util: deprecate crypto::computeSha256Digest()

Use Sha256::computeDigest() instead.

Change-Id: I9db5b4839559c9c7930cdc24c78f35ca76b25b52
diff --git a/src/data.cpp b/src/data.cpp
index 8261449..36fdfd4 100644
--- a/src/data.cpp
+++ b/src/data.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2016 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -21,7 +21,7 @@
 
 #include "data.hpp"
 #include "encoding/block-helpers.hpp"
-#include "util/crypto.hpp"
+#include "util/digest.hpp"
 
 namespace ndn {
 
@@ -184,7 +184,7 @@
                                   "(e.g., not signed)"));
     }
     m_fullName = m_name;
-    m_fullName.appendImplicitSha256Digest(crypto::computeSha256Digest(m_wire.wire(), m_wire.size()));
+    m_fullName.appendImplicitSha256Digest(util::Sha256::computeDigest(m_wire.wire(), m_wire.size()));
   }
 
   return m_fullName;
diff --git a/src/interest.cpp b/src/interest.cpp
index 2f54dcb..b35814c 100644
--- a/src/interest.cpp
+++ b/src/interest.cpp
@@ -21,7 +21,6 @@
 
 #include "interest.hpp"
 #include "util/random.hpp"
-#include "util/crypto.hpp"
 #include "data.hpp"
 
 #include <cstring>
diff --git a/src/name-component.cpp b/src/name-component.cpp
index 746f69a..34a3470 100644
--- a/src/name-component.cpp
+++ b/src/name-component.cpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -27,8 +27,8 @@
 
 #include "encoding/block-helpers.hpp"
 #include "encoding/encoding-buffer.hpp"
+#include "util/digest.hpp"
 #include "util/string-helper.hpp"
-#include "util/crypto.hpp"
 
 #include <boost/algorithm/string/trim.hpp>
 
@@ -87,7 +87,6 @@
 {
 }
 
-
 Component
 Component::fromEscapedString(const char* escapedString, size_t beginOffset, size_t endOffset)
 {
@@ -96,7 +95,7 @@
 
   if (trimmedString.compare(0, getSha256DigestUriPrefix().size(),
                             getSha256DigestUriPrefix()) == 0) {
-    if (trimmedString.size() != getSha256DigestUriPrefix().size() + crypto::SHA256_DIGEST_SIZE * 2)
+    if (trimmedString.size() != getSha256DigestUriPrefix().size() + util::Sha256::DIGEST_SIZE * 2)
       BOOST_THROW_EXCEPTION(Error("Cannot convert to ImplicitSha256DigestComponent"
                                   "(expected sha256 in hex encoding)"));
 
@@ -357,15 +356,15 @@
 Component::isImplicitSha256Digest() const
 {
   return (type() == tlv::ImplicitSha256DigestComponent &&
-          value_size() == crypto::SHA256_DIGEST_SIZE);
+          value_size() == util::Sha256::DIGEST_SIZE);
 }
 
 Component
 Component::fromImplicitSha256Digest(const ConstBufferPtr& digest)
 {
-  if (digest->size() != crypto::SHA256_DIGEST_SIZE)
+  if (digest->size() != util::Sha256::DIGEST_SIZE)
     BOOST_THROW_EXCEPTION(Error("Cannot create ImplicitSha256DigestComponent (input digest must be " +
-                                to_string(crypto::SHA256_DIGEST_SIZE) + " octets)"));
+                                to_string(util::Sha256::DIGEST_SIZE) + " octets)"));
 
   return Block(tlv::ImplicitSha256DigestComponent, digest);
 }
@@ -373,9 +372,9 @@
 Component
 Component::fromImplicitSha256Digest(const uint8_t* digest, size_t digestSize)
 {
-  if (digestSize != crypto::SHA256_DIGEST_SIZE)
+  if (digestSize != util::Sha256::DIGEST_SIZE)
     BOOST_THROW_EXCEPTION(Error("Cannot create ImplicitSha256DigestComponent (input digest must be " +
-                                to_string(crypto::SHA256_DIGEST_SIZE) + " octets)"));
+                                to_string(util::Sha256::DIGEST_SIZE) + " octets)"));
 
   return makeBinaryBlock(tlv::ImplicitSha256DigestComponent, digest, digestSize);
 }
diff --git a/src/security/v1/key-chain.cpp b/src/security/v1/key-chain.cpp
index 1916532..9efcb4a 100644
--- a/src/security/v1/key-chain.cpp
+++ b/src/security/v1/key-chain.cpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -24,8 +24,8 @@
 #include "key-chain.hpp"
 #include "../signing-helpers.hpp"
 
