encrypted-message.hpp

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#ifndef NDNPH_PACKET_ENCRYPTED_MESSAGE_HPP
#define NDNPH_PACKET_ENCRYPTED_MESSAGE_HPP
 
#include "../tlv/value.hpp"
 
namespace ndnph {
 
template<uint32_t ivType, size_t ivLen, uint32_t tagType, size_t tagLen, uint32_t epType>
class EncryptedMessage {
public:
  using IvLen = std::integral_constant<size_t, ivLen>;
  using TagLen = std::integral_constant<size_t, tagLen>;
 
  struct InPlace {
    uint8_t* iv = nullptr;
    uint8_t* tag = nullptr;
    uint8_t* ciphertext = nullptr;
  };
 
  static InPlace prependInPlace(Encoder& encoder, size_t ciphertextLen) {
    InPlace result;
    result.ciphertext = encoder.prependRoom(ciphertextLen);
    encoder.prependTypeLength(epType, ciphertextLen);
    if (tagLen > 0) {
      result.tag = encoder.prependRoom(tagLen);
      encoder.prependTypeLength(tagType, tagLen);
    }
    if (ivLen > 0) {
      result.iv = encoder.prependRoom(ivLen);
      encoder.prependTypeLength(ivType, ivLen);
    }
    return result;
  }
 
  void encodeTo(Encoder& encoder) const {
    auto place = prependInPlace(encoder, ciphertext.size());
    if (!encoder) {
      return;
    }
 
    if (ivLen > 0) {
      std::copy(iv.begin(), iv.end(), place.iv);
    }
    if (tagLen > 0) {
      std::copy(tag.begin(), tag.end(), place.tag);
    }
    std::copy(ciphertext.begin(), ciphertext.end(), place.ciphertext);
  }
 
  bool decodeFrom(const Decoder::Tlv& d) {
    switch (d.type) {
      case ivType: {
        if (d.length == ivLen) {
          std::copy_n(d.value, ivLen, iv.begin());
          return true;
        }
        return false;
      }
      case tagType: {
        if (d.length == tagLen) {
          std::copy_n(d.value, tagLen, tag.begin());
          return true;
        }
        return false;
      }
      case epType: {
        ciphertext = tlv::Value(d.value, d.length);
        return true;
      }
    }
    return false;
  }
 
public:
  std::array<uint8_t, ivLen> iv;
  std::array<uint8_t, tagLen> tag;
  tlv::Value ciphertext;
};
 
} // namespace ndnph
 
#endif // NDNPH_PACKET_ENCRYPTED_MESSAGE_HPP