HMAC algo added

include/jwt/algorithm.hpp

@@ -0,0 +1,233 @@
+#ifndef CPP_JWT_ALGORITHM_HPP
+#define CPP_JWT_ALGORITHM_HPP
+
+#include <cassert>
+#include <system_error>
+
+#include <openssl/bio.h>
+#include <openssl/evp.h>
+#include <openssl/hmac.h>
+#include <openssl/buffer.h>
+
+#include "jwt/string_view.hpp"
+
+namespace jwt {
+
+/// The result type of the signing function
+using sign_result_t = std::pair<std::string, std::error_code>;
+/// The result type of verification function
+using verify_result_t = std::pair<int, std::error_code>;
+/// The function pointer type of the signing function
+using sign_func_t   = sign_result_t (*) (string_view key, string_view data);
+
+namespace algo {
+
+//TODO: All these can be done using code generaion.
+// NO. NEVER. I hate Macros.
+// You can use templates too.
+// No. I would rather prefer explicit.
+// Ok. You win.
+
+/*!
+ */
+struct HS256
+{
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha256();
+  }
+};
+
+/*!
+ */
+struct HS384
+{
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha384();
+  }
+};
+
+/*!
+ */
+struct HS512
+{
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha512();
+  }
+};
+
+/*!
+ */
+struct NONE
+{
+  void operator()() noexcept
+  {
+    return;
+  }
+};
+
+/*!
+ */
+struct RS256
+{
+  static const int type = EVP_PKEY_RSA;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha256();
+  }
+};
+
+/*!
+ */
+struct RS384
+{
+  static const int type = EVP_PKEY_RSA;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha384();
+  }
+};
+
+/*!
+ */
+struct RS512
+{
+  static const int type = EVP_PKEY_RSA;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha512();
+  }
+};
+
+/*!
+ */
+struct ES256
+{
+  static const int type = EVP_PKEY_EC;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha256();
+  }
+};
+
+/*!
+ */
+struct ES384
+{
+  static const int type = EVP_PKEY_EC;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha384();
+  }
+};
+
+/*!
+ */
+struct ES512
+{
+  static const int type = EVP_PKEY_EC;
+
+  const EVP_MD* operator()() noexcept
+  {
+    return EVP_sha512();
+  }
+};
+
+} //END Namespace algo
+
+
+/*!
+ */
+template <typename Hasher>
+struct HMACSign
+{
+  /// The type of Hashing algorithm
+  using hasher_type = Hasher;
+
+  /*!
+   */
+  static sign_result_t sign(string_view key, string_view data)
+  {
+    std::string sign;
+    sign.resize(EVP_MAX_MD_SIZE);
+    std::error_code ec{};
+
+    uint32_t len = 0;
+
+    unsigned char* res = HMAC(Hasher{}(),
+                              key.data(),
+                              key.length(),
+                              reinterpret_cast<const unsigned char*>(data.data()),
+                              data.length(),
+                              reinterpret_cast<unsigned char*>(&sign[0]),
+                              &len);
+
+    if (!res) {
+      //TODO: Set the appropriate error code
+    }
+    sign.resize(len);
+
+    return {std::move(sign), ec};
+  }
+
+  /*!
+   */
+  static verify_result_t 
+  verify(string_view key, string_view head, string_view sign)
+  {
+    int compare_res = 0;
+    std::error_code ec{};
+
+    return {compare_res, ec};
+  }
+
+};
+
+/*!
+ */
+template <>
+struct HMACSign<algo::NONE>
+{
+  using hasher_type = algo::NONE;
+
+  /*!
+   */
+  static sign_result_t sign(string_view key, string_view data)
+  {
+    std::string sign;
+    std::error_code ec{};
+
+    //TODO: Set the appropriate error code for none
+    return {sign, ec};
+  }
+
+  /*!
+   */
+  static verify_result_t
+  verify(string_view key, string_view head, string_view sign)
+  {
+    int compare_res = 0;
+    std::error_code ec{};
+
+    //TODO: Set the appropriate error code for none
+    return {compare_res, ec};
+  }
+
+};
+
+
+/*!
+ */
+
+
+} // END namespace jwt
+
+
+#endif