-#include "../../util/random.hpp"
 #include "../../util/config-file.hpp"
+#include "../../util/digest.hpp"
 
 #include "sec-public-info-sqlite3.hpp"
 
@@ -755,7 +755,7 @@
                    const Name& keyName, DigestAlgorithm digestAlgorithm) const
 {
   if (keyName == SigningInfo::getDigestSha256Identity())
-    return Block(tlv::SignatureValue, crypto::computeSha256Digest(buf, size));
+    return Block(tlv::SignatureValue, util::Sha256::computeDigest(buf, size));
 
   return m_tpm->signInTpm(buf, size, keyName, digestAlgorithm);
 }
@@ -790,7 +790,7 @@
     .append(sig.getInfo());                                        // signatureInfo
 
   Block sigValue(tlv::SignatureValue,
-                 crypto::computeSha256Digest(signedName.wireEncode().value(),
+                 util::Sha256::computeDigest(signedName.wireEncode().value(),
                                              signedName.wireEncode().value_size()));
 
   sigValue.encode();
diff --git a/src/security/v1/key-chain.hpp b/src/security/v1/key-chain.hpp
index 65821fa..3a84a47 100644
--- a/src/security/v1/key-chain.hpp
+++ b/src/security/v1/key-chain.hpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -32,9 +32,7 @@
 #include "../signature-sha256-with-ecdsa.hpp"
 #include "../digest-sha256.hpp"
 #include "../signing-info.hpp"
-
 #include "../../interest.hpp"
-#include "../../util/crypto.hpp"
 #include "../../util/random.hpp"
 #include <initializer_list>
 
@@ -132,7 +130,7 @@
   /**
    * @brief KeyChain constructor
    *
-   * @sa  http://redmine.named-data.net/issues/2260
+   * @sa  https://redmine.named-data.net/issues/2260
    *
    * @param pibLocator PIB locator
    * @param tpmLocator TPM locator
diff --git a/src/security/v1/public-key.cpp b/src/security/v1/public-key.cpp
index cef7295..7ada249 100644
--- a/src/security/v1/public-key.cpp
+++ b/src/security/v1/public-key.cpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -25,7 +25,7 @@
 #include "public-key.hpp"
 
 #include "../../encoding/oid.hpp"
-#include "../../util/crypto.hpp"
+#include "../../util/digest.hpp"
 #include "cryptopp.hpp"
 
 namespace ndn {
@@ -53,7 +53,7 @@
   if (m_digest.hasWire())
     return m_digest;
   else {
-    m_digest = Block(tlv::KeyDigest, crypto::computeSha256Digest(m_key.buf(), m_key.size()));
+    m_digest = Block(tlv::KeyDigest, util::Sha256::computeDigest(m_key.buf(), m_key.size()));
     m_digest.encode();
     return m_digest;
   }
@@ -119,7 +119,7 @@
 
       m_key.assign(out.begin(), out.end());
     }
-  catch (CryptoPP::BERDecodeErr& err)
+  catch (const CryptoPP::BERDecodeErr& err)
     {
       m_type = KeyType::NONE;
       BOOST_THROW_EXCEPTION(Error("PublicKey decoding error"));
diff --git a/src/security/v2/key-chain.cpp b/src/security/v2/key-chain.cpp
index 45d9277..c6e044c 100644
--- a/src/security/v2/key-chain.cpp
+++ b/src/security/v2/key-chain.cpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -22,6 +22,7 @@
 #include "key-chain.hpp"
 
 #include "../../util/config-file.hpp"
+#include "../../util/digest.hpp"
 #include "../../util/logger.hpp"
 
