tlv::SignatureType, Tlv::DigestSha256));
-  }
-
-  SignatureSha256(const Signature& signature)
-    : Signature(signature)
-  {
-    if (getType() != Signature::Sha256)
-      throw Error("Incorrect signature type");
-  }
-};
-
-} // namespace ndn
+///@deprecated
+typedef DigestSha256 SignatureSha256;
 
 #endif //NDN_SECURITY_SIGNATURE_SHA256_HPP