 #include "../pib/pib-sqlite3.hpp"
@@ -39,7 +40,6 @@
 #include "../transform/private-key.hpp"
 #include "../transform/verifier-filter.hpp"
 #include "../../encoding/buffer-stream.hpp"
-#include "../../util/crypto.hpp"
 
 #include <boost/lexical_cast.hpp>
 
@@ -685,7 +685,7 @@
                const Name& keyName, DigestAlgorithm digestAlgorithm) const
 {
   if (keyName == SigningInfo::getDigestSha256Identity())
-    return Block(tlv::SignatureValue, crypto::computeSha256Digest(buf, size));
+    return Block(tlv::SignatureValue, util::Sha256::computeDigest(buf, size));
 
   return Block(tlv::SignatureValue, m_tpm->sign(buf, size, keyName, digestAlgorithm));
 }
diff --git a/src/security/validator.cpp b/src/security/validator.cpp
index f0f87b7..4862d76 100644
--- a/src/security/validator.cpp
+++ b/src/security/validator.cpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -20,7 +20,7 @@
  */
 
 #include "validator.hpp"
-#include "../util/crypto.hpp"
+#include "../util/digest.hpp"
 #include "../lp/tags.hpp"
 
 #include "v1/cryptopp.hpp"
@@ -234,21 +234,20 @@
 Validator::verifySignature(const uint8_t* buf, const size_t size, const DigestSha256& sig)
 {
   try {
-    ConstBufferPtr buffer = crypto::computeSha256Digest(buf, size);
+    ConstBufferPtr buffer = util::Sha256::computeDigest(buf, size);
     const Block& sigValue = sig.getValue();
 
-    if (buffer != nullptr &&
-        buffer->size() == sigValue.value_size() &&
-        buffer->size() == crypto::SHA256_DIGEST_SIZE) {
+    if (buffer->size() == sigValue.value_size() &&
+        buffer->size() == util::Sha256::DIGEST_SIZE) {
       const uint8_t* p1 = buffer->buf();
       const uint8_t* p2 = sigValue.value();
 
-      return 0 == memcmp(p1, p2, crypto::SHA256_DIGEST_SIZE);
+      return 0 == memcmp(p1, p2, util::Sha256::DIGEST_SIZE);
     }
     else
       return false;
   }
-  catch (const CryptoPP::Exception& e) {
+  catch (const util::Sha256::Error&) {
     return false;
   }
 }
diff --git a/src/util/crypto.cpp b/src/util/crypto.cpp
deleted file mode 100644
index 3083e40..0000000
--- a/src/util/crypto.cpp
+++ /dev/null
@@ -1,47 +0,0 @@
-/* -*- 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.
- */
-
-#include "crypto.hpp"
-#include "../encoding/buffer-stream.hpp"
-#include "../security/transform/buffer-source.hpp"
-#include "../security/transform/digest-filter.hpp"
-#include "../security/transform/stream-sink.hpp"
-
-namespace ndn {
-namespace crypto {
-
-ConstBufferPtr
-computeSha256Digest(const uint8_t* data, size_t dataLength)
-{
-  namespace tr = security::transform;
-  try {
-    OBufferStream os;
-    tr::bufferSource(data, dataLength) >> tr::digestFilter(DigestAlgorithm::SHA256)
-                                       >> tr::streamSink(os);
-    return os.buf();
-  }
-  catch (const tr::Error&) {
-    return nullptr;
-  }
-}
-
-} // namespace crypto
-} // namespace ndn
diff --git a/src/util/crypto.hpp b/src/util/crypto.hpp
index 860b17d..281e2f2 100644
--- a/src/util/crypto.hpp
+++ b/src/util/crypto.hpp
@@ -1,5 +1,5 @@
 /* -*- 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).
@@ -22,14 +22,21 @@
 #ifndef NDN_UTIL_CRYPTO_HPP
 #define NDN_UTIL_CRYPTO_HPP
 
-#include "../common.hpp"
-#include "../encoding/buffer.hpp"
+/**
+ * @file
+ * @deprecated use <ndn-cxx/util/digest.hpp>
+ */
+
+#include "digest.hpp"
 
 namespace ndn {
 namespace crypto {
 
-/// @brief number of octets in a SHA256 digest
-const size_t SHA256_DIGEST_SIZE = 32;
+/**
+ * @brief number of octets in a SHA256 digest
+ * @deprecated use ndn::util::Sha256::DIGEST_SIZE
+ */
+DEPRECATED(const size_t SHA256_DIGEST_SIZE) = util::Sha256::DIGEST_SIZE;
 
 /**
  * @brief Compute the SHA-256 digest of data.
@@ -37,9 +44,15 @@
  * @param data Pointer to the input byte array.
  * @param dataLength The length of data.
  * @return A pointer to a buffer of SHA256_DIGEST_SIZE bytes.
+ *
+ * @deprecated use ndn::util::Sha256::computeDigest()
  */
-ConstBufferPtr
-computeSha256Digest(const uint8_t* data, size_t dataLength);
+DEPRECATED()
+inline ConstBufferPtr
+computeSha256Digest(const uint8_t* data, size_t dataLength)
+{
+  return util::Sha256::computeDigest(data, dataLength);
+}
 
 } // namespace crypto
 } // namespace ndn
diff --git a/src/util/digest.cpp b/src/util/digest.cpp
index 55eb459..8053fdb 100644
--- a/src/util/digest.cpp
+++ b/src/util/digest.cpp
@@ -29,6 +29,8 @@
 namespace ndn {
 namespace util {
 
+const size_t Sha256::DIGEST_SIZE;
+
 Sha256::Sha256()
 {
   reset();
@@ -130,6 +132,14 @@
   return toHex(*buf);
 }
 
+ConstBufferPtr
+Sha256::computeDigest(const uint8_t* buffer, size_t size)
+{
+  Sha256 sha256;
+  sha256.update(buffer, size);
+  return sha256.computeDigest();
+}
+
 std::ostream&
 operator<<(std::ostream& os, Sha256& digest)
 {
diff --git a/src/util/digest.hpp b/src/util/digest.hpp
index 1c3c857..12dbd96 100644
--- a/src/util/digest.hpp
+++ b/src/util/digest.hpp
@@ -22,7 +22,6 @@
 #ifndef NDN_UTIL_DIGEST_HPP
 #define NDN_UTIL_DIGEST_HPP
 
-#include "crypto.hpp"
 #include "../encoding/block.hpp"
 #include "../encoding/buffer-stream.hpp"
 #include "../security/transform/step-source.hpp"
@@ -56,6 +55,11 @@
   };
 
   /**
+   * @brief Length in bytes of a SHA-256 digest.
+   */
+  static const size_t DIGEST_SIZE = 32;
+
+  /**
    * @brief Create an empty SHA-256 digest.
    */
   Sha256();
@@ -156,16 +160,13 @@
   toString();
 
   /**
-   * @brief Compute a one-time SHA-256 digest.
+   * @brief Stateless SHA-256 digest calculation.
    * @param buffer the input buffer
    * @param size the size of the input buffer
    * @return SHA-256 digest of the input buffer
    */
   static ConstBufferPtr
-  computeDigest(const uint8_t* buffer, size_t size)
-  {
-    return crypto::computeSha256Digest(buffer, size);
-  }
+  computeDigest(const uint8_t* buffer, size_t size);
 
 private:
   unique_ptr<security::transform::StepSource> m_input;
diff --git a/src/util/in-memory-storage.cpp b/src/util/in-memory-storage.cpp
index 69f2b5a..bc1beac 100644
--- a/src/util/in-memory-storage.cpp
+++ b/src/util/in-memory-storage.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2013-2016 Regents of the University of California.
+/*
+ * Copyright (c) 2013-2017 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -22,8 +22,6 @@
 #include "in-memory-storage.hpp"
 #include "in-memory-storage-entry.hpp"
 
-#include "crypto.hpp"
-
 #include "../security/signature-sha256-with-rsa.hpp"
 
 namespace ndn {
@@ -423,9 +421,7 @@
 {
   Cache::index<byFullName>::type::iterator it = m_cache.get<byFullName>().end();
 
-  const Data* ptr = NULL;
-
-  return const_iterator(ptr, &m_cache, it);
+  return const_iterator(nullptr, &m_cache, it);
 }
 
 void